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Chapter 6 nutrition

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  • 1. Chapter 6 : Nutrition
  • 2. Introduction • Nutrition - process by which organism obtain energy & nutrient from food • Need for growth, maintenance & repair of damaged tissues • Nutrients – substances required for nourishment of an organism • Types of nutrition is based on how an organism feed for their survival
  • 3. Types of nutrition Autotrophic nutrition Heterotropic nutrition Photosynthesis Chemosynthesis Holozoic nutrition Chemoautotrophs Photoautotrophs Saprophytism Parasitism Saprophytes Parasite
  • 4. Autotrophs • Autos : self trophos : feed • Organism which practise autotrophic nutrition • Synthesis complex organic compound (food) by their own • Using inorganic substances with the help of light/chemical energy • By photosynthesis or chemosynthesis
  • 5. Autotrophs Photosynthesis Photos : light - Green plants or photoautotroph - Produce organic molecules (food) from CO2 & H2O - Light as a source of energy Chemosynthesis Chemo : chemical - practise by certain type of bacteria or can be called as chemoautotroph - Produce organic compounds (food) without the help of light - Will oxides inorganic substances such as (hydrogen sulphide or ammonia) to obtain energy
  • 6. Heterotrophs • Heteros : other • Cannot synthesis their own nutrition • Organism which practise heterotrophic nutrition • Obtains energy through the intake & digestion of organic substances (plant & animal tissues) • May practise i-holozoic nutrition ii-saprophytism iii-parasitism
  • 7. i. Holozoic nutrition • Holo : like zoon : animal • Feed by ingesting solid organic matter & digest then absorbed it • Eg: human , all animal & carnivorous plant (capturing & ingesting small insects)
  • 8. Carnivorous Plants : Venus Flytrap Carnivorous Plants : Pitcher plant
  • 9. ii. Saprophytism • The organism are called as saprophytes, feed on dead & decaying organic matter • Such as bacteria & fungi • Digest food externally b4 absorb nutrient
  • 10. iii. Parasitism • Close association between 2 organism • Parasite – obtains nutrient (readily digested food) by living on or in the body of other living organism, host • Eg : fleas & lice, bacteria, fungi, worms (human alimentary canal) A cluster of nematodes, the  roundworm of dogs, Toxocara canis
  • 11. Match the following with correct answer • Feed on dead & decaying organic matter • Feed by ingesting solid organic matter & digest then absorbed it • Obtains nutrient by living on or in the body of host • Obtains energy through the intake & digestion of organic substances (plant & animal tissues) • Hetetrophs • Holozoic nutrition • Saprophytism • Parasitism
  • 12. The Importance of A Balanced Diet Balanced diet : Diet that has all the nutrients in the right amount. Why it is important: Obtained enough energy Maintain a healthy body Prevent infection of disease Quantity of nutrients depends on Age Condition of Health Type of Work Sex Physicals activities Environment Body Size Climate
  • 13. Balanced diet is a utmost importance to health • The necessity for a balanced diet in food consumed : 1- Provides energy for all biochemical reaction needed for living. Mammals & birds  need energy  to maintain body temperature 2- Provides the material needed to build cells & tissues for the growth process 3-To replace damaged & dead cells * The food in a balanced diet should contain the major nutrients includes carbohydrates, proteins, lipid, mineral salts, vitamins, roughage (dietary fibre) & water (7 classes of food) * These nutrients must be taken in the correct proprotions to meet the daily requirements of the body
  • 14. Daily energy requirement • Energy is needed to sustain vital functions – heartbeat, breathing & maintaining body temperature • It is generated by the oxidation of molecules obtain from food during cellular respiration • Energy content of food – determined by – burning a known mass of the food in the presence of oxygen in a bomb calorimeter • Energy value – the amount of heat generated from the combustion of 1 gram of food • Unit – joule per gram (J gˉ¹) • 4.2 joules of energy are needed to raise the temperature of 1 g of water by 1°C
  • 15. • 3 main energy-providing organic molecules are lipids, carbohydrates & proteins • 1 g of lipid – 37.6 kJ of energy (twice than protein & carbohydrate – almost 18.8 kJ) • Energy values of proteins = 22.2 kJ gˉ carbohydrates = 16.7 kJ gˉ¹
  • 16. Nutrient content in food • Carbohydrates  i. starch ( rice, flour, potatoes & cereals)  ii. sugar (sugar cane – main sources) • Proteins  meat, fish, egg, milk, cereals • Lipid  animals fat, butter, margarine, egg yolk • Others are vitamins, mineral, roughage, water
  • 17. Vitamins • Non-protein organic compounds cannot be synthesized by our body • Needed in small quantity • Cannot be digested & release no energy • Essential for the maintenance of good health & efficient metabolism • Defficiency in specific vitamins- lead to specific disease • 2 groups : i. Fat-soluble vitamins ii. Water-soluble vitamins
