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3rd 10 units 10 11 students

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Diet, nutritional requierements, chemicals, digestive system

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3rd 10 units 10 11 students

  1. 1. CALORY: 1 cal= 4,187 j. It’s not very used now. It expresses THE ENERGETIC POWER OF FOOD. It’s the amount of Caloric Energy necessary to increase in 1°C the temperature of 1 gram of What water is a calorie? KJ: derived unit of energy or work in the International System of Units, it’s the amount of E by completely oxidizing 180 gram of glucose
  2. 2.  We need food for 1) energy. 2) for growth provides the substances needed for making new cells/tissues  3) for replacement of worn and damaged tissues
  3. 3. CARBOHYDRATES PROTEINS LIPIDS Elements they contain C,H,O C,H,O,N,S C,H,O Smaller molecules of which they are made Glucose/simple sugar Amino acids (3) fatty acids and (1) glycerol Solubility in H2O Monosaccharides YES Polysaccharides NO YES NO Food that contains them Bread, cereals, deserts, potatoes, rice, pasta, jam, sweets, lettuce Meat, fish, chicken, egg white, milk, cheese, pork, peas, beans and cereals Butter, oils, fat meat, junk food, egg yolk
  4. 4. Why animals need them Easily available energy (16kj/g) Making CELLS,ANTIBODIES , ENZYMES; used for ENERGY if all the stores have run out (17kj/g) *Source of ENERGY (37kj) *LONG TERM storage of E in fat depots *insulation (adipose tissue) *part of cell membrane and membrane systems Things to remember ProteinsAminoaci ds bloodstream build up different proteins (cytoplasm/enzyme s) aminoacids not usedLiVERremo val of amino group (-NH2)  Glycogen Stored or OXIDIZED for E SUGAR GLUCOSE
  5. 5. Why do we need vitamins and minerals? Mineral Found in Why it is needed Deficiency disease IRON in RED meat, eggs, bread, spinach, lentils haemoglobin carries O2 round the body  when destroyed stored in the LIVER  needed in MUSCLES and ENZYME SYSTEM ANEMIA  lack of red blood cells less O2 CALCIUM milk, cheese not soluble in water=> not absorb needs vitamin D and bile salts *hardens bones and teeth/ *part of blood clotting(plasma)/ *needed for chemical changes in MUSCLES and transmission ofNERVE IMPULSES brittle bones and teeth IODINE SEA fish, shellfish and most vegetables part of the Thyroxine molecule hormone produced by Thyroid gland GOITRE sweeling of the neck and slow metabolism PHOSPHORUS Milk, cheese,meat and fish Needed for Calcium phosphate of the bone and DNA brittle bones and teeth
  6. 6. What are the vitamins? 1) organic substances quite unrelated to each other in structure 2) Characteristics: * not broken down for E *not built into the body structure *essential in small quantities *needed for chemical reactions associated with enzymes 3) They can be: WATER soluble (green leaves, fruits, grains) or FAT soluble (animal fat or vegetable oils)
  7. 7. Vitamin Found in Why it is needed Deficiency disease Notes A (RETINOL) FAT SOLUBLE A (CAROTENE) WATER SOLUBLE Butter, margarine,egg yolk, milk, liver Green vegetables and carrots *Keep the cells lining the respiratory system healthy *make pigment in the rod cells in the retina, needed for seeing in dim light *Keratomalacia (ulceration of the cornea), night blindness *infections of the cells lining the respiratory syst *stored in the LIVER Can’t be stored B 1-2-6-9-12 FOLIC ACID Water soluble Wholemeal bread, brown rice, yeast, liver Involved in chemical reactions FOLIC ACID very imp in pregnancybirth disease like spine bifida NERVOUS SYST BERI-BERI :diet based on polished rice causing muscular weakness and paralysis 10 or more vitamins B come all together C (ascorbic acid) WATER SOLUBLE Grapes, potatoes, citrics, brown rice Keeps tissues in good repair (connective tissues&blood vessels) Acts as catalyst in cell respiration SCURVY: causes pains in joints and muscles bleeding gums Only in fresh food, can’t be stored, daily intake is needed D (Calciferol) FAT SOLUBLE Butter, milk, egg yolk, cheese, liver, fish liver oil Helps Calcium and phosphate to be used for making bones Helps absorption of Calcium from intestine RICKETS (bones are soft and deformed) OSTEOMALACIA Can be made by the skin when sunlight shines on it K Green vegetables, made by a bacteria living in the intestine Plays a part in the blood-clotting process Unlikely to be lacking except in people whose intestinal bacteria have been reduced by antibiotics
  8. 8. Water functions
  9. 9.  In our cells, chemical reactions take place in water  Waste chemicals are diluted in water in order to be passed out of our bodies  Blood transport substances dissolved in water Why do we need water?
