Unit 2 The Circulatory System

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Unit 2

The Circulatory System

The role of the cardiovascular system and its key organs.

That blood is a moving tissue containing blood cells, oxygen, carbon dioxide, nutrients, hormones and waste products.

The role of red blood cells and how haemoglobin aids oxygen transport.

The anatomy and function of the heart as a four chambered pump.

The role of arteries, veins and capillaries.

The heart cycle including systole and diastole.

What lifestyle factors contribute to the development of arthrosclerosis and the key events of a heart attack.

That the genetic blood disorder, sickle cell anaemia affects oxygen transport to cells.

How maintaining fitness leads to a healthy body.

The clotting response and scab formation.

The role of white blood cells, platelets and antibodies in protecting us against infection by bacteria and viruses.

Blood, Tissue, Red blood cells, White blood cells, Platelets, Antibodies, Cardiovascular, System, Heart, Arteries, Capillaries, Veins, Oxygen, Transport, Systole, Diastole, Haemoglobin, Microbes, Bacteria, Viruses, Disease, Scab, Immunity, Lymphocytes, Neutrophils, Clotting, Antibodies, Vaccines, Vaccination & Arthrosclerosis. Unit 2: The Circulatory System Science Interactive LTD Copyright 2005 Click mouse to begin Understand: Keywords:

The cardiovascular system The cardiovascular system, like any other organ system is a collection of specialised cells, tissues and organs. Its role is to transport useful substance like o________, amino acids and glucose to respiring tissues whilst removing waste substances like c______ dioxide and urea. Your blood also transports hormones produced by the endocrine glands, for example adrenalin. W______ blood cells, antibodies and platelets are also transported by the blood and help prevent infection caused by viruses and bacteria. Why does a unicellular organism like an Amoeba not need a cardiovascular system ? Overview of the cardiovascular system: Science Interactive LTD Copyright 2005 Word bank: oxygen carbon white The heart continuously pumps blood around the body, beating around 70 times a minute for almost 80 years. It is an incredible example of bio-engineering. Heart The cardiovascular system is the human body’s transport system. It moves oxygen, carbon dioxide, nutrients, hormones and immune cells around a network of tubes. Cardiovascular system Blood vessels range from almost 1 cm in diameter to a fraction of a millimetre. There are over 50,000 km of blood vessels in the human body. Red and white blood cells are transported around the body by network of tubes. These cells are made in the soft marrow of the long bones. Notes Diagram Blood cells Blood vessels

Your blood The human body has about five litres of blood which is continuously p______ around a network of arteries, capillaries and v______. Blood is a moving, liquid tissue that contains many types of cells, each which a unique function. Red blood cells transport oxygen around the body. White blood cells help fight disease. P________ are cell fragments which help scabs to form to prevent bleeding and microbial infection after injury to the skin. The yellow liquid called plasma transports nutrients like glucose and waste products like carbon dioxide and urea. How would you separate the yellow plasma from the red and white blood cells ? Human blood: Science Interactive LTD Copyright 2005 Word bank: pumped veins platelets Plasma can also be given during surgery or following dehydration. Plasma contains salts, water, nutrients like sugar and amino acids and hormones like adrenalin. Blood plasma One of the specialised cells of blood is the red blood cell or erythrocyte. It is highly specialised to transport oxygen around the many arteries veins and capillaries. Blood cells Blood transfusions are often performed during surgery or after a major accident. Blood is vital for life and needs to be replaced quickly if lost. An average human has five litres or eight pints of blood circulating around the body. When you donate blood, doctors only take one pint or half a litre. Notes Diagram Blood volume Transfusions

Red blood cells and their function There are over four million red blood cells in every mm 3 of blood. Their function is to transport o_________ from the l______ surface, through the capillary network to every living cell in your body. Red blood cells are well designed to transport oxygen, having no n_________ and a dumbbell shape to increase s_________ area. They are also rich in haemoglobin, which binds oxygen during its transport from the lungs around the entire body. How does having no nucleus help red blood cells to transport oxygen ? Red blood cells: Science Interactive LTD Copyright 2005 Word bank: oxygen lung nucleus surface Plasma Platelets Red blood cells Red blood cell Red blood cells contain a red pigment called haemoglobin. They have no nucleus and are biconcave in shaped to help transport oxygen around the body. Red blood cells Red blood cells are rich in the protein haemoglobin and iron, which transport oxygen from the lung surface to billions of respiring cells in the human body. Haemoglobin Over half the liquid in blood is clear plasma. Nutrients from the digestive system are dissolved in plasma as well as waste products like urea. A single drop of blood contains many millions of red blood cells. This represent just under half the total number of cells found in human blood. Notes Diagram What's in blood Blood plasma

