Slides specifically for OCR syallbus during A-Levels, this is for A2 - Unit 4 - Module 2 - 1.2.1 - 1.2.8. I have made these for my students and they have found them very useful.
Includes Summary Questions, Further Application questions and key definitions at the end of the slides
Slides aimed for teachers, but can be used as revision slides for students also.
More than welcome to download, good luck with exams!
The document provides information about the human digestive system and enzymes. It discusses how the digestive system breaks down large food molecules, the sites where digestive enzymes are produced, and the specific enzymes involved in digesting carbohydrates, proteins and lipids. It also addresses how enzymes work using the lock and key model, and factors that affect enzyme activity such as temperature and pH.
This document provides information about enzymes and how they function as biological catalysts in metabolic reactions. It discusses that enzymes are proteins that speed up chemical reactions in cells and do not get used in the reactions. The document describes how enzymes have an active site that binds to substrate molecules in a lock-and-key mechanism. It explains that temperature and pH can affect the shape of the active site and enzyme function, with most enzymes working best around body temperature and pH 7. It proposes a simple experiment using the enzyme amylase to show how reaction time is affected by temperature.
- A balanced diet should include carbohydrates, proteins, lipids, vitamins, minerals, water and fibre. These components have various functions like providing energy, growth and repair.
- The human digestive system includes the mouth, esophagus, stomach, small intestine, large intestine and pancreas. Food moves through the system by peristalsis and is broken down by enzymes.
- Factors like age, activity levels and pregnancy affect energy requirements. Sedentary lifestyles require less energy than active ones. Calorimetry can be used to investigate the energy content of foods.
Edexcel IGCSE - Human Biology - Chapter 14 - Human influences on the environmentChandima Walpita Gamage
This document discusses ecosystems and human influences on the environment. It defines ecosystems and their key components like producers, consumers, and decomposers. It explains photosynthesis and how plants convert glucose for storage, transport, and growth. Food chains and webs show feeding relationships between trophic levels in an ecosystem. Ecological pyramids represent these relationships. The document also covers human waste treatment like sewage systems and pit latrines. It discusses pollution issues like eutrophication from excess nutrients and air pollution from carbon emissions. Reforestation helps address problems caused by deforestation.
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about respiration. For more help with IGCSE Biology please visit mrexham.com
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about classification in the variety of living organisms section. For more help with IGCSE Biology please visit mrexham.com
The document discusses several endocrine glands and hormones, including:
- The thyroid gland, which produces thyroxine to regulate metabolic rate. Thyroxine increases oxygen consumption and protein synthesis.
- The pancreas, which produces insulin and glucagon to regulate blood glucose levels through a negative feedback system. Insulin lowers blood glucose while glucagon raises it.
- The adrenal glands, which produce adrenaline during stressful situations to trigger the fight or flight response through various physiological effects.
This is a PowerPoint presentation for Topic 1 in the Edexcel Biology B A Level course that starts in 2015.
This is a free sample, the full PowerPoint presentation is available to purchase here: https://sellfy.com/MrExham
The document provides information about the human digestive system and enzymes. It discusses how the digestive system breaks down large food molecules, the sites where digestive enzymes are produced, and the specific enzymes involved in digesting carbohydrates, proteins and lipids. It also addresses how enzymes work using the lock and key model, and factors that affect enzyme activity such as temperature and pH.
This document provides information about enzymes and how they function as biological catalysts in metabolic reactions. It discusses that enzymes are proteins that speed up chemical reactions in cells and do not get used in the reactions. The document describes how enzymes have an active site that binds to substrate molecules in a lock-and-key mechanism. It explains that temperature and pH can affect the shape of the active site and enzyme function, with most enzymes working best around body temperature and pH 7. It proposes a simple experiment using the enzyme amylase to show how reaction time is affected by temperature.
- A balanced diet should include carbohydrates, proteins, lipids, vitamins, minerals, water and fibre. These components have various functions like providing energy, growth and repair.
- The human digestive system includes the mouth, esophagus, stomach, small intestine, large intestine and pancreas. Food moves through the system by peristalsis and is broken down by enzymes.
- Factors like age, activity levels and pregnancy affect energy requirements. Sedentary lifestyles require less energy than active ones. Calorimetry can be used to investigate the energy content of foods.
Edexcel IGCSE - Human Biology - Chapter 14 - Human influences on the environmentChandima Walpita Gamage
This document discusses ecosystems and human influences on the environment. It defines ecosystems and their key components like producers, consumers, and decomposers. It explains photosynthesis and how plants convert glucose for storage, transport, and growth. Food chains and webs show feeding relationships between trophic levels in an ecosystem. Ecological pyramids represent these relationships. The document also covers human waste treatment like sewage systems and pit latrines. It discusses pollution issues like eutrophication from excess nutrients and air pollution from carbon emissions. Reforestation helps address problems caused by deforestation.
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about respiration. For more help with IGCSE Biology please visit mrexham.com
This is a presentation designed to help explain the section of the Edexcel IGCSE Biology course about classification in the variety of living organisms section. For more help with IGCSE Biology please visit mrexham.com
The document discusses several endocrine glands and hormones, including:
- The thyroid gland, which produces thyroxine to regulate metabolic rate. Thyroxine increases oxygen consumption and protein synthesis.
- The pancreas, which produces insulin and glucagon to regulate blood glucose levels through a negative feedback system. Insulin lowers blood glucose while glucagon raises it.
- The adrenal glands, which produce adrenaline during stressful situations to trigger the fight or flight response through various physiological effects.
This is a PowerPoint presentation for Topic 1 in the Edexcel Biology B A Level course that starts in 2015.
This is a free sample, the full PowerPoint presentation is available to purchase here: https://sellfy.com/MrExham
Edexcel IGCSE - Human Biology - Chapter 08 - Homeostasis and ExcretionChandima Walpita Gamage
The document summarizes homeostasis and excretion in the human body. It discusses how homeostasis regulates conditions like body temperature, pH, water, salts, glucose, and blood pressure. Disruptions to homeostasis can cause issues like changes in enzyme function, fluid overload, or increased blood pressure. The kidneys and urinary system work to excrete waste and regulate water and salt levels. The nephron is the functional unit of the kidney that filters blood to form urine, reabsorbing useful molecules but removing urea and other wastes. Thermoregulatory mechanisms like sweating and shivering help maintain a stable body temperature.
Mr Exham IGCSE - Movement In And Out Of Cellsmrexham
This document is a PowerPoint presentation on the processes of diffusion, osmosis, and active transport that allow substances to move in and out of cells. It defines each process and explains how surface area, temperature, and concentration gradients affect their rates. It also describes a simple experiment demonstrating diffusion using a semipermeable membrane and solutions with different sugar concentrations.
Cardiac muscle tissue is unique to the heart and has a similar structure to skeletal muscle but works involuntarily like smooth muscle. Hardening of the arteries, called atherosclerosis, is caused by the formation of plaques on artery walls from factors like genetics, age, smoking, diet, and obesity. These plaques can trigger blood clots that block blood flow through arteries.
This document contains review questions about cellular respiration. It asks the student to define terms like aerobic respiration and anaerobic respiration. It also asks the student to label diagrams of aerobic and anaerobic respiration pathways. Finally, it asks the student to compare the key differences between aerobic and anaerobic respiration such as their reactants, products, and location in the cell.
The document provides information about the digestive system. It discusses:
- How the small intestine mixes food with enzymes via muscle contraction and moves it along.
- The pancreas secretes enzymes like amylase, lipase, and an endopeptidase into the small intestine to digest macromolecules.
- Enzymes digest most macromolecules into monomers in the small intestine.
- Villi in the small intestine increase absorption surface area and absorb monomers and nutrients.
- Different membrane transport methods are required to absorb different nutrients like glucose, amino acids, and fatty acids.
The document describes the different levels of organization within organisms, from organelles to cells to tissues to organs to organ systems. It provides examples of structures at each level such as organelles including the nucleus, chloroplasts and mitochondria. Cells include skin cells, muscle cells and neurons. Tissues include muscle, nerves and blood. Organs include the heart, skin and brain. Organ systems include the circulatory, nervous and endocrine systems.
Aerobic respiration is a chemical reaction that takes place in cells to release stored chemical energy. It involves glucose reacting with oxygen to produce carbon dioxide, water, and release energy. Anaerobic respiration occurs when cells do not get enough oxygen, resulting in incomplete breakdown of glucose and lactic acid production, but less energy is released. The rate of aerobic respiration increases with more intense physical activity as cells need more energy, requiring faster breathing and heart rate to supply increased oxygen and glucose.
The document provides information about genetic modification and genetic engineering. It describes the key steps in genetic engineering which include selecting the desired characteristic, using restriction enzymes to cut DNA at specific sites, combining genes using ligase enzymes to create recombinant DNA, and inserting this DNA into an organism using a vector like a plasmid or virus. Vectors are then used to transfer the recombinant DNA into cells where it is replicated to produce the selected characteristic. As an example, the document explains how bacteria can be genetically modified to produce large quantities of human insulin through this process. It also discusses how genetically modified plants can be engineered for improved food production or other traits.
Here are the answers to the questions:
1. In a prokaryotic cell, the genetic material is a single loop of DNA not enclosed in a nucleus.
2. In a eukaryotic cell, the genetic material (DNA) is enclosed within a nucleus.
3. See table below
Prefix Multiple Standard form
centi (cm) 1 cm = 0.01 m x 10-2
milli (mm) 1 mm = 0.001 m x 10-3
micro (μm) 1 μm = 0.000 001 m x 10-6
nano (nm) 1 nm = 0.000 000 001 m x 10-9
4
The circulatory system uses the heart to pump blood throughout the body via blood vessels. The heart has four chambers - two upper atria and two lower ventricles - which work together to circulate blood in two loops. Valves between the chambers prevent backflow of blood. During each heartbeat, the atria contract together then the ventricles contract to pump blood out of the heart.
The document discusses various topics related to human nutrition:
- It describes the essential nutrients that must be consumed as part of our diet, including water, lipids, some amino acids, and vitamins and minerals.
- It then covers digestion, including the roles of the stomach, small intestine, liver, and heart. The stomach aids in protein digestion through gastric juices. The small intestine completes digestion with enzymes from the pancreas and bile from the liver. The liver performs many functions including detoxification and production of proteins and bile. The heart pumps blood throughout the body.
This document defines key terms related to disease transmission and the immune system. It explains that pathogens can transmit diseases through direct or indirect contact. The body has mechanical, chemical, and cellular defenses against pathogens, including white blood cells that distinguish self from non-self and produce antibodies. Vaccination exposes the body to harmless antigens to trigger antibody production and develop immunological memory for long-term protection. Both active and passive immunity are described, with active immunity resulting from infection or vaccination and producing memory cells, while passive immunity involves acquiring antibodies without memory cell development.