  10. 10. Can we digest fibre?? NOOOOOO To digest fibre, the enzyme cellulase must be present to break down cellulose, which compose the cell wall. In our digestive system, we can't synthesise this enzyme. Thus, we can't digest fibre What is the function of fibre? To keep the digestive system healthy and functioning properly. Fibre aids and speeds up the excretion of waste and toxins from the body, preventing constipation. It stimulates peristalsis and help retain water
  11. 11.  ENERGY REQUIREMENTS per day => 12000kj (=2800cal) For *keeping our internal body processes working *keeping our body temperature *meeting the needs of work and activities 8 hours asleep 2400 kj 8 hours awake (inactive) 3000 kj 8 hours physically active 6600 kj Balanced diet Total 12000 kj BASAL METABOLISM  2400 kj (574cal in 8 hours of sleep) maintains circulation/ breathing/body temperature/ brain function/chemical processes in liver and other organs
  12. 12. Special NEEDS PREGNANCY proteins, calcium, vitamin D, folic Acid LACTATION  proteins, vitamins, calcium GROWING CHILDREN  calcium, iron, vitamin D, vitamin A (disease resistance) MALNUTRITION insufficient, excessive or imbalanced comsuptiom of nutrients MARASMUS no food intake, E deficency KWASHIORKORpot belly/ no proteins
  13. 13. Digestion  Digestion is the breakdown of large food molecules into small food mollecules in the digestive system, so that they can be absorbed into the bloodstream and carried to every cell of the body.
  14. 14. Digestive system  Digestive truct Esophagus Stomach Small intestines Large intestines Rectum and anus  Glands Salivary glands Liver Gallbladder Pancreas
  15. 15. Path of Food Mouth--chewing Pharynx--conscious swallowing Esophagus--transport to stomach Stomach--mechanical and chemical breakdown Small Intestines-- chemical digestion and absorption Large Intestines-- resorb water, form feces Rectum---collect and expel feces
  16. 16. MOUTH Mechanical and chemical digestion start in the mouth. Saliva contains the enzyme amylase ( it breaks down starch into sugar). Saliva also contains mucus which lubricates the food and helps it pass down the oesophagus. Saliva lubricates and stick the small pieces togetherbolus
  17. 17. Chewing and swallowing SWALLOWING: Food passes from the MOUTH to the PHARYNX and into the ESOPHAGUS 1 The tongue presses UPWARDS and BACK against the roof of the mouth 2 The SOFT PALATE closes the NASAL CAVITY 3 The LARYNX cartilage is pulled upwards so that the glottis is under the back of the tongue 4 The GLOTTIS is partly closed 5 The EPIGLOTTIS shuts down to help prevent food from going down the WINDPIPE The beginning is VOLUNTARY, once food gets to the back of the mouth  REFLEX ACTION
  18. 18. Peristalsis The oesophagus has circular muscles in the wall. These muscles contract behind the bolus to push it along and the muscles in front of the food relax. This way food passes along the oesophagus to thestomach. This movement is known as peristalsis. http://www.passmyexams.co.uk/GCSE/biology/digestive_system.html
  19. 19. Enzymes in digestion. Enzymes are chemicals that break down large food molecules into small food molecules.
  20. 20. STOMACH FUNCTION –Mechanical and chemical breakdown of food Protein breakdown-pepsin secreted by epithelial lining ◦ Acidic conditions--for pepsin to work and to kill bacteria The gastric juices contain protease enzymes (PEPSIN) and hydrochloric acid
  21. 21. STOMACH Food+ GASTRIC JUICE= ◦ From esophagus (cardiac orifice or lower esophageal sphincter) ◦ To small intestine (pyloric sphincter) CHYME
  22. 22. SALIVA + Amylase Chewing Esophagus Stomach PERISTALSIS Gastric juices: Pepsin+ Hydrochloric acid Pancreatic juice (TRYPSIN+PANCREATIC AMYLASE+LIPASE)+ SODIUM HYDROGENCARBONATE Small Intestine- DUODENUM Bile Small Intestine- Illeum Absorption Liver Assimilation of produtcs EGESTION KIDNEYS LARGE INTESTINE Colon absorbs FATTY ACIDS, BILE SALTS; WATER
  23. 23. INTESTINES  Small Intestine  Large Intestines Absorption of nutrients Reabsorption of water Duodenum / Ileum Cecum, colon, rectum and anal canal. the ascending colon, the transverse colon, the descending colon, and the sigmoid colon.