Other components of blood White blood cells are larger than r____ blood cells, but there are fewer of them. For every one white blood cell there are over 500 red blood cells. Their main function is to protect the body against m_______ infection. There are two main types of white blood cells. Lymphocytes produce antibodies which bind bacteria and viruses before there are engulfed by the other type of white blood cell, neutrophils . Platelets, which are not whole cells, help scab formation when you cut your skin. This prevents further blood loss. What is the disease called when your blood fails to clot ? Other components of the blood: Science Interactive LTD Copyright 2005 Word bank: red microbial lymphocytes neutrophils Platelets are not true whole cells, but cell fragments. When you cut yourself, platelets help scab formation preventing further blood loss and microbial infection. Platelets If you analyse your blood, you will also find dissolved in the plasma nutrients like glucose, amino acids, fatty acids and glycerol, which are the products of digestion. Hormones are also transported from their site of production to their target tissues. Other blood components Both lymphocytes and neutrophils are part of the immune system. They roam the body and ‘search and destroy’ any invading microbes (bacteria & viruses.) Lymphocyte cells produce antibodies which help clump bacteria together so they can be engulfed by neutrophils. Notes Diagram Lymphocytes & neutrophils

Arteries, veins and capillaries The heart does not work alone to deliver oxygen and n_______ to the entire body. Blood is pumped around a highly complex system of blood vessels measuring over 50,000 km in the average human. There are three types of blood vessels: Arteries, Veins and Capillaries . Arteries carry blood at the highest pressure away from the h_____ and therefore have the thickest elastic muscle wall of all of the different types of blood tubes. From the descriptions below describe any similarities of differences ? Blood tubes of the cardiovascular system: Elastic fibres Outer wall Thick muscle Outer wall Valve Thin muscle Elastic fibres Science Interactive LTD Copyright 2005 Word bank: nutrients heart Arteriole Venule Capillaries Veins carry blood towards the heart under low pressure. They have a thin muscle and elastic layer and valves which prevent blood flowing backwards. Blood flow back towards your heart is also helped by your skeletal muscles. Veins Fine capillaries cover the human body in a network of tubes. These capillaries are extremely thin and narrow, measuring over 50,000 km in the human body. You need a microscope to see capillaries. Arteries carry blood away from the heart under high pressure. They have a thick muscle and elastic layer which stretch every time the heart beats. They contract back and force blood forwards. This can be felt as your pulse ! Arteries Capillaries

Blood cells at the capillary Blood capillaries have a very small d______ allowing only one red blood cell through at a time. Blood flows very slowly through your capillaries. The capillaries are extremely thin walled, which allows o______ and plasma which contains nutrients to diffuse to the tissue bed and cells. Also waste products like urea and carbon dioxide can pass from the cells back to the capillary. Why are red blood cells unable pass through the capillary walls ? Understanding your capillaries: Oxygen Glucose Amino acids Water Carbon Urea Wastes dioxide Net pressure Cells Science Interactive LTD Copyright 2005 Word bank: diameter oxygen Oxygen and nutrients including glucose diffuse from the blood, across the capillary wall to the cells. These are used for cellular respiration. Waste products including carbon dioxide and urea are transported back in the plasma for transport to the lungs and kidneys. An electron micrograph of a single capillary. Notice the narrow diameter allowing only one blood cell through. Notes Diagram Blood capillaries Gaseous and nutrient exchange at the capillary bed

Blood circulation The circulation of blood through the heart, lungs and other major organs keeps the human body supplied with the o______ and nutrients that it requires for cellular respiration, growth and repair. This transport system also carries the white blood cells, platelets and antibodies around the body defending us against microbial infection. What lifestyle factors can prematurely age your cardiovascular system ? Circulation in the body: Science Interactive LTD Copyright 2005 Word bank: oxygen Oxygen is exchanged for carbon dioxide at the tissue surface. Oxygen diffuses across the capillary wall into the cells or tissue. Oxygen is combined with glucose during cellular respiration. Waste products including carbon dioxide and urea are transported in the plasma to the lungs and the kidneys. Capillary exchange in detail O 2 O 2 O 2 O 2 CO 2 CO 2 Tissue Red Blood Cell Red Blood Cell