  • 18. 2 groups of vitamins Fat-soluble vitamins - Can be stored in body fat - Eg : Vit A, D, E, K Water-soluble vitamins - Can’t be stored in body - Have to be supplied in daily diet constantly - Eg : Vit B & C - Vit B complex – coenzyme ; work together with enzyme Vitamin E Vitamin D Vitamin K Vitamin A Vitamin B Vitamin A
  • 19. Sources of Vitamins, their functions and Deficiency effects Vitamins Source Function Deficiency effects A Egg, milk, cod liver oil, cheese, liver, papaya - Good vision - Healthy skin - Night blindness - Dry scaly skin B Egg, milk,liver, yeast and cereal - Preserves the nervous system - Beriberi - Pellagra - Insomnia C Fruits, tomato, green vegetable - Healthy skin - Absorption of iron - Anemia - Unhealthy skin - Scurvy D Egg, margarine, fish oil, milk, cheese - Absorption of calcium and phosphorus - Strong teeth and bones - Rickets - Tooth decay E Milk, egg, palm oil, green vegetable, cereal - Functions of reproductive system - Sterility K Liver, tomato, green vegetabe, spinach - Blood clothing - Difficulty in blood clothing
  • 20. Minerals • Simple organic nutrient obtained through the diet (food or drinks) • Required in small quantities in the ionic form by the body • Do not provide energy • Vital for the maintenance of good health • Babies require more calcium & phosphorus compared to adults for building strong bones and teeth • Adolescent girls require more iron than adolescent boys
  • 21. Mineral element Source Function Deficiency effect Calcium Egg yolk, milk, cheese, cereal, green vegetable - Strong bones and teeth - Blood clothing - Rickets - Osteoporosis - Tooth decay Iron Egg yolk, meat, liver, spinach - Component of the hemoglobin. - Anemia - Tiredness Phosphor us Egg, milk, fish, green vegetable - Strong teeth and bones - Rickets - Muscles cramps - Tooth decay
  • 22. Macrominerals Microminerals - Required in large quantities - > than 100 mg per day - Eg : Magnesium, potassium, calcium, phosphorus, chlorine, sodium, sulphur Phosphorus structural comp of Calcium bones & teeth Sodium nerve function & osmotic Potassium balance between body cell Chlorine - interstitial fliud - Required in trace amounts - < than 20 mg per day - have very specific functions - Eg : ferum, iodine, zinc, boron, copper molybdenum Ferum production of haemoglobin Iodine in thyroxine hormone
  • 23. Roughage or dietary fibre • Dietary fibre – indigestible part of plant food consists of mainly cellulose • Recommended – 25  50g • Eg : in vegetables, nuts, wholemeal grains, fruits • Passes out of the alimentary canal in the faeces without being absorbed or assimilated • Has high holding capacity & provides bulk to the intestinal content (in large intestine) • Deficiency - constipation
  • 24. Water • 70% of body is water • Main participant in biochemical reactions • Requires 2 to 2.5 litres of water daily • Loss from body by perspiration – skin, evaporation – lungs (breathing), excretion – kidney (urine or faeces) • Failure to replace the water lost - dehydration Food Drinks Sweat Urine Breath FaecesMade in body Water gained total = 2600 cm³ Water lost total = 2600 cm³ Daily water balance
  • 25. Functions: Help in the transportation To soften food To dissolve waste products To control the concentration To control body temperature To give shape to the body
  • 26. Selection of appropriates balanced diet Food guide pyramid
  • 27. Malnutrition • Unbalanced diet in which certain nutrients are lacking, in excess, or in wrong proportions • Protein deficiency - i. Kwashiorkor ; does not receive sufficient protein in diet – distended stomach, very thin, suffers from diarrhoea, thin hair, a swelling of the body due to retention of fliud in tissues, flaky skin & stunted growth - ii. Marasmus ; general wasting of body = protein deficiency + lack of energy-providing nutrients, very thin & wrinkled skin, usually occurs in children aged between 9 to 12
  • 28. Kwashiorkor Marasmus
  • 29. • Vitamin deficiency : - Vitamin C deficiency ; Scurvy ; swollen, bleeding gums & tooth loss - Effects of overdoses of vitamins Vitamin Effects C Gastrointestinal upset A Hair loss, vomiting, bone ache, joint pain, liver & bone pain E Kidney damage D Too much calcium in the blood –interferes with the functions of muscles & heart tissues K Liver damage &anemia B6 Numb feet & poor cordination B3 (niacin) Flushed face & hands Liver damage
  • 30. • Mineral deficiency : - Shortage of ferum ; anemia - Limited supply of Vit D, calcium & phosphorus ; rickets - Lacking in calcium ; osteoporosis – bones becomes porous & break easily
  • 31. Excessive intake of : i) carbohydrates & lipids – obesity  cardiovascular disease / diabetis melitus / cancer ii) sugar - diabetis melitus iii) vitamins A – hair lose, bone & joint paint, loss of appetite, liver damage iv) vitamin D – overload of calcium in blood & calcification of soft tissues v) sodium – high blood pressure , heart disease, stroke & (kidney stones) kidney failure vi) Protein – gout = uric acid forms crystal in the soft tissues of the joints.