Photosynthesis is the process by which plants and other organisms use sunlight, water and carbon dioxide to produce oxygen and energy in the form of glucose. Chlorophyll, located in chloroplasts, absorbs sunlight and uses the energy to convert carbon dioxide and water into oxygen and glucose through a two-step process - the light reactions and Calvin cycle. Plants appear green because chlorophyll, the main photosynthetic pigment, absorbs most wavelengths of visible light except green, which it reflects, giving leaves their green color.
Ventilation refers to the process of moving air in and out of the lungs. Respiration is the cellular process of gas exchange that occurs in the lungs, where oxygen diffuses into the blood and carbon dioxide diffuses out. The ventilation system, which includes the trachea, lungs, bronchi, bronchioles and alveoli, facilitates gas exchange through its features that maximize surface area for diffusion and maintain concentration gradients between the alveoli and blood. The diaphragm, intercostal muscles and abdominal muscles work together to change the volume and pressure of the lungs during breathing to ventilate air in and out.
The document discusses the components of a balanced diet, including carbohydrates, proteins, lipids, vitamins, minerals, water, and dietary fiber. It explains that carbohydrates should make up 45-65% of the diet and are a source of energy. Proteins should make up 10-35% and are needed for growth and cell repair. Lipids provide long-term energy storage and insulation. Vitamins and minerals are micronutrients necessary for proper bodily functions. Energy requirements vary depending on activity levels, age, and pregnancy.
The document summarizes the process of gas exchange in the human respiratory system. It describes the major organs involved, including the lungs, diaphragm, ribs, larynx, trachea, bronchi, bronchioles, and alveoli. It explains how breathing in and out works via the contraction and relaxation of the intercostal muscles and diaphragm. The roles of ciliated cells and mucus in protecting the lungs are also outlined. Finally, it provides details on the composition differences between inspired and expired air.
The document provides information on food, diet, and nutrition. It discusses the main nutrients found in food - carbohydrates, fats, proteins, vitamins, minerals, fiber and water. It explains their sources, functions, and deficiency symptoms. It also covers topics like balanced diet, energy needs, food additives, causes of food shortage and solutions.
1.2.3 - OCR - A2 - Module 2 - Function of the Liver by Piril ErelPırıl Erel
The liver has many important functions including controlling blood glucose and lipid levels, synthesizing proteins and bile, storing vitamins and iron, and detoxifying alcohol and drugs. The liver breaks down excess amino acids through a two-step process of deamination and the ornithine cycle to form urea, which is less toxic than ammonia and is excreted in urine. Chronic alcohol consumption can lead the liver to store fatty acids instead of breaking them down, resulting in fatty liver disease. Genetic variations in cytochrome P450 enzymes mean some people more effectively break down toxic molecules like drugs.
The document discusses agro-ecological solutions and integrated soil fertility management. It summarizes the views of an UN expert who argues that ecological farming practices can boost food production. It also discusses myths and realities around fertilizer use, integrated soil fertility management, and the potential of ISFM combined with other practices like agroforestry.
Edexcel IGCSE - Human Biology - Chapter 08 - Homeostasis and ExcretionChandima Walpita Gamage
The document summarizes homeostasis and excretion in the human body. It discusses how homeostasis regulates conditions like body temperature, pH, water, salts, glucose, and blood pressure. Disruptions to homeostasis can cause issues like changes in enzyme function, fluid overload, or increased blood pressure. The kidneys and urinary system work to excrete waste and regulate water and salt levels. The nephron is the functional unit of the kidney that filters blood to form urine, reabsorbing useful molecules but removing urea and other wastes. Thermoregulatory mechanisms like sweating and shivering help maintain a stable body temperature.
Mr Exham IGCSE - Movement In And Out Of Cellsmrexham
This document is a PowerPoint presentation on the processes of diffusion, osmosis, and active transport that allow substances to move in and out of cells. It defines each process and explains how surface area, temperature, and concentration gradients affect their rates. It also describes a simple experiment demonstrating diffusion using a semipermeable membrane and solutions with different sugar concentrations.
Cardiac muscle tissue is unique to the heart and has a similar structure to skeletal muscle but works involuntarily like smooth muscle. Hardening of the arteries, called atherosclerosis, is caused by the formation of plaques on artery walls from factors like genetics, age, smoking, diet, and obesity. These plaques can trigger blood clots that block blood flow through arteries.
This document contains review questions about cellular respiration. It asks the student to define terms like aerobic respiration and anaerobic respiration. It also asks the student to label diagrams of aerobic and anaerobic respiration pathways. Finally, it asks the student to compare the key differences between aerobic and anaerobic respiration such as their reactants, products, and location in the cell.
The document provides information about the digestive system. It discusses:
- How the small intestine mixes food with enzymes via muscle contraction and moves it along.
- The pancreas secretes enzymes like amylase, lipase, and an endopeptidase into the small intestine to digest macromolecules.
- Enzymes digest most macromolecules into monomers in the small intestine.
- Villi in the small intestine increase absorption surface area and absorb monomers and nutrients.
- Different membrane transport methods are required to absorb different nutrients like glucose, amino acids, and fatty acids.
The document describes the different levels of organization within organisms, from organelles to cells to tissues to organs to organ systems. It provides examples of structures at each level such as organelles including the nucleus, chloroplasts and mitochondria. Cells include skin cells, muscle cells and neurons. Tissues include muscle, nerves and blood. Organs include the heart, skin and brain. Organ systems include the circulatory, nervous and endocrine systems.
Aerobic respiration is a chemical reaction that takes place in cells to release stored chemical energy. It involves glucose reacting with oxygen to produce carbon dioxide, water, and release energy. Anaerobic respiration occurs when cells do not get enough oxygen, resulting in incomplete breakdown of glucose and lactic acid production, but less energy is released. The rate of aerobic respiration increases with more intense physical activity as cells need more energy, requiring faster breathing and heart rate to supply increased oxygen and glucose.
The document provides information about genetic modification and genetic engineering. It describes the key steps in genetic engineering which include selecting the desired characteristic, using restriction enzymes to cut DNA at specific sites, combining genes using ligase enzymes to create recombinant DNA, and inserting this DNA into an organism using a vector like a plasmid or virus. Vectors are then used to transfer the recombinant DNA into cells where it is replicated to produce the selected characteristic. As an example, the document explains how bacteria can be genetically modified to produce large quantities of human insulin through this process. It also discusses how genetically modified plants can be engineered for improved food production or other traits.
Here are the answers to the questions:
1. In a prokaryotic cell, the genetic material is a single loop of DNA not enclosed in a nucleus.
2. In a eukaryotic cell, the genetic material (DNA) is enclosed within a nucleus.
3. See table below
Prefix Multiple Standard form
centi (cm) 1 cm = 0.01 m x 10-2
milli (mm) 1 mm = 0.001 m x 10-3
micro (μm) 1 μm = 0.000 001 m x 10-6
nano (nm) 1 nm = 0.000 000 001 m x 10-9
4
The circulatory system uses the heart to pump blood throughout the body via blood vessels. The heart has four chambers - two upper atria and two lower ventricles - which work together to circulate blood in two loops. Valves between the chambers prevent backflow of blood. During each heartbeat, the atria contract together then the ventricles contract to pump blood out of the heart.
The document discusses various topics related to human nutrition:
- It describes the essential nutrients that must be consumed as part of our diet, including water, lipids, some amino acids, and vitamins and minerals.
- It then covers digestion, including the roles of the stomach, small intestine, liver, and heart. The stomach aids in protein digestion through gastric juices. The small intestine completes digestion with enzymes from the pancreas and bile from the liver. The liver performs many functions including detoxification and production of proteins and bile. The heart pumps blood throughout the body.
This document defines key terms related to disease transmission and the immune system. It explains that pathogens can transmit diseases through direct or indirect contact. The body has mechanical, chemical, and cellular defenses against pathogens, including white blood cells that distinguish self from non-self and produce antibodies. Vaccination exposes the body to harmless antigens to trigger antibody production and develop immunological memory for long-term protection. Both active and passive immunity are described, with active immunity resulting from infection or vaccination and producing memory cells, while passive immunity involves acquiring antibodies without memory cell development.
Photosynthesis is the process by which plants and other organisms use sunlight, water and carbon dioxide to produce oxygen and energy in the form of glucose. Chlorophyll, located in chloroplasts, absorbs sunlight and uses the energy to convert carbon dioxide and water into oxygen and glucose through a two-step process - the light reactions and Calvin cycle. Plants appear green because chlorophyll, the main photosynthetic pigment, absorbs most wavelengths of visible light except green, which it reflects, giving leaves their green color.
Ventilation refers to the process of moving air in and out of the lungs. Respiration is the cellular process of gas exchange that occurs in the lungs, where oxygen diffuses into the blood and carbon dioxide diffuses out. The ventilation system, which includes the trachea, lungs, bronchi, bronchioles and alveoli, facilitates gas exchange through its features that maximize surface area for diffusion and maintain concentration gradients between the alveoli and blood. The diaphragm, intercostal muscles and abdominal muscles work together to change the volume and pressure of the lungs during breathing to ventilate air in and out.
The document discusses the components of a balanced diet, including carbohydrates, proteins, lipids, vitamins, minerals, water, and dietary fiber. It explains that carbohydrates should make up 45-65% of the diet and are a source of energy. Proteins should make up 10-35% and are needed for growth and cell repair. Lipids provide long-term energy storage and insulation. Vitamins and minerals are micronutrients necessary for proper bodily functions. Energy requirements vary depending on activity levels, age, and pregnancy.
The document summarizes the process of gas exchange in the human respiratory system. It describes the major organs involved, including the lungs, diaphragm, ribs, larynx, trachea, bronchi, bronchioles, and alveoli. It explains how breathing in and out works via the contraction and relaxation of the intercostal muscles and diaphragm. The roles of ciliated cells and mucus in protecting the lungs are also outlined. Finally, it provides details on the composition differences between inspired and expired air.
The document provides information on food, diet, and nutrition. It discusses the main nutrients found in food - carbohydrates, fats, proteins, vitamins, minerals, fiber and water. It explains their sources, functions, and deficiency symptoms. It also covers topics like balanced diet, energy needs, food additives, causes of food shortage and solutions.
1.2.3 - OCR - A2 - Module 2 - Function of the Liver by Piril ErelPırıl Erel
The liver has many important functions including controlling blood glucose and lipid levels, synthesizing proteins and bile, storing vitamins and iron, and detoxifying alcohol and drugs. The liver breaks down excess amino acids through a two-step process of deamination and the ornithine cycle to form urea, which is less toxic than ammonia and is excreted in urine. Chronic alcohol consumption can lead the liver to store fatty acids instead of breaking them down, resulting in fatty liver disease. Genetic variations in cytochrome P450 enzymes mean some people more effectively break down toxic molecules like drugs.