Oxygen transport by blood haemoglobin Red blood cells contain the protein, haemoglobin which is responsible for binding oxygen at the l______ tissue (alveoli) and delivering it to every r____________ tissue or cell via a huge capillary network which can be up to 50,000 km in length in the human body. Haemoglobin also contains the mineral i_____ to help oxygen transport. Why is iron important in the diet and why do females require greater quantities of this mineral ? Oxygen transport: Science Interactive LTD Copyright 2005 Word bank: lung respiring iron CO 2 O 2 O 2 CO 2 O 2 O 2 O 2 CO 2 O 2 O 2 Haemoglobin Oxyhaemoglobin Haemoglobin is a protein found in the red blood cell. It contains Iron (Fe 2+ ) and is able to bind oxygen at several sites. Why do females require more iron than males ? Haemoglobin Oxygen diffuses across the thin capillaries walls to the cells. It travels form a high concentration inside the capillary to a low concentration. Carbon dioxide moves to the blood. In the tissues Air contains 21% oxygen which is taken to the alveoli tissue by the bronchioles. Oxygen dissolves across the thin alveoli surface and binds to red blood cells found inside the lung capillaries. Notes Diagram At the alveoli

The human heart The heart, a four chambered pump is a collection of s__________ tissues which work together to pump blood to the lungs, picking up oxygen and excreting carbon dioxide and then to the body delivering oxygen and nutrients to every respiring cell, via a network of arteries, veins and capillaries. The ventricles create sufficient p_________ by squeezing to send blood either to the lungs (right ventricle) or the rest of the body (left ventricle) A number of valves between the connecting chambers stops any unwanted backflow of blood. Why is the left ventricle thicker than the right ventricle ? Main features of the human heart: Science Interactive LTD Copyright 2005 Word bank: specialised pressure The difference in blood pressure in the arties and veins allows blood to flow around the body. This pressure is created by the ventricles contracting. Blood pressure Valves between the four chambers (Atria and Ventricles) open and close to prevent blood from being forced backed when the ventricles contract. The human heart is about the size of a adult fist. Its function is to pump blood to the lungs (RA, RV) and to the rest of the body (LA, LV). Look at the picture of the four chambers. Notes Diagram Human heart Heart valves

The heart cycle one If you look at the diagram below and follow the arrows, you can trace the path of blood around the heart. Deoxygenated blood flows from the b_____, entering the right atria. It then travels to the right ventricle where its is pumped to the l______ to pick up oxygen and excrete carbon dioxide. Oxygenated blood enters the left atria, where it travels to the left ventricle. Here blood is pumped to the rest of the body via the aorta. Circulation around the heart: Lungs Science Interactive LTD Copyright 2005 Word bank: body lungs 1 2 3 5 4 6 The diagram above shows the structure of the human heart. The pumping action of your heart is produced by the muscle walls of the left and right ventricles. When the ventricles contract, blood is squeezed at pressure into the arteries that supply the lung or the entire body. The valves only allow blood to flow in one direction. Draw a flow diagram to help explain how blood is pumped around your lungs and body ? Blood delivers oxygen and nutrients to all cells. Blood is forced through the largest artery and into the blood. Blood moves into the left ventricle. Oxygenated blood enters the heart into the left atrium. Blood loses carbon dioxide and picks up oxygen. Right ventricle contracts and pumps blood to the lung. Deoxygenated blood enters the heart into the right atrium. Action (Draw numbered arrows on the diagram) Arrow

The heart cycle two The heart is supplied by electrical impulses through the vagus nerve . At rest, the heart beats approximately 72 beats per minute (b.p.m.) When we e_________, our heart rate increases to supply the exercising muscles with additional oxygen and nutrients. In a trained athlete what are the differences in how their hearts perform during exercise ? The heart cycle: Science Interactive LTD Copyright 2005 Word bank: exercise The beating cycle of the heart lasts just under a second. It is controlled by the vagus nerve. If we monitor the electrical activity of the heart it gives a typical profile as shown left. The peak electrical activity triggers the contraction of the left ventricle, the largest ventricle which forces oxygenated blood around the body. Notes ECG Diagram Four Three Two One Stage