  • 32. Food Digestion • Digestion – the process that breaks down complex food substances to simpler, soluble molecules small enough to absorb • Substances required by cells to carry out metabolic processes are : = glucose (starch) to generate energy = amino acids (protein) to synthesise new proteins = glycerol & fatty acids (lipids) to form plasma membrane
  • 33. Digestion of carbohydrates, proteins & lipids Take place in the alimentary canal : * A long, muscular tube extend from the mouth to the anus * Divided into specific regions for different digestive processes take place * Receive digestive juices (from accessory glands) * Food is broken down in stages till dissolved & absorbed * Indigestible residue expelled through the anus Digestion breaks down : A- starch into glucose B-proteins into amino acid C-lipids into glycerol & fatty acid
  • 34. Digestion • Involves physical & chemical processes i- Physical digestion : = breaking up of large pieces of food into smaller pieces by mechanical process = starts in mouth  slicing & chewing action of teeth = in stomach  curning action by the contraction of muscles in the stomach wall = increases the surface area of the food for chemical digestion
  • 35. ii- Chemical digestion : = digestive enzymes break down complex food molecules into smaller molecules which enter the bloodstream to transported to whole body = involves enzymatic hydrolysis
  • 36. 2. Salivary gland 1. Epiglotis 3. Oesophagus 6. Gall blader 7. Pancreas 4. Liver 8. Large intestine 5. Stomach 9. Small intestine 10. Rectum
  • 37. The components & functions of the human digestive system • Teeth – cut, tear & grind food • Tongue – helps swallow food • Salivary glands – release enzymes to break down carbohydrates • Epiglottis – prevents food from entering trachea • Oesophagus – tube connecting mouth to stomach • Stomach – i. mixes food with more enzymes to break down proteins ii. Hydrochloric acid kills bacteria • Small intestine – food substances absorbed into the bloodstream • Large intestine – reabsorption of excess water into the bloodstream • Liver – i. removes toxins from bloodstream ii. regulates food substances iii. converts excess amino acids to urea iv. Produces bile • Gall bladder – stores bile which neutralises stomach acid • Pancreas – secretes enzyme to break down carbohydrate, proteins & fats • Rectum – stores faeces • Anus – removal of faeces
  • 38. Digestion in the mouth • Digestion start here • Chewing action breaks the food into smaller pieces – exposes > surface area for enzyme’s reaction • Food in mouth will trigger salivary glands (3 pairs) – secretes saliva – contains salivary amylase • Tongue – ensure food mixed well with saliva • Salivary amylase – hydrolyse starch into maltose • Thoroughly chewed food rolled into a mass called bolus – preparation for swallowing • Then, bolus enter the throat  pharynx (junction of alimentary canal & passage of air flows into the lungs)  oesophagus • Epiglottis – a cartilage flap – will closed temporarily the airway to prevent food from entering the trachea Parotid gland Sublingual gland Submaxillary gland
  • 39. • Mucus lubricates the movement of the bolus along oesophagus by peristalsis (series of wave-like muscular contraction along the oesophageal wall) • The peristalsis action of the eosophagus wall squeezes the bolus down • Bolus enter the stomach when the cardiac sphincter relaxes Salive 3 salivary glands -Sublingual gland -Parotid gland -Submaxillary gland Food Starch Mouth Site of digestion Digestive juices Digestive enzymes Salivary amylase Enzymatic action Starch maltose + water Salivary amylase pH 6.5-7.5
  • 40. Digestion in the stomach • Stomach – thick wall, sausage-shaped organ, muscular sac with a highly folded inner wall. • Epithelial lining contains gastric glands  secretes gastric juice • Foods stay here for a few hours. It is thoroughly curned & mixed with gastric juice by the peristaltic contraction of the stomach wall • Gastric juice contains : i. Hydrochloric acid – a) creates the acidic condition (pH 1.5 - 2.0) for the optimal reaction of enzyme b) stops the activity of salivary amylase c) Helps to kill bacteria in food ii. Enzymes - a) Pepsin : proteins to polypeptides b) Rennin : caseinogen to casein • Then, contents of stomach become a semi-fluid called chyme • Chyme enters the duodenum when the pyloric sphincter relax
  • 41. Secretion of gastric juice in the stomach
  • 42. Food Protein Stomach Site of digestion Digestive juices Digestive enzymes -Pepsin -Rennin Enzymatic action Proteins Polypeptides + water pepsin pH Around 2.0 Gastric juice contains hydrochloric acid & enzymes Caseinogen casein + water rennin