The document discusses agro-ecological solutions and integrated soil fertility management. It summarizes the views of an UN expert who argues that ecological farming practices can boost food production. It also discusses myths and realities around fertilizer use, integrated soil fertility management, and the potential of ISFM combined with other practices like agroforestry.
AQA AS Biology - Unit 1 - Biology and Disease - Chapter 2 (2.1 and 2.4) - Dig...Pırıl Erel
Slides specifically for AQA syallbus during A-Levels, this is for unit 1 - biology of disease - chapter 2 (specifically 2.1 and 2.4) I believe these chapters go hand in hand, I have made these for my students and they have found them very useful.
Slides aimed for teachers, but can be used as revision slides for students also.
More than welcome to download, good luck with exams!
The document discusses homeostasis and control systems in the human body. It explains that various internal variables like blood sugar, body temperature, and pH levels must stay within certain ranges to maintain homeostasis. When changes occur internally or externally, feedback systems work to regulate monitors, coordinating centers, and regulators to return levels to the normal range. Negative feedback is the most common type of response that works to reverse changes, while positive feedback reinforces changes. Multiple organ systems interact together to continuously monitor and adjust conditions to uphold homeostasis.
U6 L1 Theory of Evolution by Natural SelectionLori Stroud
This document outlines Charles Darwin's theory of evolution by natural selection. It discusses how Darwin was influenced by his observations on a voyage, including different finch species on the Galapagos Islands. Darwin proposed that organisms vary in traits, some traits help organisms survive and reproduce more successfully, and these traits become more common over generations through natural selection, resulting in evolution of species over time as they adapt to their environments.
Síndrome de down ou trissomia do cromossoma 21Bárbara PJ
A síndrome de Down é causada por uma trissomia no cromossomo 21 e causa dificuldades no desenvolvimento físico e cognitivo, variando de retardo mental leve a moderado. Ela pode ser do tipo trissomia simples, translocação ou mosaico e afeta a aparência facial, habilidades cognitivas, tonia muscular e tendência ao ganho de peso.
The document discusses the role of digestive enzymes in breaking down food molecules in the digestive system. Starch is broken down by amylase into maltose and then further by maltase into glucose. Proteins are broken down by trypsin into peptides and then by peptidases into amino acids. Lipase breaks down fats into fatty acids and glycerol. The structure and specificity of enzymes is also described.
The liver plays a key role in metabolism and homeostasis. It receives a dual blood supply and filters waste from the blood to produce urea, which is excreted. Excess alcohol is broken down but can overload the liver, causing fatty deposits. The kidneys filter blood to produce urine via nephrons and selective reabsorption maintains electrolyte balance. Kidney failure requires dialysis or transplant. Pregnancy and drug tests analyze samples for target hormones or compounds.
hi guys!
This is my latest slide on Excretory system, based on Cambridge GCE 'O' level syllabus.
These slides cover much on the essential points and might not be really comprehensive.
These slides are constructed to be interactive to further boost your understanding by eliminating superfluous words and adding more animations.
Thus, I RECOMMEND you to download the slides to access the many animations to interact with your mind.
Follow my slideshare profile to receive updates on new slides!!
or contact me:
Email: fazzydoo@gmail.com
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if you have questions or would like to address mistakes on my slides or simply just to request me to personally make your slides.
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Ch. 6.2 Theory of Evolution & Natural Selectionsekuhar
Charles Darwin was an English naturalist who developed the theory of evolution in the mid-1800s by observing organisms in their natural environments. He concluded that different tortoises on the Galapagos Islands came from a common ancestor but developed variations due to natural selection. Natural selection occurs when organisms with beneficial variations, like longer necks, live longer, compete better for resources, and reproduce more, passing the variation on to offspring over generations. Through this process, helpful variations can become adaptations that increase an organism's chance of survival.
This document discusses acid-base balance and disorders. It covers 3 key mechanisms to maintain blood pH: 1) blood buffers, 2) respiratory regulation, and 3) renal regulation. The blood's bicarbonate buffer system uses carbonic acid, while tissues also use phosphate and protein buffers. Respiration controls pH by regulating CO2 exhalation. The kidneys compensate for acid-base imbalances over hours by regulating bicarbonate reabsorption and acid excretion. Acid-base disorders include respiratory and metabolic acidosis and alkalosis.
Edexcel a2 unit 4a - Making business decisionsRawVix
The document provides an overview and outline of Unit 4a of the Edexcel GCE08 Business Studies specification, focusing on corporate objectives and strategy. It discusses the development of corporate objectives from mission statements and aims, stakeholder influence on objectives and potential conflicts between stakeholders. It also covers corporate culture, classification of cultures, and difficulties changing culture. Finally, it examines the development of corporate strategy, competitive advantage, strategic matrix, and competition vs cooperation.
Impacts of agriculture, aquaculture on environmentSaad Sair
This document discusses the environmental impacts of agriculture and aquaculture. It notes that while farming can help environments when sustainably practiced, unsustainable practices pose major threats. Key impacts include habitat loss from land conversion, wasteful water consumption, soil erosion, various forms of pollution, contributions to climate change, and loss of genetic diversity. For aquaculture, the document outlines impacts such as destruction of habitats, overexploitation of wild juveniles, water depletion and salinization, disease issues, waste impacts on water quality, and effects of escaped farmed fish.
Theory Of Evolution of Natural Selection by DARWINVipul Sachan
Charles Darwin developed the theory of evolution by natural selection. As a naturalist aboard the HMS Beagle, Darwin made observations and collected evidence that led him to propose that life evolves over generations through a process of natural selection, where organisms better adapted to their environment tend to survive and pass on their traits. Darwin believed that all species on Earth descended with modification from common ancestors over long periods of time. His theory challenged religious orthodoxy and provided a naturalistic explanation for the diversity and complexity of life.
Ecological succession describes the process by which the species in an ecosystem change over time following a disturbance. It can be primary succession, which occurs on new surfaces like lava flows with no previous life, or secondary succession, which follows a disruption but not destruction of an existing community like after a forest fire. Succession proceeds as pioneering species like grasses establish and modify the environment, making it possible for other plants like shrubs and trees to grow and eventually form a stable community. Examples of succession include forests reestablishing on the island of Krakatoa after its 1883 eruption destroyed all life and sand dunes transforming into forests over time along shorelines.
Measure 100 mL of water using a graduated cylinder and pour it
into a 500-mL beaker or tin can.
2.
You: Use a pipette or syringe to carefully add 20 mL of cooking oil on top of
the water in the beaker/tin can. Observe what happens.
All rights reserved. No part of this material may be reproduced or transmitted in any form or by any means -
electronic or mechanical including photocopying – without written permission from the DepEd Central Office. First Edition, 2015.
D
EPED
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357
3.
The document summarizes the digestion and absorption of proteins in the human body. Dietary and endogenous proteins are broken down through digestion by enzymes in the stomach, pancreas, and intestines. In the stomach, pepsin digests proteins into proteoses and peptones. The pancreas secretes trypsin, chymotrypsin, and other enzymes as zymogens which are activated and further break down proteins. In the intestines, aminopeptidases and dipeptidases break down peptides into amino acids, which are then absorbed into the bloodstream through active transport mechanisms.
Ecological succession is the process of change in species composition of an ecological community over time. There are two main types: primary succession, which occurs in areas without previous life, and secondary succession, which occurs after a disturbance in an existing ecosystem. Succession will continue through different stages as species colonize an area and change the environment, eventually reaching a climax community that is stable and able to reproduce itself until the next disturbance. Humans can impact ecological succession through activities like agriculture that clear land and disrupt existing ecosystems.
The document discusses the kidneys and their functions, as well as common kidney diseases and treatments for kidney failure. The kidneys filter waste from the blood and produce hormones. When the kidneys fail, waste builds up and dialysis or transplantation is needed. Common causes of kidney failure include diabetes, high blood pressure, glomerulonephritis, polycystic kidney disease and long term painkiller use. Dialysis options include hemodialysis and peritoneal dialysis, while transplantation provides the best outcomes.
Here are the steps to complete Activity 2:
1. Lay out the 3 figures side by side on a table or the floor.
2. Observe the distribution of earthquake epicenters, volcanoes, and mountain ranges shown in each figure. Note any patterns.
3. On one plastic sheet, use one color pen to trace the outlines of the earthquake epicenters from Figure 5.
4. On the same plastic sheet, use the other color pen to trace the outlines of the volcanoes from Figure 6.
5. On the second plastic sheet, trace the outlines of the mountain ranges from Figure 7 using one of the color pens.
6. Overlay the two plastic sheets and observe
This document discusses the removal of metabolic waste from the body through excretion. It describes two main substances: carbon dioxide and nitrogen-containing compounds like urea. Carbon dioxide is produced by cells during respiration and is transported to the lungs via the bloodstream to be exhaled. Urea is produced in the liver from excess amino acids and transported to the kidneys to be excreted in urine. The document also provides details on where these wastes are produced and excreted from the body.
The document discusses excretion and homeostasis in the body. It covers the roles of the liver and kidneys in excretion. The liver forms urea from excess amino acids and filters toxins from the bloodstream. The kidneys filter waste from the blood to form urine, selectively reabsorbing nutrients. Hormones regulate water reabsorption to maintain osmotic balance.
INTERGRATED RESPONSE TO A MEAL V. INTESTINAL PHASE (ii)SAMOEINESH
The document summarizes the anatomy and physiology of the liver and biliary system. It describes:
1. The liver's dual secretory and excretory functions, and its location in the abdomen.
2. The hepatic lobes, lobules, hepatocytes, and bile canaliculi that make up the liver's structure.
3. How bile is secreted by hepatocytes and stored/concentrated in the gallbladder before release into the small intestine.
The document provides information about the structure and function of the liver. It aims to teach students about the microscopic structures (histology) of the liver and how they relate to liver functions such as deamination of amino acids and the urea cycle. The liver is made up of lobules containing hepatocytes, sinusoids, and Kupffer cells which carry out functions like metabolizing nutrients, filtering blood, and producing bile.
Protein digestion begins in the stomach where pepsin and hydrochloric acid break proteins into smaller polypeptides. In the small intestine, proteases like trypsin further break polypeptides into amino acids. Amino acids are absorbed into the bloodstream and transported to cells. Excess amino acids or those from protein breakdown are converted into urea to be excreted, using glutamate as an intermediate. Urea is produced through a cyclic urea cycle that involves several steps and uses multiple substrates including ammonia, carbon dioxide, and aspartate. Hemoglobin breakdown produces bile pigments like bilirubin that are conjugated and excreted in bile or form the pigments seen in bruises and stools.
The liver performs many essential functions in the body:
- It processes nutrients from the digestive tract, storing glucose and producing proteins, lipids, and other molecules.