Understanding blood pressure Blood pressure is caused by the ventricular muscles contracting during every heart cycle. This pressure forces blood through the vast network of arteries, capillaries and veins. High blood pressure, caused by narrowed arteries and high salt diets can damage your vascular system and in extreme cases, lead to a heart a______. Blood pressure in humans: Pressure (mmHg) Science Interactive LTD Copyright 2005 Word bank: attack Two Four You can take your blood pressure. A normal adult should have a reading of 120/80 (mmHg) Blood pressure Notes Diagram One Three

The heart and aerobic respiration If you view animals cells under a m__________, you can see tiny dots in the cytoplasm. These are mitochondria. Cellular respiration occurs in the mitochondria, releasing energy from the breakdown of glucose using oxygen. All living things give out carbon dioxide, a waste product of cellular respiration. It is the role of the heart to supply sufficient oxygen to and remove waste carbon dioxide from all cells in the Human body. Respiration and mitochondria: Science Interactive LTD Copyright 2005 Word bank: microscope C 6 H 12 O 6 6O 2 6CO 2 6H 2 O Cells Mitochondria Energy Body temp ( o C) Nerve messages Building cells Digestion Diagram Use Muscles Transport Diagram Mitochondria Cellular respiration is the breakdown of glucose with oxygen providing cellular energy. This happens in the cell’s mitochondria. Cellular respiration equation: C 6 H 12 O 6 + 6O 2 6H 2 O + 6CO 2 Glucose Oxygen Water Carbon dioxide Notes

Oxygen debt during anaerobic respiration When muscles are working hard, they begin to respire glucose without oxygen. This is called anaerobic respiration . Lactic acid produced during anaerobic respiration builds up and slowly poisons your muscles. When your body can’t supply sufficient oxygen to your muscles, this is called oxygen debt . When you stop vigorous exercise, your heart and lungs continue to supply extra oxygen to allow the muscle to breakdown l____ acid. This repays the oxygen debt. Oxygen debt: A B C Science Interactive LTD Copyright 2005 Word bank: lactic a b c Time (Minutes) Oxygen supply (litres) Oxygen demand (litres) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Oxygen supply Oxygen demand Oxygen debt 0 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 0.25 0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5 0 C 6 H 12 O 6 Carbon dioxide Sugar acid 6O 2 Lactic During anaerobic respiration, less energy is produced respiring glucose without oxygen. Lactic acid builds up and begins to damage your muscles, giving you the sensation of the ‘burn.’ Lactic acid production in muscle Notes Diagram During rest (a) the supply of oxygen to the muscles meets demand. During hard vigorous exercise (b) , demand increases above supply and the muscle have to continue respiring glucose without oxygen. Anaerobic respiration leads to the oxygen debt and formation of lactic acid. This oxygen debt is repaid when exercise stops (c) by the lungs continuing to oversupply the muscles with the lungs. Oxygen debt in muscles

Complete fitness Athletes require their key organ systems to work together so that they can exercise and play their sport. Fitness is a measure of how well you body w_____ and exercises. Athletes require ‘total fitness’ so that they can win and excel at their s______. The cardiovascular, respiratory and skeletal-muscle system all work together to supply the oxygen and nutrients to your muscles. How would you devise a training programme to increase your overall fitness ? Essential organ systems: Science Interactive LTD Copyright 2005 Word bank: works sport The skeletal-muscle system works to move the body during sport. An elite sprinter requires the fastest contracting muscles during a 100 m race. Muscle Your respiratory system is constantly working to exchange oxygen for carbon dioxide between the alveoli and the pulmonary capillaries in the lung. Respiratory Notes Diagram Professional athletes like runners and footballers work hard to be fit for their sport, but ideas of fitness vary according to their sport. Athlete The cardiovascular system is the human body’s transport system. It moves oxygen, carbon dioxide, nutrients, hormones, and immune cells around a network of tubes. Cardiovascular