  • 43. • Small intestine = duodenum + jejunum + ileum • Duodenum – 1st part ; receive chyme (stomach) & secretion (gall bladder & pancreas) • The digestion of starch, protein & lipid takes place here i) Pancreatic amylase : starch maltose ii)Trypsin : polypeptides peptides iii) Lipase : lipids  fatty acid & glycerol Digestion in the small intestine Starch + water maltose Pancreatic amylase Polypeptides + water peptides Trypsin Lipid droplet + water peptides Lipase
  • 44. Bile - Alkaline greenish-yellow liquid - Stored in gall bladder - Contains no digestive enzyme - Creates alkaline environment - Reduce the acidity of chyme - Emulsify lipids by changing lipids into tiny droplets Pancreatic juice - Contains enzymes pancreatic amylase, trypsin & lipase - Optimum pH required is between 7.1 & 8.2 LIVER PANCREAS secretes Duodenum
  • 45. • Ileum - The wall secretes intestinal juice Intestinal juice i) contains digestive enzymes for digestion of peptides & disaccharides ii) Require an alkaline medium for optimum reaction * End of digestion process: -i- all carbohydrates digested into monosaccharides (glucose, fructose galactose) -ii- proteins digested into amino acids -iii- lipids digested into fatty acid & glycerol -iv- vitamins & mineral (small & soluble – no need to digest) -v- Dietary fibre – not digested
  • 46. Protein digestion Peptides are digested by erepsin (a peptidase) into amino acids Peptides + water amino acids erepsin Carbohydrates digestion Maltose is digested by maltase into glucose The digestion of sucrose & lactose Lactose + water glucose + galactose lactase Sucrose + water glucose + fructose sucrase Maltose + water glucose maltase
  • 47. 1) Mouth   Here in the buccal cavity (mouth) the food is masticated (chewed). The buccal and naval cavity also warm up the air so that it does not interfere with enzyme production. The saliva, which contains Carbohydrase enzymes, changes starch into maltose.  
  • 48. 2) Oesophagus Next the food travels through the oesophagus or gullet which links the mouth and stomach together. These contract and push food along the gut, this is called peristalsis.
  • 49. 3) Liver The liver breaks up (emulsifies) fats by storing bile (the bile actually comes from the gall bladder). It is also alkaline which is good for the enzymes by giving them a good pH for them in the small intestine.
  • 50. 4) Stomach The food then enters your stomach. In your stomach starch, fat and protein are digested by enzymes. Hydrochloric acid is present to kill and neutralise bacteria which gives a low pH for the enzymes to work. Enzymes work perfectly at human body temperature at ice temperature, enzymes become deactivated but above body temperature they become denatured.    
  • 51. Pancreas The pancreas’s job is to produce three types of enzymes in pancreatic juices: Protease enzymes to digest proteins. Lipase enzymes to digest lipids e.g.. Fats. Carbohydrase enzymes to digest carbohydrates.
  • 52. The small intestine/ileum produces more enzymes to break up more proteins, fats and carbohydrates. It also absorbs the nutrients through the gut wall and into the blood stream through these ingenious cells, the villi which line the small intestine which are specially designed to absorb food efficiently. This process is a form of diffusion. Diffusion is the process of which a substance, commonly gas, transfers from a state of high concentration to low concentration to create balance. Small Intestine
  • 53. Large Intestine (Colon) The large intestine absorbs water and indigestible foods are stored here.
  • 54. Rectum Cellulose is often contained in foods. This cannot be digested so it must be egested. It is stored as fasces. Finally it comes of of the anus.
  • 55. Site of digestion Gland/organ Digestive juice Enzymes pH Food class Mouth Salivary glands saliva Salivary amylase 6.3- 6.8 Carbohydrates: Starch  maltose Stomach Gastric gland Gastric juice Pepsin Rennin 1.5 1.5 Proteins: Protein  polypeptides Caseinogen  casein Duodenum Liver Pancreas Bile, bile salts Pancreatic juice None Pancreatic amylase Trypsin Lipase 7.6- 8.6 7.1- 8.2 7.1- 8.2 7.1- 8.2 Emulsification of lipids Carbohydrates: Starch  maltose Proteins: Polypeptides peptides Lipids: Lipid droplets  fatty acids + glycerol Ileum Intestinal gland Intestinal juice Maltase Lactase Sucrase Erepsin 7.6 7.6 7.6 7.6 7.6 Disaccharides: Maltose  glu + glu Lactose  glu + galac Sucrose  glu + fruc Proteins: Peptides  amino acids
  • 56. Digestive system in ruminants
  • 57. Digestive system in rodents