- The liver detoxifies the blood, breaking down toxins like alcohol and drugs before they reach the rest of the body.
- It recycles red blood cells by breaking them down and reusing their iron to produce new red blood cells. The liver also produces bile which helps digest and absorb fats.
Protein digestion begins in the stomach through the action of pepsin and hydrochloric acid, which break proteins into smaller polypeptides. In the small intestine, proteases like trypsin and chymotrypsin further break polypeptides into amino acids. Amino acids are absorbed into the bloodstream and transported to cells. Within cells, amino acids undergo transamination, where their amino groups are transferred to alpha-ketoglutarate to form glutamate, and oxidative deamination, where the amino groups are removed as ammonia by glutamate dehydrogenase. Ammonia is toxic, so the liver converts it into urea through the urea cycle, which is then excreted in urine.
This document provides information on excretion in humans and other organisms. It discusses the key organs and processes involved in excretion in the human body, including the lungs, skin, and kidneys. In the kidneys, glomerular filtration occurs, along with reabsorption of useful substances and production of urine. The liver is described as having many functions including detoxification and producing urea from excess proteins. Excretion in plants, fish, and amoebas is also summarized, noting their various adaptations for osmoregulation.
The document discusses body fluids, electrolytes, and acid-base balance. It defines key terms and outlines the normal ranges of electrolytes. It describes the two major body fluid compartments - intracellular and extracellular fluid - and compares their compositions. Homeostasis aims to regulate the composition and volume of both fluid divisions through fluid, electrolyte, and acid-base balance maintained by various mechanisms, including buffers like the bicarbonate system. Respiratory and renal systems work to compensate for changes in acid-base levels to maintain pH within a narrow range.
Composition of Human Body _ Body Fluids and Electrolytes.pptxBrendaKorir2
The document discusses the composition and regulation of fluids, electrolytes, and acid-base balance in the human body. It covers the following key points:
1) The human body is composed of water, proteins, lipids, carbohydrates, and other materials. Water makes up about 60% of body weight and is distributed between intracellular and extracellular fluid compartments.
2) Major electrolytes like sodium, potassium, calcium, and phosphorus are distributed between intracellular and extracellular fluids and their concentrations are tightly regulated.
3) The body maintains acid-base balance through buffering systems like protein, carbonic acid-bicarbonate, and phosphate buffers that control hydrogen ion concentration in fluids.
4
Accessory Organs of Mammalian Digestive SystemGarry D. Lasaga
The liver and pancreas are accessory digestive glands that secrete substances important for digestion. The liver produces bile which aids in fat digestion. It also filters and metabolizes nutrients, stores vitamins and iron, and produces coagulation factors. The pancreas secretes enzymes like trypsin and lipase, as well as bicarbonate, into the small intestine to help break down proteins, carbohydrates, and fats. The gallbladder stores and concentrates bile produced by the liver and releases it in response to food in the duodenum to aid fat digestion.
The liver is the largest gland in the human body, located in the upper right abdominal cavity beneath the diaphragm. It has four lobes and is made up of lobules that contain hepatocytes arranged in plates with blood sinusoids between them. The liver receives blood from the hepatic portal vein and hepatic artery, and filters toxins and produces bile, which is stored in the gallbladder and released into the small intestine after meals to aid in fat digestion. The liver performs many essential metabolic functions including carbohydrate, protein, and fat metabolism, hormone inactivation, and production of bile and proteins.
CHEMICAL PATHOLOGY OF LIVER DISEASE.pptxJasperOmingo
The document summarizes the microscopic structure and functions of the liver. It discusses that the liver is made up of lobules containing hepatocytes and sinusoids which receive blood. The blood flows through sinusoids and drains into central veins. Bile produced by hepatocytes drains into bile ducts. The liver's blood supply comes from the hepatic artery and portal vein. The liver performs important metabolic functions like carbohydrate, lipid, and protein metabolism. It also breaks down bilirubin from broken down red blood cells and conjugates it for excretion in bile. Bile acids are also conjugated and undergo enterohepatic circulation between the liver and intestines.
This document discusses the physiology of the liver, liver function tests, and pathophysiology of jaundice. It begins by listing the learning objectives which are to understand liver functions, hepatic physiology, bilirubin metabolism, the basis for classifying jaundice, and differences in lab findings for different types of jaundice. It then describes the anatomy and blood supply of the liver, histology of liver lobules, bile secretion, and the many functions of the liver including metabolism, storage, detoxification, and immunity. It also discusses liver function tests and the metabolism of bilirubin before explaining the different types of jaundice and their pathophysiology.
The kidney has four main functions: excretory, homeostatic, endocrine, and metabolic. As part of its excretory function, the kidney removes waste from the bloodstream such as urea, uric acid, and creatinine. Its homeostatic functions include regulating blood volume and pressure, stabilizing ion concentrations and pH levels. The kidney also produces important hormones like erythropoietin and renin. Urine is formed through a process of filtration, reabsorption, and secretion as fluid passes through the nephron. Key components like water and electrolytes are reabsorbed while others like urea and drugs are excreted in the urine.
This is a PowerPoint presentation on a chapter based on CBSE syllabus class 10th chapter no. 6 LIFE PROCESSES. It will help you to complete your homework or project work.
Bile is a fluid produced by the liver that aids in digestion. It contains bile salts that emulsify and solubilize lipids, allowing for absorption. Bile is stored in the gallbladder and released in response to hormones like cholecystokinin during a meal. Disruptions to bile composition can lead to gallstones or malabsorption issues like steatorrhea.
The document summarizes the excretory system and its key organs. The lungs, skin, colon, and kidneys work to remove waste from the body. The lungs exhale carbon dioxide, the skin sweats out water and salts, the colon removes bacteria and waste from digestion, and the kidneys filter waste from the bloodstream and regulate water and salt levels. The liver also plays an important role in breaking down toxins, drugs, and other substances before they are excreted by other organs.
Alcohol is metabolized through three main pathways: 1) cytosolic alcohol dehydrogenase and mitochondrial aldehyde dehydrogenase, 2) microsomal ethanol oxidizing system, and 3) non-enzymatic oxidation. Acetaldehyde produced during metabolism is toxic and can damage liver cells, potentially leading to alcoholic hepatitis or cirrhosis over time with heavy drinking. Genetic differences in alcohol and aldehyde metabolizing enzymes also influence toxicity. Moderate drinking may provide some benefits but heavy drinking overwhelms the liver's ability to metabolize alcohol safely.
Similar to A2 - Unit 4 - Module 2 - OCR - Excretion - All Notes Final (20)
Analysis in to the Epidemiology and Pathophysiology of Respiratory Syncytial ...Pırıl Erel
Respiratory Syncytial Virus (RSV) places the heaviest clinical burden on paediatric wards in the UK and the US. It is in fact, a global issue with 3.4 million hospitalisations and approximately 66,000 deaths worldwide per annum (Bush et al., 2007) (Lambert et al., 2014). RSV is the leading cause, especially during the winter months, of severe respiratory infections in infants resulting in a rise in hospital admissions where 0.5-1% of infected babies die from respiratory failure. It is also a significant respiratory concern in the elderly population. (Agoti et al., 2014)
RSV has shown to have a willful ability to enter the host resulting in illness both by viral mechanisms and proteins encoded by RSV, dysregulating the synthesis of systemic immune response of the host. Alongside the infiltration of RSV, the heath status and genotype of the host will be a key factor in predetermining disease susceptibility and severity.
It is important to understand RSV has been implicated with further acute and chronic illnesses therefore by considering the epidemiology and pathophysiology of RSV treatment may be implicated during early stages which can influence possible outcomes in the future.
Analysis in to the Epidemiology and Pathophysiology of Respiratory Syncytial ...Pırıl Erel
Respiratory Syncytial Virus (RSV) places the heaviest clinical burden on paediatric wards in the UK and the US. It is in fact, a global issue with 3.4 million hospitalisations and approximately 66,000 deaths worldwide per annum (Bush et al., 2007) (Lambert et al., 2014). RSV is the leading cause, especially during the winter months, of severe respiratory infections in infants resulting in a rise in hospital admissions where 0.5-1% of infected babies die from respiratory failure. It is also a significant respiratory concern in the elderly population. (Agoti et al., 2014)
RSV has shown to have a willful ability to enter the host resulting in illness both by viral mechanisms and proteins encoded by RSV, dysregulating the synthesis of systemic immune response of the host. Alongside the infiltration of RSV, the heath status and genotype of the host will be a key factor in predetermining disease susceptibility and severity.
It is important to understand RSV has been implicated with further acute and chronic illnesses therefore by considering the epidemiology and pathophysiology of RSV treatment may be implicated during early stages which can influence possible outcomes in the future.
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Candidate young stellar objects in the S-cluster: Kinematic analysis of a sub...Sérgio Sacani
Context. The observation of several L-band emission sources in the S cluster has led to a rich discussion of their nature. However, a definitive answer to the classification of the dusty objects requires an explanation for the detection of compact Doppler-shifted Brγ emission. The ionized hydrogen in combination with the observation of mid-infrared L-band continuum emission suggests that most of these sources are embedded in a dusty envelope. These embedded sources are part of the S-cluster, and their relationship to the S-stars is still under debate. To date, the question of the origin of these two populations has been vague, although all explanations favor migration processes for the individual cluster members. Aims. This work revisits the S-cluster and its dusty members orbiting the supermassive black hole SgrA* on bound Keplerian orbits from a kinematic perspective. The aim is to explore the Keplerian parameters for patterns that might imply a nonrandom distribution of the sample. Additionally, various analytical aspects are considered to address the nature of the dusty sources. Methods. Based on the photometric analysis, we estimated the individual H−K and K−L colors for the source sample and compared the results to known cluster members. The classification revealed a noticeable contrast between the S-stars and the dusty sources. To fit the flux-density distribution, we utilized the radiative transfer code HYPERION and implemented a young stellar object Class I model. We obtained the position angle from the Keplerian fit results; additionally, we analyzed the distribution of the inclinations and the longitudes of the ascending node. Results. The colors of the dusty sources suggest a stellar nature consistent with the spectral energy distribution in the near and midinfrared domains. Furthermore, the evaporation timescales of dusty and gaseous clumps in the vicinity of SgrA* are much shorter ( 2yr) than the epochs covered by the observations (≈15yr). In addition to the strong evidence for the stellar classification of the D-sources, we also find a clear disk-like pattern following the arrangements of S-stars proposed in the literature. Furthermore, we find a global intrinsic inclination for all dusty sources of 60 ± 20◦, implying a common formation process. Conclusions. The pattern of the dusty sources manifested in the distribution of the position angles, inclinations, and longitudes of the ascending node strongly suggests two different scenarios: the main-sequence stars and the dusty stellar S-cluster sources share a common formation history or migrated with a similar formation channel in the vicinity of SgrA*. Alternatively, the gravitational influence of SgrA* in combination with a massive perturber, such as a putative intermediate mass black hole in the IRS 13 cluster, forces the dusty objects and S-stars to follow a particular orbital arrangement. Key words. stars: black holes– stars: formation– Galaxy: center– galaxies: star formation
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CLASS 12th CHEMISTRY SOLID STATE ppt (Animated)eitps1506
Description:
Dive into the fascinating realm of solid-state physics with our meticulously crafted online PowerPoint presentation. This immersive educational resource offers a comprehensive exploration of the fundamental concepts, theories, and applications within the realm of solid-state physics.