Maintaining fitness Athletes work hard to achieve total fitness, but what does being fit mean ? If you are fit, you will have a low resting heart rate which recovers quickly after e_________. Your lungs efficiently exchange oxygen and carbon dioxide at the alveoli tissue and your skeletal m________ system moves you quickly, without tiring during a race or a game. Exercising ( running, weights & gym work ) helps us to achieve fitness and improve our ability to compete and win. Fitness and the five ‘S’ Science Interactive LTD Copyright 2005 Word bank: exercise muscle Notes The five ‘S’ strength, stamina, skill, suppleness and speed are all improved by repetitive training and exercise. Regular exercise also helps prevent people becoming overweight and developing heart disease and diabetes. Nearly 25% of all adults are now considered obese with almost 50% of all pupils of secondary school age not taking enough exercise. Suppleness Speed Skill Diagram Strength Stamina

Atherosclerosis and heart disease A high f____ diet over many years, lack of e__________, too much alcohol and smoking leads to arthrosclerosis and general heart disease. Arthrosclerosis reduces the diameter of the aorta and other major arteries, therefore increases blood p_______. Eventually a heart attack may follow because of a clot in the coronary arteries. How can we educate people to reduce their risk of developing atherosclerosis ? Atherosclerosis: Science Interactive LTD Copyright 2005 Word bank: fat exercise pressure smoking The heart starved of oxygen suffers a heart attack. Fatty deposits block veins and arteries reducing blood flow. Healthy arteries allow red blood cells to flow freely through the heart tissue. All these risk factors contribute to heart disease. Notes

Alcohol

S________

Drugs

No exercise

Atherosclerosis Smoking Heart attack Exercise Normal Veins or Arteries Risk factors Process Diagram Factor Alcohol Drugs

Understanding heart attacks During a heart attack, the arteries supplying the heart and its muscular ventricles become blocked with f______ deposits that have become detached from the lining of the coronary arteries. Any heart muscle ‘downstream’ of the blockage is starved of o_______ and dies. The heart can withstand losing about 50% of its muscle function. A fatal heart attack is where the blockage deprives over 50% of heart muscle of their essential oxygen and nutrients. What ‘lifestyle factors’ increase the risk of a heart attack ? Heart attack: Science Interactive LTD Copyright 2005 Word bank: fatty oxygen If your coronary arteries become blocked, you can opt for a triple bypass, where veins from your leg replace the blocked arteries supplying the heart. Heart bypass A final option, if the heart becomes damaged beyond repair, is to have a mechanical heart. Post operative survival rates for this procedure are relatively low. Mechanical heart During a heart attack, the muscle tissue is starved of oxygen and nutrients because of a blockage in the coronary arteries. The muscle tissue then dies. A high fat diet may lead to fatty deposits blocking your arteries. These can break free causing a blockage in the arteries supplying the heart. Notes Diagram Blocked arteries Heart attack

Sickle cell anaemia Sickle cell anaemia is a genetic disease of the blood that affects African populations. The disease is passed through faulty genes carried by the paternal s_____ or maternal eggs. In humans who have the disease, red blood cells are sickle shaped with a reduced s_________ area, which reduces the amount of o________ carried to the cells and tissues. This disease is normally fatal. How can genetic counselling help parents and families who carry the faulty gene for sickle cell anaemia make choices when having children ? Sickle cell anaemia: Science Interactive LTD Copyright 2005 Word bank: sperm surface oxygen O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 O 2 Oxygen O 2 O 2 O 2 O 2 O 2 Oxygen Oxygen Oxygen Normal cell Sickle cell Faulty genes inherited from one or both parents cause sickle cell disease. The surface area of the sickle cell is reduced. Sickle cell Less oxygen than normal reaches the tissues and cells. The sickle shaped red blood cells are not able to carry sufficient oxygen because of their reduced surface area. Oxygen transport Normal red blood cells have no nucleus and are biconcave in shape to help transport oxygen around the body. Notes Diagram Normal blood