  24. 24. Small Intestine: Modifications for absorption dense capillary network Digested food passes to the blood to be taken to the liver and then distributed round the body Microvilli: Increases surface area  the larger the surface, the faster the absorption thin epithelium increases contact, fluids can pass easily to reach the capillaries Length It gives plenty of time for digestion to be completed and for digested food to be absorbed
  25. 25. *They work in stages and different parts of the canal  e.g: starch  MALTOSE  GLUCOSE (SALIVA/PANCREAS) protein  PEPTIDE  Amino acid (AA) (STOMACH)  Fats  LIPASE  GLYCEROL+ FATTY ACIDS *TYPES: 1) CARBOHYDRASES  digest CH e.g  AMYLASE => MALTOSE  MALTASE => GLUCOSE 2) LIPASES  digest FATS into=> fatty acids and glycerol 3) PROTEASES  digest proteins into POLIPEPTIDES => Amino acid (AA) *
  26. 26. PROTEASES are produced in an inactive form + MUCUS * PEPSIN is produced as PEPSINOGEN and becomes PEPSIN when it encounters HYDROCHLORIC ACID * TRYPSIN is produced as TRYPINOGEN and becomes TRYPSIN when it encounters ENTEROKINASE (produced by duodenum lining) BRAIN nerve impulses GASTRIN  when food reaches the stomach, circulates in the blood to maintain the gastric secretion SECRETIN stimulates secretion of ENTEROKINASE and SODIUM HYDROCARBONATE
  27. 27. Interesting Facts about the Digestive System… •We eat about 500kg of food per year. •We produce 1.7 litres of saliva each day. •In the mouth, food is either cooled or warmed to a more suitable temperature. •The oesophagus is approximately 25cm long. •Muscles contract in waves to move the food down the esophageus. This means that food would get to a person's stomach, even if they were standing on their head. •An adults stomach can hold approximately 1.5 litres of material and produces about 2.5 litres of gastric juice everyday. •In an average person, it takes 8 seconds for food to travel down the food pipe, 3-5 hours in small intestine and 3-4 days in the large intestine. •The human body takes 6 hours to digest a high fat meal and takes 2 hours for a carbohydrate meal. •Every day 11.5 litres of digested food, liquids and digestive juices flow through the digestive system, but only 100mls is lost in faeces. •Most of us pass somewhere between 200 and 2,000 ml of gas per day. These emissions are composed of five gasses: nitrogen (N2), oxygen (O2), carbon dioxide (CO2), hydrogen (H2), and methane (CH4).
  28. 28. INGESTION DIGESTION ASSIMILATION ABSORPTION EGESTION D U O D E N U M I L E U M AMYLASE Salivary/pancreatic PEPSIN TRIPSIN BILE salts LIPASE MALTOSE PEPTIDES MALTOSE GLUCOSE AA
  29. 29. ILEUM ABSORPTION GLUCOSE and AA  Epithelial cells =>Capillaries =>VEINS =>HEPATIC PORTAL VEIN => LIVER => BLOOD CIRCULATION GLYCEROL+ FATTY ACIDS  LACTEALS => Lymphatic system => bloodstream HOW  water/alcohol => OSMOSIS Amino acids/ salts/sugars =>ACTIVE TRANSPORT FAT soluble VITAMINS =>ACTIVE TRANSPORT (+fat droplet) WATER soluble VITAMINS => DIFFUSION CALCIUM IONS => need VITAMIN D => ACTIVE TRANSPORT
  30. 30. ASSIMILATION : uptake and use of food STORAGE GLUCOSE  ENERGY from respiration *GLYCOGEN in LIVER (Short term storage) and MUSCLE *FAT  fat depots FATS  to form some cell structures (membranes) or as a source of ENERGY *LONG-TERM STORAGE  FAT DEPOTS ADIPOSE TISSUE (round kidneys/under skin) AMINO ACIDS  build up proteins forming tissues/enzymes *NOT STORED in the body DEAMINATED (-NH2)
  31. 31. redish-brown organ which lies beneath the diaphram and overlaps the stomach partially ALL THE BLOOD FROM THE BLOOD VESSELS OF THE ALIMENTARY CANAL PASSES THROUGH THE LIVER, ADJUSTING ITS COMPOSITION BEFORE JOINING GENERAL CIRCULATION Functions: 1) REGULATION OF BLOOD SUGAR: removes excess glucose and stores it as GLYCOGEN (normal level 80/150mg) or from GLYCOGEN to GLUCOSE maintaining HOMEOSTASIS (internal environment within narrow limits) and the composition of the BODY FLUIDS 2) PRODUCTION OF BILE  BILIRUBIN pigment from breakdown of haemoglobin . BILE contains bile salts (for digestion of fats) 3)STORAGE OF IRON 4)DEAMINATION  conversion of useless AA to glycogen removing the amino group (-NH2)Ammonia (poisonous) UREA excreted by the KIDNEYS 5) MANUFACTURE OF PLASMA PROTEINS 6) DETOXIFICATION  ALCOHOL/MEDICINES 7) STORAGE OF VITAMINS A AND D