From crystalline structures to semiconductor devices, this presentation delves into the intricate principles governing the behavior of solids, providing clear explanations and illustrative examples to enhance understanding. Whether you're a student delving into the subject for the first time or a seasoned researcher seeking to deepen your knowledge, our presentation offers valuable insights and in-depth analyses to cater to various levels of expertise.
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Crystal Structures: Unravel the mysteries of crystalline arrangements and their significance in determining material properties.
Band Theory: Explore the electronic band structure of solids and understand how it influences their conductive properties.
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Magnetic Properties: Investigate the magnetic behavior of solids, including ferromagnetism, antiferromagnetism, and ferrimagnetism.
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The pathway(s) to seeding the massive black holes (MBHs) that exist at the heart of galaxies in the present and distant Universe remains an unsolved problem. Here we categorise, describe and quantitatively discuss the formation pathways of both light and heavy seeds. We emphasise that the most recent computational models suggest that rather than a bimodal-like mass spectrum between light and heavy seeds with light at one end and heavy at the other that instead a continuum exists. Light seeds being more ubiquitous and the heavier seeds becoming less and less abundant due the rarer environmental conditions required for their formation. We therefore examine the different mechanisms that give rise to different seed mass spectrums. We show how and why the mechanisms that produce the heaviest seeds are also among the rarest events in the Universe and are hence extremely unlikely to be the seeds for the vast majority of the MBH population. We quantify, within the limits of the current large uncertainties in the seeding processes, the expected number densities of the seed mass spectrum. We argue that light seeds must be at least 103 to 105 times more numerous than heavy seeds to explain the MBH population as a whole. Based on our current understanding of the seed population this makes heavy seeds (Mseed > 103 M⊙) a significantly more likely pathway given that heavy seeds have an abundance pattern than is close to and likely in excess of 10−4 compared to light seeds. Finally, we examine the current state-of-the-art in numerical calculations and recent observations and plot a path forward for near-future advances in both domains.
PPT on Direct Seeded Rice presented at the three-day 'Training and Validation Workshop on Modules of Climate Smart Agriculture (CSA) Technologies in South Asia' workshop on April 22, 2024.
SDSS1335+0728: The awakening of a ∼ 106M⊙ black hole⋆Sérgio Sacani
Context. The early-type galaxy SDSS J133519.91+072807.4 (hereafter SDSS1335+0728), which had exhibited no prior optical variations during the preceding two decades, began showing significant nuclear variability in the Zwicky Transient Facility (ZTF) alert stream from December 2019 (as ZTF19acnskyy). This variability behaviour, coupled with the host-galaxy properties, suggests that SDSS1335+0728 hosts a ∼ 106M⊙ black hole (BH) that is currently in the process of ‘turning on’. Aims. We present a multi-wavelength photometric analysis and spectroscopic follow-up performed with the aim of better understanding the origin of the nuclear variations detected in SDSS1335+0728. Methods. We used archival photometry (from WISE, 2MASS, SDSS, GALEX, eROSITA) and spectroscopic data (from SDSS and LAMOST) to study the state of SDSS1335+0728 prior to December 2019, and new observations from Swift, SOAR/Goodman, VLT/X-shooter, and Keck/LRIS taken after its turn-on to characterise its current state. We analysed the variability of SDSS1335+0728 in the X-ray/UV/optical/mid-infrared range, modelled its spectral energy distribution prior to and after December 2019, and studied the evolution of its UV/optical spectra. Results. From our multi-wavelength photometric analysis, we find that: (a) since 2021, the UV flux (from Swift/UVOT observations) is four times brighter than the flux reported by GALEX in 2004; (b) since June 2022, the mid-infrared flux has risen more than two times, and the W1−W2 WISE colour has become redder; and (c) since February 2024, the source has begun showing X-ray emission. From our spectroscopic follow-up, we see that (i) the narrow emission line ratios are now consistent with a more energetic ionising continuum; (ii) broad emission lines are not detected; and (iii) the [OIII] line increased its flux ∼ 3.6 years after the first ZTF alert, which implies a relatively compact narrow-line-emitting region. Conclusions. We conclude that the variations observed in SDSS1335+0728 could be either explained by a ∼ 106M⊙ AGN that is just turning on or by an exotic tidal disruption event (TDE). If the former is true, SDSS1335+0728 is one of the strongest cases of an AGNobserved in the process of activating. If the latter were found to be the case, it would correspond to the longest and faintest TDE ever observed (or another class of still unknown nuclear transient). Future observations of SDSS1335+0728 are crucial to further understand its behaviour. Key words. galaxies: active– accretion, accretion discs– galaxies: individual: SDSS J133519.91+072807.4
3. What is excretion?
Excretion = the removal of metabolic waste from the body
Metabolic waste = consists of waste substances that may be toxic or are
produced in excess by the reactions inside cells.
There are 2 substances that are produced in very large amounts:
Carbon dioxide
Nitrogen containing compounds such as urea
Note: EGESTION is when your body removes undigested food by the process of
defecation. EXCRETION is when your body removes metabolic waste which has
entered your cells.
5/17/2015 3
4. Where are these substances
excreted?
Carbon dioxide is passed from the cells of respiring tissues into the
bloodstream. It is transported in the blood (mostly in the form of
hydrogencarbonate ions) to the lungs. In the lungs the carbon dioxide diffuses
into the alveoli to be excreted as we breathe.
Urea is made from the break down of excess amino acids in the liver. This
process is called deamination. Urea is passed into the bloodstream to be
transported to the kidneys.
it is transported in solution (dissolved in plasma)
In the kidneys, urea is removed from the blood to become a part of urine.
Urine is stored in the bladder before being excreted via the urethra.
5/17/2015 4
5. Why must these substances be remove?
Part I
Carbon dioxide:
Excess carbon dioxide can lead to toxicity via three main effects:
1. Carbon dioxide is transported in the blood as hydrogencarbonate ions. This occurs
inside the red blood cells under the influence of carbonic anhydrase
H2CO3 H+ + HCO3
-
The hydrogen ions combine with haemoglobin. They compete with oxygen for space
on the haemoglobin. If there is too much carbon dioxide in the blood it will reduce
oxygen transport
2. Carbon dioxide when bound to haem forms carbaminohaemoglobin. (Carbon
dioxide has a higher affinity for haem, when the compound is formed
carbaminohaemoglobin will have a lower affinity for oxygen than normal haem)
Therefore it becomes difficult for oxygen to attach onto haem as carbon dioxide
is strongly associated with haem.
5/17/2015 5
6. Why must these substances be removed?
Part II
3. Excess carbon dioxide can cause respiratory acidosis. The carbon dioxide dissolves in
the blood plasma. Once dissolved it can combine with water to produce carbonic acid:
CO2 + H2O H2CO3
The carbonic acid dissociates to release hydrogen ions
H2CO3 H+ + HCO3
-
The hydrogen ions lower the pH acidity within the blood circulation. Proteins in the
blood act as buffers to resist the change in pH.
If the pH change is small the extra H+ ions are detected by the respiratory centre in the
medulla oblongata of the brain resulting in
Increased breathing rate removing excess carbon dioxide
5/17/2015 6
7. Why must these substances be removed?
Part III
If the pH drops below 7.3 it results
in
slowed or difficult breathing, headache,
drowsiness, restlessness, tremor and confusion.
May also be a rapid heart rate and changes in
blood pressure.
THIS IS RESPIRATORY ACIDOSIS (A MEDICAL
EMERGENCY, NEEDS TREATMENT IMMEDIATELY)
Respiratory acidosis can also be caused by
diseases or conditions that affect the lungs
themselves due to blockage of airway
leading to increase in carbon dioxide.
These diseases include; emphysema,
chronic bronchitis, asthma or severe
pneumonia. Conditions such as swelling, a
foreign object or vomit in the airways are
also causative.
5/17/2015 7
8. Why must these substances be removed?
Part IV
Nitrogenous Compounds:
The body cannot store proteins or amino acids(aa). However, aa contain as much
energy as carbohydrates, therefore we do not want to waste this energy source.
AA are transported to the liver and the potentially toxic amino group is removed
(deamination).
Step 1 -The amino group initially forms a very soluble and highly toxic compound =
ammonia
Amino acid + oxygen keto acid + ammonia
Step 2 - Ammonia is converted to a less soluble and less toxic compound = urea
Ammonia + carbon dioxide urea + water
2NH3 + CO2 CO(NH2)2 + H2O
Urea is then transported to the kidneys for excretion. The remaining keto acid can
be used directly in respiration to release its energy or it may be converted to a
carbohydrate or fat for storage.
5/17/2015 8
10. The structure of the liver
The liver cells namely the
hepatocytes carry hundreds of
metabolic processes and has an
important role in homeostasis.
Therefore it is essential for a
continuous supply of blood. The
internal structure of the liver is
arranged to ensure that as much
blood flows past as many liver cells
as possible
5/17/2015 10
11. Blood flow to the liver
TO:
The liver has two blood supplies
Oxygenated blood from the heart. Blood
travels from the aorta via the HEPATIC
ARTERY INTO THE LIVER.
This supplies the oxygen essential for
aerobic respiratory. Hepatocytes are very
active and require energy in the form of
ATP so it is essential there is a good
oxygen supply.
Deoxygenated blood from the digestive
system. This enters the liver via the
HEPATIC PORTAL VEIN. This blood is
rich in the products of digestion. The
concentration of the various compounds
will be uncontrolled and the blood may
contain toxic compounds that have been
absorbed by the intestine.
5/17/2015 11
12. Blood flow from the liver
FROM:
Blood leaves the liver via the
HEPATIC VEIN. This re-joins the vena
cava and the blood returns to normal
circulation
A Fourth vessel connected to the
liver is not a blood vessel. It is the
bile duct. Bile is a secretion from the
liver. It has both a digestive function
and an excretory function. The bile
duct carries bile from the LIVER TO
THE GALLBLADDER where it is stored
until required to aid the digestion of
fats in the small intestine.
5/17/2015 12
13. The arrangement of cells inside the liver
The liver is divided into lobes and further divided into
cylindrical lobules.