Disease causing microbes Bacteria, v_________ and fungi are all microbes which are able to cause disease in humans. Not all diseases are caused by microbes, for example heart disease is caused by a number of lifestyle factors like a high fat diet, smoking or excessive a________ intake. Microbes can be found anywhere, in the air, the soil, on food, or on unclean surfaces and in water. A particular risk of infection is associated with sharing unclean needles. Blood born viruses like HIV and hepatitis can be passed on from person to person. Why are intravenous drug users who inject drugs like heroin or crack at particular risk at contracting viruses like HIV and hepatitis? Microbes: Science Interactive LTD Copyright 2005 Word bank: viruses alcohol Some types of fungi can cause disease or infections in humans. Athlete’s foot is caused by a fungi. They reproduce by producing spores. Fungi Blood borne viruses including HIV and hepatitis can be passed from person to person by needle sharing. Drug users have a high risk of contracting HIV. Needles Viruses are extremely small. Viruses are not whole cells. Their genes are found in a protective protein coat. They reproduce inside other cells. A bacteria is a single celled organism. All the bacteria in the world weigh more than any other class of species. They are the most successful species. Notes Diagram Bacteria Viruses

Transmission of bacterial disease one Bacteria can be found in every living o_________, on every surface and even in the air we breathe. Some bacteria are very useful, whilst other cause diseases like cholera and dysentery. There are a number of ways in which bacteria can enter your body. By understanding how disease enters our body, we can reduce our risk of contracting or spreading the disease. Explain why most infections caused by bacteria are entirely avoidable in humans ? Bacterial infecting people: Science Interactive LTD Copyright 2005 Word bank: organism Water containing human waste is full of bacteria. Before water is fit to drink it is filtered, cleaned and sterilised using chlorine which is antiseptic. Sewage Surfaces in kitchens and bathrooms can be home to many thousands of unwanted and harmful bacteria. Always keep these surfaces clean by using disinfectants. Touching an infected person can lead to the transmission of the disease causing bacteria. Bacterial infections causing nausea can be spread by touch. Fresh food and drink can be infected with bacteria. Some foods contain bacteria that can only be destroyed by cooking. How does this destroy bacteria ? Notes Diagram Food Touching Surfaces

Transmission of bacterial disease two Bacteria has to enter our bodies before they can cause d________. They can enter via the digestive system, the nose or cuts in our s____. Our lifestyles determine our risk to infection. In refugee camps, where there is little or no treatment of sewage, poor nutrition and many people living in unsanitary conditions, disease spreads rapidly killing many people. We all have a personal responsibility for how we live and how clean we are. Explain how modern intensive farming can lead to the transmission of viruses like ‘bird flu’ or ‘mad cows disease: BSE ’ in humans ? Bacteria infecting people: Science Interactive LTD Copyright 2005 Word bank: bacteria skin Using a tissue and covering your nose prevents you from infecting other people. Millions of microbes are expelled from your nose every time you sneeze. Sneezing Human waste is another source of bacterial infection. Decaying fruit, meat and vegetables play host to many different bacterial colonies. Why do we treat our waste ? Washing your hands before meals or after going to the toilet reduces the risk of infection from bacteria found in human waste like faeces. Animals are a potential source of infection. Most farm raised animals are given huge amounts of antibiotics to control their levels of disease and bacteria. Notes Diagram Animals Washing hands Waste

Human immunity You can have two types of immunity: Innate and acquired immunity. Innate immunity is your body’s response to an i_________. When you are infected by a microbe, your white blood cells will respond by engulfing the microbes and produce the right sort of antibodies. Acquired immunity can come from vaccinations, breast feeding or booster jabs. During breast feeding, your mother’s milk contains a__________ which can help you fight any disease until your own immune system develops. Can you remember any of the vaccinations that you have been given ? Types of immunity: Science Interactive LTD Copyright 2005 Word bank: infection antibodies Blood Plasma Cells Neutrophils Lymphocytes Red Blood Cells Breast feeding Boosters We can acquire immunity in three ways: During vaccination, vaccines are given to us when we are young to protect us against diseases like smallpox. Breast feeding allows the newborn to have all the same antibodies as their mothers. Boosters are given when there is an outbreak of a disease or to the young and old. These are given by injection. White blood cells find and destroy microbes, reducing our risk of dying from infection. Although less numerous than red blood cells, there are an essential part of our immune system. Notes Diagram Innate immunity Vaccination

