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2013-04-28 08:52:58
nutrition biology

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  1. What is nutrition
    Nutrition is the way and organism obtains and uses its food
  2. What is autotrophic
    A type of nutrition where an organism makes its own food
  3. What is heterotrophic
    A type of nutrition where an organism cannot make its own food
  4. What is a parasite
    An organism that lives on a living organism ex. Flea
  5. What is a saprophyte
    An organism that lives on a non living organism ex. Fungi
  6. What is digestion
    The physical and chemical breakdown of good into soluble particles small enough to pass into body cells
  7. Need for a digestive system
    Food can be digested in a single location and individual cells to not have to contain a full range of digestive enzymes
  8. Stages of human nutrition
    1. Indigestion, food taken into alimentary canal

    2. Digestion, food broken down into smaller pieces

    3. Absorption, the movement of digested good from the alimentary canal into the blood stream

    4. Egestion, removal of unabsorbed material as farces
  9. What is peristalsis
    Peristalsis is the rhythmic contraction and relaxation in the walls of the alimentary canal causing the food to move along the canal
  10. Human teeth and functions
    Incisors - cutting

    Canines - tearing

    Premolars + molars - cutting grinding
  11. What is saliva made of
    • Water
    • Salts
    • Amylase
    • Lysozyme
  12. What is chyme
    Food and gastric juice, made in stomach
  13. What does gastric juice contain
    • Pepsinogen
    • HCl
    • Mucus
  14. Functions of gastric juice
    Pepsinogen: Converts to pepsin by HCl. Digests protein to peptides

    HCl: kills bacteria, activates pepsinogen

    Mucus: lines and protects stomach wall
  15. Protection from self digestion
    Mucus lines stomach, is alkaline and reduced acidity near stomach wall

    Pepsin is released in inactive form. Does not come into contact with stomach rolls.
  16. Sphincter muscles, and importance
    Cardiac sphincter muscle: closes entry from oesophagus to stomach

    Pyloric sphincter muscle: contracts to close entry to duodenum from stomach

    Importance: to prevent self digestion from stomach acids
  17. Function of small intestine
    Digestion and absorption
  18. 3 parts of small intestine
    • Duodenum
    • Jejunum
    • Ileum
  19. Function of duodenum
    Most digestion
  20. Functions of jejunum and ileum
    Absorb nutrients
  21. Adaptions for absorption
    1. Long tube, gives time for absorption

    2. Villi, infoldings increase surface area for absorption of food
  22. Parts of villus
    Lacteal and blood vessel

    Lacteal: absorbs fatty acids and glycerol

    Blood vessels: all other digested food glucose, amino acids, vitamins and minerals
  23. Parts of large intestine
    • Colon
    • Caecum
    • Appendix
    • Rectum
    • Anus
  24. Functions of colon
    • 1. Reabsorb water
    • 2. Produce B group vitamins*
    • 3. Digest cellulose*

    • *Symbiotic bacteria
    • Human benefit: B
    • Bacteria benefit: nutrition
  25. What are symbiotic bacteria
    Bacteria that lies in close contact with another organism where at least one organism benefits
  26. Function of caecum and appendix
    Function unknown
  27. Function of rectum
    Stores faeces
  28. Role of liver
    Produces bile
  29. Where is bile stored
    Gall bladder
  30. Bile consists of
    • Water
    • Bile salts
    • Bile pigments
  31. Functions of bile
    Emulsifies fat: increases surface area of fat droplets

    Neutralises: acidic chyme from stomach
  32. What does fibre so
    Fibre stimulates peristalsis in the colon

    • Prevents constipation
    • Occurs when material passes through colon too slow, leads to too much water reabsorbed
  33. Three enzymes in digestion a
    • Amylase
    • Pepsin
    • Lipase
  34. Salivary amylase

    Role, production site, where acts, pH, product
    • R: digest starch
    • P: salivary glands
    • W: mouth
    • pH: 8
    • P: maltose
  35. Pepsin

    Role, production site, where acts, pH, product
    • R: digest protein
    • P: gastric glands
    • W: stomach
    • pH: 2
    • P: peptides
  36. Lipase

    Role, production site, where acts, pH, product
    • R: digest fat
    • P: pancreas
    • W: duodenum
    • pH: 8
    • P: fatty acids+glucerol
  37. Absorption of nutrients
    Fatty acids and glycerol are absorbed from lacteal (small intestine) into the lymphatic system for transport to liver

    Glucose, amino acids, vitamins and minerals pass into the blood capillaries

    Hepatic portal vein brings these nutrients directly to liver
  38. What is a portal vein
    A vein that starts with a capillary becomes a vein and ends in a capillary
  39. Blood transport from intestine to liver
    1. Hepatic portal vein connects the small intestine to the liver, transporting glucose, amino acids, minerals and vitamins

    2. The hepatic vein transports nutrients and waste urea from liver to heart

    3. From the heart nutrients are transported away through aorta to body cells dissolved in plasma

    4. From the heart waste is transported away from the heart to the kidney through the aorta
  40. Functions of liver
    • 1. Makes bile
    • 2. Stores glycogen
    • 3. Breaks down vitamins
    • 4. Stores vitamins A, D, K (fat soluble)
    • 5. Make plasma proteins
    • 6. Makes urea from excess protein
    • 7. Produces heat

    • Bile gets too violent please use heat
  41. What is a balanced diet
    Taking in the correct amounts of all the essential nutrients in the diet
  42. How to get a balanced diet
    • Eat a variety of foods
    • Eat each food type in moderatoon
  43. Amount of food required depends in
    AGE (young more than old)

    GENDER (males more than females)

    ACTIVITY (active more than inactive)
  44. What is the food pyramid
    The daily food portion types an a average adult should eat
  45. Importance of water
    • Provides a medium for transport
    • Provides a medium for reactions to occur