As the hepatic artery and hepatic portal vein enter the
liver, they split into smaller and smaller vessels which run
parallel or between the lobules and are known as inter-
lobular vessels.
The blood from two blood vessels are mixed and passed
through a special chamber called sinusoid which
furthermore empty into the intra-lobular vessels a branch of
the hepatic vein.
The branches of the hepatic vein from different lobules join
together to form the hepatic vein draining blood from the
liver.
As blood moves along the sinusoid it is in very close contact
with the liver cells. They are able to remove molecules
from the blood and pass molecules into the blood.
One of the many functions of the liver cells is to
manufacture bile. This is released into the bile canaliculi
(small canals). These join together to form the bile duct,
which transports the bile to the gall bladder.
5/17/2015 13
14. Liver Cells
Hepatocytes are unspecialised simple cuboidal shaped cells which have many
microvilli on their surface
They are however involved in many metabolic functions including;
Protein synthesis
Transformation
Storage of carbohydrates
Synthesis of cholesterol and bile salts
Detoxification and other processes
This means that their cytoplasm must be very dense and is specialised in the
amounts of certain organelles that it contains
5/17/2015 14
15. Kupffer cells
Kupffer cells are specialised macrophages
moving about in the sinusoids involved in the
breakdown and recycling of red blood cells. A
product it produces during breakdown is
bilirubin which is excreted as part of the bile
and in faces. Bilirubin is the brown pigment is
faeces.
Application Scenario:
A common condition in newborns, jaundice
refers to the yellow color of the skin and
whites of the eyes caused by excess bilirubin
in the blood.
It is also seen in adults where an excess
chronic consumption of alcohol can have
damaging effects on your liver meaning that
you are not removing bilirubin from your liver
and bile ducts quickly enough, as it builds up in
the blood it is deposited in the skin… The
resulting is jaundice.
5/17/2015 15
17. Wide Range of functions of the liver
Control of:
Blood glucose levels, amino acid levels, lipid levels
Synthesis of:
RBC in the fetus, bile, plasma proteins, cholesterol
Storage of:
Vitamins A, D and B12 , iron, glycogen
Detoxification of:
Alcohol and drugs
Breakdown of hormones
Destruction of RBCs
5/17/2015 17
18. Formation of Urea
Daily requirement is 40-60g of protein, but daily consumption is far
more greater therefore, breakdown of amino acids are needed as
accumulation leads to toxicity.
Two step process occurs in the liver before the amino acid component
is excreted
DEAMINATION
ORNITHINE CYCLE
5/17/2015 18
19. Formation of Urea
DEAMINATION:
Removal of NH3 group fro the amino acid with oxygen forming a keto acid (-RCOCOOH) and
Ammonia (NH3)
Ammonia is highly toxic and very soluble therefore should not be allowed to accumulate in the
blood circulation.
On removal of NH3 group energy is released.
THE ORNITHINE CYCLE:
Ammonia is converted into a less soluble and less toxic substance when combined with CO2
forming Urea.
Urea is further passed into the blood circulation and into the kidneys where it is filtered out
of the blood circulation and is concentrated in the urine.
5/17/2015 19
20. Detoxification
The liver detoxifies alcohol and drugs. Toxins can also be rendered harmless by oxidation,
reduction, methylation or a combination with another molecule.
Liver cells contain many enzymes that enable rendering of toxic molecules less toxic form.
This includes catalase which converts H2O2 to oxygen and water
DETOXIFICATION OF ALCOHOL:
Alcohol is a CNS depressant; contains a lot of energy that can be used for respiration.
STEP 1: Ethanol Ethanol dehydrogenase Ethanal (occurs in the hepatocytes)
STEP 2: Ethanal Ethanal dehydrogenase Ethanoic acid
STEP 3: Ethanoic acid Ethanoate + CoA Acetyl CoA
The hydrogens release in the steps above are combined with NAD NADH
NAD is required to oxidise and breakdown fatty acids for use in respiration
5/17/2015 20
21. Future Possible Complications
If the liver has to detoxify too
much alcohol it has insufficient
NAD to deal with the fatty acids.
These fatty acids are converted
back to lipids and are stored in the
hepatocytes, causing the liver to
become enlarged
Causes a condition known as fatty
liver alcohol-related hepatitis
or cirrhosis.
5/17/2015 21
22. Stretching Your Knowledge
Scenario:
Liver cells contain a large group of enzymes called the cytochrome P450 enzymes.
These are responsible for the breakdown of some toxic molecules, such as cocaine
and other drugs (recreational and medicinal). The P450s are most concentrated in
the endoplasmic reticulum of liver cells. As a result of variation these enzymes can
be more effective in some people than in others (Caucasian population compared
to Afro-Caribean population)
Many drugs can be more effective in some people than in others and may also
cause variable side effects
Task:
1. Suggest why the P450s are most concentrated in the endoplasmic reticulum?
2. Suggest why many medicinal drugs have different side effects in different people
3. Explain why the P450s are not identical in every person.
5/17/2015 22
The P450s are proteins; these are manufactured by the ribosomes that are attached to the
endoplasmic reticulum – they can be packaged in vesicles and transported to where they are
needed
Each person may have slightly different enzymes (evolution). These may break the drugs down in a
slightly different way producing different by-products (SEs)
Genetic variation means that different people will have different alleles – these will produce
slightly different enzymes.
23. Questions:
1. Why must ammonia be converted to urea?
2. Explain why excess amino acids and alcohol should not be excreted?
3. Suggest why the liver cells have large number of mitochondria and ribosomes
5/17/2015 23
Ammonia is highly soluble and very toxic; urea is less soluble and less toxic
They contain valuable energy that can be converted to useable forms. Some
amino acids can be converted into other amino acids
The mitochondria provide ATP (metabolic energy) for the active or energy-
requiring processes, e.g. protein synthesis, mitosis, active transport, endo
and exocytosis. The ribosomes manufacture the many enzymes that are
needed in liver cells.
25. The structure of the kidney
Positioned at each side of the spine
just below the lowest rib
Supplied with blood from a renal
artery and is drained by a renal
vein
JOB: - remove waste products from
the blood and to produce urine.
Urine passes out of the kidney
down the ureter to the bladder
where it can be stored before
release
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26. The Nephron
- Part I
The bulk of each kidney consists of
tiny tubules called nephrons.
They are closely associated with
tiny blood capillaries
Each nephron starts in the cortex
In the cortex the capillaries form a
knot called the glomerulus
This is surrounded by a cup-shaped
structure called the Bowman’s
Capsule
Fluid from the blood is pushed into
the Bowman’s capsule by the
process of ultrafiltration
5/17/2015 26
27. The Nephron
- Part II
The capsule leads into the nephron which
is divided into 4 parts:
The proximal convoluted tubule
Loop of Henle (Descending and
Ascending Limb)
Distal convoluted tubule
Collecting duct
As fluid moves along the nephron its
composition is altered. This is achieved
by selective reabsorption. Substances are
reabsorbed back into the tissue fluid and
blood capillaries surrounding the nephron
tubule.
The final product in the collecting duct is
urine, passed into the pelvis ureter
bladder.
5/17/2015 27
28. How does the composition of the fluid
change?
In the PCT the fluid is altered by the reabsorption of all the sugars, most salts
and some water
In total about 85% of the fluid is reabsorbed here
In the DL of the Loop of Henle, the water potential of the fluid is decreased
by the addition of salts and removal of water
In the AL of the Loop of Henle, the water potential of the fluid is increased as
salts are removed by active transport
In the collecting duct the water potential is decreased again by the removal
of water.
This ensures that the final product (urine) has a low water potential.
Urine has a higher concentration of solutes than is found in the blood and tissue
fluid.
5/17/2015 28
29. Questions:
1. Suggest why the nephrons are convoluted
2. Why are there many capillaries around each nephron?
3. Explain why reabsorption from the nephron must be selective
5/17/2015 29
The fact that the nephrons are convoluted allows there to be an increase the
length for greater surface area for absorption or filtration. This ensures
accuracy and minimizes loss in terms of absorption of useful molecules
required for the body.
Materials reabsorbed from the fluid in the tubule can re-enter the blood
circulation
Some of the molecules in the nephron are waste and must be left in the fluid
to be excreted. Other molecules are useful to the body and must be
reabsorbed.
30. Practice Exam Questions:
1. What is meant by the term excretion? [2 marks]
2. Name the two excretory products produced in mammals [2 marks]
3. Name the two organs that remove these products from the body [2 marks]
4. Name the blood vessels that carry blood to the liver [2 marks]
5. What is a sinusoid and where is it found? [2 marks]
6. What is a hepatocyte? [1 marks]
7. What is meant by the term deamination? [2 marks]
8. What occurs during the ornithine cycle? [2 marks]
9. Name the three sections of the kidney as seen in longitudinal section [3 marks]
10. Name the tubules found in the kidney [2 marks]
5/17/2015 30
31. Practice Exam Question:
ANSWERS
1. The removal of waste products from cell metabolism
2. Carbon dioxide and urea
3. The lungs and the kidneys
4. The hepatic artery( oxygenated blood) and hepatic portal vein (deoxygenated
blood)
5. A sinusoid is a channel between the liver cells; they are found in the liver lobules
6. A liver cell
7. The removal of the amino group from an amino acid forming ammonia and leaving
a ketose residue
8. The conversion of ammonia to urea by the addition of carbon dioxide
9. Cortex, medulla and pelvis
10. Nephrons
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34. Ultrafiltration
- PART I
Blood flows through the afferent
arteriole into the glomerulus and blood
leaves through the efferent arteriole
Afferent arteriole is wider in diameter
than the efferent arteriole
Efferent arteriole is an arteriole – which
is muscular and can constrict to raise the
blood pressure in the glomerulus. In most
organs a venule carries away blood away
This difference ensures the glomerulus
is higher in pressure in comparison to
the pressure in the Bowman’s capsule
This pressure differences pushes the
fluid from the blood into the Bowman’s
capsule
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35. Ultrafiltration
- PART II
The barrier between the blood in
the capillary and the lumen of the
Bowman’s capsule consists of three
layers:
Endothelium of the capillary
A basement membrane
The epithelial cells of the
Bowman’s capsule (podocytes)
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36. Ultrafiltration
- PART III
Each structure is adapted to allow ultrafiltration:
Fenestrated Endothelium – narrow gaps between each endothelium cells – blood
plasma and substances dissolved in blood plasma can pass through these narrow
gaps
Basement membrane – fine mesh of collagen fibres and glycoprotein
This filter prevent the passage of molecules with a relatively high molecular mass. All
proteins (and all blood cells) are held in the capillaries of the glomerulus
Epithelial cells of the Bowman’s capsule are called PODOCYTES which have a
specialized shape.
Podocytes have finger-like projections called major processes. Ensuring that gaps are
present in between cells.