Blood fighting infection one Blood also contains white blood cells, platelets and antibodies that are all part of the immune system which is responsible for fighting disease. White blood cells are a collection of cells that help recognise, fight and destroy foreign material like b________ and viruses. Lymphocytes produce antibodies which help clump bacteria together so they can be engulfed by neutrophils (also called phagocytes) When a new m_________ enters the body, new antibodies are made which recognise only that microbe. After the microbe has been destroyed, these antibodies remain in the blood, giving you immunity to that microbe. Why do babies have the same immunity as their mothers ? Immune response in blood: Science Interactive LTD Copyright 2005 Word bank: bacteria microbe Antibodies produced by lymphocytes in response to a specific microbe are able to recognise and clump together these invaders. It takes about 2 – 5 days for lymphocytes to make these antibodies. Stage three Phagocytes or neutrophils begin to search, and destroy microbial cells. They release enzymes which rip open and destroy the microbes. They also neutralise any microbial toxins. Stage four Microbes use the blood and other tissues to begin to multiply. They have a ready source of oxygen and nutrients. If the microbes continue to multiply, the toxin they produce would kill you. Microbes enter your body from sources like unclean hands or food that has not been cooked or handled properly. Describe four other ways of microbial transmission ? Notes Diagram Stage one Stage two

Blood fighting infection two The skin is the largest o______ in the body. One of its main functions is to act as a ‘physical barrier’ to the entry of microbes. If cut, you are at risk of infection caused by the entry and subsequent multiplication of microbes in the circulatory system. Once cut, the skin rapidly heals to prevent further blood loss and the entry of microbes into the b______ stream. Healing and scab formation is helped by the clotting response. This is where platelets and fibrinogen, both carried in the blood, form a tightly knitted scab that closes the wound. What role do plasters play in helping us avoid infection from microbes ? Forming a scab: Science Interactive LTD Copyright 2005 Word bank: organ blood Stage two Stage three When you cut healthy skin, a three stage response occurs before scab formation takes place. One: The skin is cut, bleeding occurs. Two: Platelets are pumped to the injury site. Three: Platelets and fibrinogen form a scab which prevents further bleeding and closes the wound. White blood cells are also rushed to the injury site to destroy what ? A key role of the skin is to help maintain core body temperature at 37 o C. The skin also has many other roles. It protects your body against disease and bacterial infection by acting as a physical barrier Notes Diagram Human skin Stage one

Blood fighting infection three White blood cells (neutrophils) constantly roam around the circulatory system. Unlike red blood cells, they do not carry o_______, but form part of your immune system. Neutrophils are able to find, attach and engulf m_______. When the invading microbes are fully engulfed, they are digested and destroyed by enzymes inside the cell. These white blood cells are also able to neutralise any microbial toxins, therefore preventing these toxins from poisoning your body. HIV affects your white blood cell count...how does this leave you vulnerable to other diseases ? Neutrophils engulfing bacteria: Science Interactive LTD Copyright 2005 Word bank: oxygen microbes Blood Plasma Cells Neutrophils Lymphocytes Red Blood Cells Images of a neutrophil (phagocyte) in action. They have long thread like features which literally trap the bacteria and draw them in to be engulfed by the neutrophil. HIV destroys these cells ! Neutrophils (Phagocytes) in action An essential role of blood is to fight disease. Lymphocyte antibodies and neutrophils search and destroy microbes. Without an immune system we couldn't survive in our environment. Notes Diagram Components of the blood

Blood fighting infection four Despite millions of neutrophils, which search and destroy microbes that enter the bloodstream, some microbes are difficult to find and evade detection by these immune cells. The other white blood cells, lymphocytes produce a__________ which are specific to an individual microbe. They work by binding onto the surface of the microbe and clumping them together. This makes their detection by neutrophils easier. Your body also remembers this microbe and continue to produce antibodies for the rest of your life, ready for the next time. Why do they say that you never catch the same cold twice ? Antibodies in your blood: Science Interactive LTD Copyright 2005 Word bank: antibodies Antibodies are able to clump together microbes in the blood by binding themselves to the their surface. This aids their detection by neutrophils which then destroy them. How antibodies work Several days after infection, your lymphocytes start to produce large numbers of antibodies which roam around the bloodstream looking for invading microbes. Bacteria enter and multiply in the blood. They spread out and try to avoid detection by your neutrophils. What happens if they are left to continue to multiply in the bloodstream ? Notes Diagram Bacterial infection Producing antibodies