  32. 32. PART OF CANAL JUICE SECRETED ENZYMES SUBSTANCE PRODUCT OTHER SUBSTANC ES IN THE JUICES FUNCTION OF THE OTHER SUBSTANCES MOUTH Saliva amylase starch maltose - - PHARYNX - - - - - - STOMACH Gastric juice Pepsin proteins Poly peptides Hydro chloric acid Gives acidity for the pepsin to work Kills bacteria DUODENUM *pancreatic juice Amylase Lipase trypsin Starch Fats Proteins and Polypeptides Maltose Fatty acids/ glycerol Sodium hydrogen carbonate Neutralises acidity of chyme Makes the environment alkaline * Bile (liver) Bile salts &pigments Emulsify fats Excretory product ILEUM - Maltase Sucrase Lactase Peptidase Lipase Maltose Sucrose Lactose Polypeptides Emulsify fats Glucose Glucose & Fructose Galactose& Glucose Aminoacids Fatty acids/ glycerol
  33. 33. Overview of the Digestive System 1 - the first part of the digestive system, where food enters the body. Chewing and salivary enzymes in the mouth are the beginning of the digestive process (breaking down the food). - glands located in the mouth that produce saliva. Saliva contains enzymes that break down carbohydrates (starch) into smaller molecules. - the long tube between the mouth and the stomach. It uses rhythmic muscle movements (called peristalsis) to force food from the throat into the stomach. - rhythmic muscle movements that force food in the esophagus from the throat into the stomach. Peristalsis is involuntary - you cannot control it. It is also what allows you to eat and drink while upside-down. - a large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile (which breaks down fats) and some blood proteins. - a sack-like, muscular organ that is attached to the esophagus. Both chemical and mechanical digestion takes place in the stomach. When food enters the stomach, it is churned in a bath of acids and enzymes. 2 6 1 3 4 5 Salivary glands / Stomach / Mouth / Esophageus / Peristalsis / Liver
  34. 34. Overview of the Digestive System 1 - the first part of the digestive system, where food enters the body. Chewing and salivary enzymes in the mouth are the beginning of the digestive process (breaking down the food). 2 - glands located in the mouth that produce saliva. Saliva contains enzymes that break down carbohydrates (starch) into smaller molecules. - the long tube between the mouth and the stomach. It uses rhythmic muscle movements (called peristalsis) to force food from the throat into the stomach. - rhythmic muscle movements that force food in the esophagus from the throat into the stomach. Peristalsis is involuntary - you cannot control it. It is also what allows you to eat and drink while upside-down. - a large organ located above and in front of the stomach. It filters toxins from the blood, and makes bile (which breaks down fats) and some blood proteins. - a sack-like, muscular organ that is attached to the esophagus. Both chemical and mechanical digestion takes place in the stomach. When food enters the stomach, it is churned in a bath of acids and enzymes. Salivary glands / Stomach / Mouth / Esophageus / Peristalsis / Liver 1 3 4 5 6 2 6 1 3 4 5
  35. 35. - food in the stomach that is partly digested and mixed with stomach acids. It goes on to the small intestine for further digestion. - a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical which is produced in the liver) into the small intestine. - a digestive chemical that is produced in the liver, stored in the gall bladder, and secreted into the small intestine. - an enzyme-producing gland located below the stomach and above the intestines. Enzymes from the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine. - the first part of the small intestine; it is C-shaped and runs from the stomach to the jejunum. Overview of the Digestive System 2 4 5 1 2 3 Pancreas / Duodenum / Chyme / Gall bladder / Bile
  36. 36. Overview of the Digestive System 2 - food in the stomach that is partly digested and mixed with stomach acids. It goes on to the small intestine for further digestion. 2 - a small, sac-like organ located by the duodenum. It stores and releases bile (a digestive chemical which is produced in the liver) into the small intestine. - a digestive chemical that is produced in the liver, stored in the gall bladder, and secreted into the small intestine. - an enzyme-producing gland located below the stomach and above the intestines. Enzymes from the pancreas help in the digestion of carbohydrates, fats and proteins in the small intestine. - the first part of the small intestine; it is C-shaped and runs from the stomach to the jejunum. 4 5 1 2 3 Pancreas / Duodenum / Chyme / Gall bladder / Bile 1 3 4 5
  37. 37. The Digestive System
  38. 38. Answers

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