The fluid from the blood in the glomerulus can pass between these cells into the lumen of
the Bowman’s capsule
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37. What is filtered out of the blood?
Blood plasma containing dissolved substances is pushed under pressure from
the capillary into the lumen of the Bowmans capsule. This includes the
following substances:
Water
Amino acids
Glucose
Urea
Inorganic ions (Na+, Cl-, K+)
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38. What is left in the capillary?
The blood cells and proteins are left in the capillary
Presence of the proteins means that the blood has a very low (very negative)
water potential
Due to this low water potential it ensures that some of the fluid is retained in the
blood, and this contains some of the water and dissolved substances listed above
The very low water potential of the blood in the capillaries is important to help
reabsorb water at a later stage.
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39. Stretching Your Knowledge
Scenario:
High Blood pressure can damage the capillaries of the glomerulus and the
epithelium of Bowman’s capsule.
Task:
Explain why the presence of protein in urine can be a sign of hypertension?
5/17/2015 39
Proteins are normally filtered by the basement membrane. If this has been damaged by high
blood pressure then proteins can enter bowmans capsule from the blood and pass into the urine
presenting as proteinuria
40. Selective Reabsorption
- PART I
Reabsorption is achieved by a combination of processes described below. The cells
lining the proximal convoluted tubule are specialized to achieve this reabsorption:
PCT cells are highly folded forming microvilli for increase surface area for reabsorption
PCT cells also have special co-transporter proteins transporting glucose or amino acids,
in association with sodium ions from the tubule into the cell facilitated diffusion
Molecules are moving from a high water potential to a low water potential (no ATP is required)
PCT cells lined towards the capillaries are also highly folded forming microvilli for
increased surface area. This membrane contains sodium-potassium pumps that pump
sodium ions out of the cell and potassium ions into the cell.
These pumps require ATP, so have high amounts of mitochondria surrounding
Large molecules, such as small proteins that may have entered the tubule, will be
reabsorbed by endocytosis.
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43. Questions:
1. Explain what is meant by ultrafiltration?
2. Suggest what might happen if water is not reabsorbed from the nephron
3. Explain why the concentrations of glucose and amino acids are the same in
the glomerular filtrate as in the blood plasma
5/17/2015 43
Filtering on a molecular scale. Small molecules pass through the basement
membrane, which acts as a filter, while larger molecules are held in the
blood
A large volume of very dilute urine would be produced and dehydration would
occur
Because the amino acids and glucose have been passed from the blood
plasma to the glomerular filtrate by ultrafiltration in the glomerulus
45. Reabsorption of Water
Each minute 125cm3 of fluid is filtered from the blood and enters the nephron
tubules
After selective reabsorption in the proximal convoluted tubules about 45cm3
is left
The role of the loop of henle is to create a low (very negative) water
potential in the tissue of the medulla ensures that more water can be
reabsorbed from the fluid in the collecting duct
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46. The Loop of Henle
- Part I
Consists of a descending limb which descends into the medulla and an
ascending limb that ascends back out to the cortex.
The overall effect of the loop of henle:
Filter the fluid entering the descending limb which is slightly concentrated.
Osmotically removing water from the descending limb into the Vasa Recta
Water potential decreases and is highly concentrated as you enter the ascending
limb
Here Na+ and Cl- ions are actively removed from the ascending limb into the Vasa
Recta
The ascending limb is impermeable to water, so cannot leave the tubule.
The ascending limb increases in water potential as it enters the DCT
= COUNTERCURRENT MULTIPLIER
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47. The Loop of Henle
- Part II
Vasa Recta surrounds the loop of
henle in an opposing fashion;
As you go down the descending limb
in the loop of henle you are
ascending in the Vasa Recta, as you
go up the ascending limb in the loop
of henle you are descending in the
Vasa Recta
The top of the ascending limb urine
is highly dilute (watery) therefore as
you continue from the DCT and CT
water is reabsorbed leaving a
concentrated fluid which is excreted
The amount of water reabsorbed
depends on the needs of the body
and so the kidney is also an organ of
osmoregulation.
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48. The Collecting Duct
At the top of the ascending limb it
connects to the DCT which is very
short in comparison to your PCT,
active transport is used to reabsorb
water from your DCT into your
surrounding tissue fluid
From the DCT CD water has a
high water potential therefore the
CD carries on removing water
leaving as it descends from the
medulla into your pelvis.
The remaining solute left becomes
highly concentrated and is
excreted.
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49. Stretching Your Knowledge
Scenario:
Question: Why do camels have humps?
Answer: It was a myth that the hump was due to a long loop of henle.
However current research shows that the hump stores fat which can be
metabolized to release energy and water. But why do camels need an extra
long loop of Henle? All mammals adapted to living in arid regions share this
feature. It provides them with a longer countercurrent mechanism that can
increase the salt concentration in the medulla more than in other mammals.
Task:
Explain why it is beneficial to mammals living in arid regions to have higher
salt concentrations in their medullas?
5/17/2015 49
A higher salt concentration in the medulla means that a greater water potential gradient can be
achieved between the urine in the CD and the medulla. This means that more water can be
reabsorbed from the CD and then pass into blood capillaries and the urine is made more
concentrated. There will be less urine produced and less water lost.
50. Stretching Your Knowledge
Scenario:
The tissue fluid in the medulla has a low water potential, so how can water
pass from the tissue fluid into the blood plasma by osmosis?
Task:
Explain an arrangement of the blood vessels that could create blood plasma
with an even lower water potential than the tissue fluid.
5/17/2015 50
A higher salt concentration in the medulla means that a greater water potential gradient can be
achieved between the urine in the CD and the medulla. This means that more water can be
reabsorbed from the CD and then pass into blood capillaries and the urine is made more
concentrated. There will be less urine produced and less water lost.
51. Questions:
1. Why must the collecting duct pass back through a region of low water
potential?
1. Why is it important for terrestrial mammals to reabsorb as much water as
possible?
2. Suggest why beavers have short loops of Henle
5/17/2015 51
This arrangement allow water to be reabsorbed from the collecting ducts
back into the tissue fluid of the medulla. This concentrates the urine.
Terrestrial mammals gain water by eating and drinking. They lose water
through sweat, exhaling, excretion and egestion. It is important not to lose
more water than necessary, as it may not be readily available.
Beavers live beside or in water. Water is readily available and they do not
need to conserve it as much.
53. Osmoregulation
Osmoregulation = control of water levels and salt levels in the body.
Water is gained from: Food, drink, metabolism
Water is lost in: urine, sweat, water vapor in exhaled air, faeces
When drinking plentiful fluid you will produce a large volume of dilute urine
When drinking a less amount of fluid you will produce smaller volumes of more
concentrated urine
The walls of the collecting duct can be made more or less permeable according to
the needs of the body
On a cool day your requirement of water is lower therefore the walls of the collecting
duct are less permeable and less water is reabsorbed therefore producing more urine
On a warmer day you requirement of water is much more greater therefore the walls of
the collecting duct are more permeable and more water is reabsorbed therefore
producing a smaller volume of urine.
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54. Altering the permeability of the CD
- PART I
The walls of the collecting duct respond to Antidiuretic hormone (ADH) in the
blood.
ADH has an antidiuretic action that prevents the production of dilute urine
(and so is called an antidiuretic)
Cells in the wall have membrane-bound receptors for ADH.
The ADH binds to these receptors and causes a chain of enzyme-controlled
reactions inside the cell.
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55. Altering the permeability of the CD
- PART II
If there is more ADH in the blood then
vesicles containing water-permeable
channels (aquaporins) will fuse into the
cell surface membrane
Therefore, the walls more permeable to
water. More ADH = More permeable
channels inserted more water
reabsorbed by osmosis More
concentrated urine
If there is less ADH in the blood then the
cell surface membrane folds inwards to
create new vesicles that remove water-
permeable channels from the membrane
Therefore, the walls less permeable to
water less water is reabsorbed via
osmosis into the blood more water
passes out into the (dilute) urine.
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59. Adjusting the concn of ADH in the blood
- PART I
The Water potential of the blood is monitored by osmoreceptors in the
hypothalamus of the brain
When water potential of the blood is low the osmoreceptor cells lose water by
osmosis causing them to shrink stimulates neurosecretory cells in the
hypothalamus
The neurosecretory cells are specialized neurons (nerve cells) that produce
and release ADH.
ADH releasing cell bodies are found to lie in the hypothalamus
ADH flows down the axon to the terminal bulb in the posterior pituitary gland
and stored until needed
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60. Adjusting the concn of ADH in the blood
- PART II
When the neurosecretory cells are stimulated they send an AP down their
axons and cause the release of ADH
ADH enters blood capillaries running through the posterior pituitary gland
around the body acts on the cells of the collecting ducts
Once water potential rises, less ADH is released
ADH is slowly broken down and collecting ducts will receive less stimulation –
half-life of about 20minutes
Half-life of a substance is the time taken for it’s concentration to drop to half it’s
original value.
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62. Control of water potential in the blood
by negative feedback
5/17/2015 62
Increase in water
potential of blood
Detected by
osmoreceptors in
hypothalamus
Less ADH released
from the posterior
hypothalamus
Collecting duct
walls less
permeable
Less water reabsorbed
into blood; more
urine produced
Decrease in water
potential of blood
Normal water
potential of blood
Decrease in water
potential of blood
Detected by
osmoreceptors in
hypothalamus
More ADH released
from the posterior
hypothalamus
Collecting duct
walls more
permeable
More water
reabsorbed into blood;
less urine produced
Decrease in water
potential of blood
63. Stretching Your Knowledge
Scenario:
A number of drugs have an effect on urine production. Some have effects that
are unwanted or may be a nuisance. Alcohol inhibits the production of ADH, and
certain antibiotics, such as tetracycline, can cause renal failure through a variety
of mechanisms including direct toxicity to the nephron tubules.
Other drugs have effects that may be useful. Diuretic drugs increase urine
production and antidiuretic drugs do the opposite by increasing the reabsorption
of water at the distal tubule and collecting ducts without significantly modifying
the rate of glomerular filtration.
Task:
Explain why drinking too much alcohol can cause a hangover?
Suggest what symptoms may be relieved by the use of (i) Diuretics and (ii)
antidiuretics
63
Alcohol inhibits the release of ADH therefore the collecting ducts are not very permeable and less
water is reabsorbed. This means that more water is lost in urine and dehydration occurs. The
ethanal produced form the metabolism of ethanol also contributes to the headache
(i) – Diuretic drugs can be used to relieve water retention, which can cause swelling and high
blood pressure.
(ii) Antidiuretic drugs can be used to relieve diabetes insipidus (a form of diabetes caused by a
lack of ADH, resulting in very large amounts of watery urine) and bed wetting.