Microbes and your health When microbes like viruses or bacteria enter your body, you develop s_________ alongside the disease. These symptoms are a result of either toxins produced by rapidly multiplying bacteria or viruses destroying your cells found in organs like your lung. Your body temperature rises, you may feel generally unwell, sleepy and experience a____ or pains. During the illness period, your body begins to make new antibodies and neutrophils to search and destroy the microbes. Look at the graph and see how you body responds to illness or disease caused by microbes. Microbes and your health: Science Interactive LTD Copyright 2005 Word bank: symptoms aches Measurements of body temperature, microbes and antibody levels were taken during a 14 days period. 1: How long would you have felt ill during the 14 days ? 2: How many days did the microbe replicate itself in the body before your immune system kicked in ? 3: Why did the number of microbes start to decrease after 5 days ? 4: Explain why the level of antibodies in your blood remain high, even during recovery ? Notes

Define the following terms: Blood, Immunity, Microbe, Bacteria, Virus, Fungi, Immunity, Antibodies & Vaccine.

Look at the diagram of the three types of microbes. Complete the table.

Name three cells types contained in the blood and give a function for each. What’s the role of the clear plasma fluid found also in blood.

Using the diagram of the circulatory system answer the following questions: (a) Which blood vessels carry blood away from the heart. (b) Which blood vessels carry blood to the heart. (c) Name the blood vessel through which blood enters the heart from the body (d) Describe the path blood takes from the lung surface to the liver.

Complete the following table:

Extension questions and homework Science Interactive LTD Copyright 2005 Carries blood to the heart. Has a _____ wall carrying blood at ______ pressure. Contains valves to stop back flow. Connects arteries and _______. Has a _____ wall and carries blood at _____ pressure to allow gas exchange. Carries blood ___ the heart. Has a ______ wall carrying blood at ______ pressure. The aorta is the biggest example. Veins Capillaries Arteries How are they spread Fungi Viruses Bacteria What symptoms do they produce Examples Microbe

6: Look at the information in the table below. It shows the patient’s temperature when suffering from a bacterial infection: a) What symptom of the disease is shown by the data. b) How long was the incubation period. c) What caused the fever and how long did it last. 7: a) What is an antibiotic and how was the first antibiotic discovered. b) In hospitals, patients are treated for bacterial infection by doctors using antibiotics. Some of the bacterial strains become resistant to antibiotics like penicillin. How might this happen. 8: What is the difference between the following; a) An antiseptic and a disinfectant. b) An antibody and an antibiotic. c) A vaccine and vaccination. 9: Explain why you should: a) Never share a bath towel with someone. b) Always wash your hands before handling food. c) Always wash your hands after going to the toilet. d) Always refrigerate food and throw away after the ‘use by’ date. e) Always cook meat thoroughly. f) Never share needles and always practice safe sex using the barrier method e.g. condoms. Science Interactive LTD Copyright 2005 37 o C 2 39 o C 6 37 o C 16 38 o C 14 40 o C 10 39 o C 8 37 o C 40 o C 38 o C 37 o C Body temperature 18 12 4 0 Day

10: The movement of blood through the circulatory system of a mammal is described as a double circuit (a) Explain how the structure and the tissues of the heart maintains the double circulation blood pressure (b) Why is the muscle wall of the left ventricle thicker than that of the right (c) Explain the role of the bicuspid, tricuspid and semi-lunar valves. 11: Give a function for each tissue of the heart. 12: A high altitude there is less oxygen in the air. People who live at high altitude make more red blood cells to acquire sufficient oxygen from the air. The table shows an analysis of blood of 3 people. 13: (a) which individual lives at the highest and lowest altitude. Explain your answer. (b) Which person is suffering from non-sickle cell anaemia. (c) Which person will not clot properly when their blood vessels are cut. (d) Which person can deliver most oxygen (mm 3 /min) to the muscle cells. Internet: Go to google.co.uk and find about how platelets form scabs when the skin and its capillaries are cut. Find out how a high fat diet affects the cardiovascular system and what is a heart attack. Science Interactive LTD Copyright 2005 Pulmonary artery Pulmonary vein Left atrium R_____ A______ Part Smooth heart lining Takes blood to body A______ Right ventricle Receives blood from body Left ventricle Function Function Part 210,000 7,000 4,500,000 Person B 1000 200,000 Platelets (mm 3 ) 6,000 6,000 White blood cells (mm 3 ) 2,000,000 8,000,000 Red blood cells (mm 3 ) Person C Person A Measurement