64. Questions:
1. How do neurosecretory cells differ from normal nerve cells?
1. Explain what is meant by negative feedback?
2. Why is it important that ADH is broken down?
5/17/2015 64
Neurosecretory cells manufacture a hormone in their cell body; this is
transferred down the axon. When it is released it goes straight into the blood
rather than to another nerve cell
Negative feedback occurs when a change in the internal conditions stimulates
a reversal of that change – so the conditions are kept constant
ADH must be broken down so that it is not continually acting on the walls of
the collecting ducts
66. Kidney Failure
Most common causes are:
Diabetes mellitus (both type I and type II sugar diabetes)
Hypertension
Infection
Once the kidneys fail completely the body is unable to remove excess water
and certain waste products from the blood
This includes urea and excess salts.
It is also unable to regulate the levels of water and salts in the body rapid
death
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67. Treatment of Kidney Failure
- PART I
Two main treatments for CKD:
Dialysis (2 subtypes):
most common treatment removing waste, excess fluid from blood by passing the blood
over a dialysis membrane. The membrane is a partially permeable membrane that allows
the exchange of substances between the blood and dialysis fluid.
This fluid contains the correct concentrations of salts, urea, water and other substances in
blood plasma
Any substances in excess in the blood diffuse across the membrane into the dialysis fluid
Any substances that are too low in concentration diffuse into the blood from the dialysis
fluid.
Dialysis must be combined with a carefully monitored diet.
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68. Treatment of Kidney Failure
- PART II
Hemodialysis
Blood from a vein is passed into a
machine that contains an artificial
dialysis membrane. Heparin is
added to avoid blood clotting and
any bubbles are removed before
the blood returns to the body
Hemodialysis is usually performed
at a clinic 3 times a week for
several hours at each sessions, but
some patients learn to carry it out
at home
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69. Treatment of Kidney Failure
- PART III
Peritoneal Dialysis
The filter is the body’s own abdominal
membrane (peritoneum).
First a surgeon implants a permanent
tube in the abdomen.
Dialysis solution is poured through the
tube and fills the space between the
abdominal walls and organs
After several hours, the used solution
is drained from the abdomen.
PD is usually performed in several
consecutive sessions daily at home or
work.
As the patient can walk around having
dialysis, the method is sometimes
called ambulatory PD
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70. Treatment of Kidney Failure
- PART IV
Kidney Transplant
In a kidney transplant the old kidneys are left in place unless they are likely to
cause infection or are cancerous. The donor kidney can be from a living relative
who is willing to donate one of their healthy kidneys or from someone who has
died
A kidney transplant is major surgery. While the patient is under anesthesia,
the surgeon implants the new organ into the lower abdomen and attaches it
to the blood supply and the bladder
Many patients feel much better immediately after the transplant, which is the
best life-extending treatment for kidney failure.
However, the patient’s immune system will recognize the new organ as a
foreign object and produce a reaction
Patients are given immunosuppressant drugs to help prevent rejection
5/17/2015 70
71. Advantages and Disadvantages of Kidney
Transplant
5/17/2015 71
Advantages Disadvantages
Freedom from time-consuming dialysis Need immunosuppressant's for the life of the
kidney
Diet is less limited Need major surgery under a general anesthetic
Feeling better physically Risks of surgery include infection, bleeding and
damage to surrounding organs
A better quality of life i.e. able to travel Frequent checks for signs of organ rejection
No longer seeing oneself as chronically ill Side effects: anti-rejection medicines cause
fluid retention and high blood pressure;
immunosuppressant's increase susceptibility to
infections
72. Testing Urine Samples
- PART I
Substances or molecules with a relative molecular mass of less than 69,000
can enter the nephron. This means that any metabolic product or other
substance that is in the blood can be passed into the urine – as long as it is
small enough.
If these substances are not reabsorbed further down the nephron they can be
detected in urine
Pregnancy Testing:
Once implanted in the uterine lining, a human embryo starts secreting a pregnancy
hormone called human chorionic gonadotrophins (hCG) (Mr. = 36,700)
It can be found in urine as early as 6 days after conception. The pregnancy tests on
the market today are manufactured with monoclonal antibodies.
Antibody is specific, it will only bind to hCG, not to other hormones.
5/17/2015 72
73. Testing Urine Samples
- PART II
When someone takes a home pregnancy test, she soaks a portion of the test strip
in her urine.
Any hCG in the urine attaches to an antibody that is tagged with a blue bead
This hCG-antibody complex moves up the strip until it sticks to a band of
immobilized antibodies
As a result all the antibodies carrying a blue bead and attached to hCG are held in
one place forming a blue line
There is always one control blue line to use for comparison; a second blue line
indicates pregnancy
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75. Testing Urine Samples
- PART III
Testing for anabolic steroids:
Anabolic Steroids – increase protein
synthesis within cells build-up of
cell tissues especially in the muscles
Non-medical uses for anabolic
steroids are controversial because
they can give advantage in
competitive sports and they have
dangerous side effects (use in sports
is now banned)
Half-life of about 16 hours and
remain in the blood for many days.
Relatively small molecules and enter
the nephron easily
5/17/2015 75
76. Testing Urine Samples
- PART IV
Testing for anabolic steroids involves
analyzing a urine sample in a laboratory
using gas chromatography or mass
spectrometry
In a gas chromatography the sample is
vaporized in the presence of a gaseous
solvent and passed down a long tube
lined by the absorption agent
Each substances dissolves differently in
the gas and stays there for a unique,
specific time, the retention time.
Eventually the substances comes out of
the gas and is absorbed onto the lining
detector creates a chromatogram
Standard samples of drugs, as well as
the urine samples are run so that the
drugs can be identified and quantified in
the chromatograms
5/17/2015 76
77. Questions:
1. What components of the diet must be carefully monitored in someone who
undergoes dialysis
2. Explain why hemodialysis fluid has to be sterile and at 37oC
3. Create a table of advantages and disadvantages of dialysis as a treatment for
kidney failure
4. Explain why standard samples of drugs must be run alongside a urine sample
in gas chromatography
5/17/2015 77
79. Module Summary:
1.2.1 – Excretion
Key Definitions:
Excretion removal of metabolic waste form the body
Metabolic waste consists of waste substances that may be toxic or are produced in
excess by the reactions inside cells
Deamination removal of an amine group from an amino acid to produce ammonia
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80. Module Summary:
1.2.2 – The Liver
Key Definitions:
Hepatic Portal Vein unusual blood vessel that has capillaries at both ends – it carries
blood from the digestive system to the liver
Function of Kupffer cells appears to be the breakdown and recycling of old red blood
cells. Bilirubin is ne of the waste products from the breakdown of hemoglobin
5/17/2015 80
81. Module Summary
5/17/2015 81
1.2.3 – Functions of the Liver
Key Definitions:
Urea excretory product formed from the breakdown of excess amino acids
Ornithine cycle the process in which ammonia is converted to urea. It occurs partly in
the cytosol and partly in the mitochondria, as ATP is used
Detoxification – conversion of toxic molecules to less toxic or non-toxic molecules
82. Module Summary:
1.2.4 – The Kidney
Key Definitions:
Nephron the functional unit of the kidney. Microscopic tubule that receives fluid from
the blood capillaries in the cortex and converts this to urine, which drains into the ureter
Glomerulus fine network of capillaries that increases the local blood pressure to
squeeze fluid out of the blood. It is surrounded by a cup-or funnel-shaped capsule which
collects the fluid and leads into the nephron
In selective reabsorption useful substances are reabsorbed form the nephron into the
bloodstream while other excretory substances remain in the nephron
The PCT is the closest to the Glomerulus / The DCT is the furthest from the
glomerulus
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83. Module Summary:
1.2.5 – Formation of Urine
All organs have afferent vessels – they bring blood into the organ. Similarly, efferent vessels carry blood away
from the organ. In a glomerulus the efferent vessels is an arteriole – which is muscular and can constrict to
raise the blood pressure in the glomerulus. In most organs a venule carries blood away
Ultrafiltration is filtration at a molecular level – as in the glomerulus where large molecules and cells are left
in the blood and smaller molecules pass into the Bowman’s capsule
Podocytes are specialized cells that make up the lining of the Bowman’s capsule
TIP: the endothelium of the capillary and the epithelium of Bowman’s capsule contains gaps or pores. These two
layers of cells do little to filter out larger molecules. IT is the basement membrane that is actually involved in
ultrafiltration
Key Definitions:
Microvilli are microscopic folds of the cell surface membrane that increase the surface area of the cell
Co-transporter proteins are proteins in the cell surface membrane that allow the facilitated diffusion of simple
ions to be accompanied by transport of a larger molecule such as glucose
Facilitated diffusion is diffusion that is enhanced by the action of proteins in the cell membrane
Sodium-Potassium pumps are special proteins in the cell surface membrane that actively transports sodium and
potassium ions against their concentration gradient
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84. Module Summary:
1.5.6 – Water reabsorption
Key definitions:
A hairpin countercurrent multiplier is the arrangement of a tubule in a sharp hairpin so
that one part of the tubules passes close to another part of the tubule with the fluid
flowing in opposite directions. This allows exchange between the contents and can be
used to create a very high concentration of solutes
Osmoregulation is the control and regulation of water potential of the blood and body
fluids. In humans the kidney controls the water potential of the blood
The distal convoluted tubule is the coiled portion of the nephron between the loop of
henle and the collecting duct.
5/17/2015 84
85. Module Summary:
1.5.7 – Osmoregulation
Key definitions:
Antidiuretic Hormone (ADH) is released from the pituitary gland and acts on the
collecting ducts in the kidneys to increase their reabsorption of water
Osmoreceptor are receptor cells that monitor the water potential of the blood. IF the
blood has a low water potential then water is moved out of the osmoreceptor cells by
osmosis, causing them to shrink. This causes stimulation of the neurosecretory cells
Hypothalamus is part of the brain that contains neurosecretory cells and various receptors
that monitor the blood
Neurosecretory cells are specialized cells that act like nerve cells but release a hormone
into the blood. ADH is manufactured in the cell body and passes down the axon to be
stored in the terminal bulb. If an action potential passes down the axon then ADH is
released from the terminal bulb
Posterior pituitary gland is the hind part of the pituitary gland, which releases ADH.
5/17/2015 85
86. Module Summary:
1.5.8 – Kidney Failure
Key Definitions:
Human chorionic gonadotrophins (hCG) is a hormone released by human embryos; it’s
presence in the mothers urine confirms pregnancy
Monoclonal antibodies are identical because they have been produced by cells that are
clones of the original cell
Anabolic steroids are drugs that mimic the action of steroid hormones that increase
muscle growth
Gas chromatography is a technique used to separate substances in a gaseous state. A
Chromatogram is a chart produced when substances are separated by movement of a
solvent along a permeable material such as paper or gel
5/17/2015 86
87. Thank you, feel free to ask for any
help.
By Piril Erel
5/17/2015 87