1. Nutrition
   1. definitn
      1. process of taking in food & converting into living matter.
         1. Holozoic Nutrition(mode of feeding)
            1. animals feeding on complex organic matter(solid/liquid)
   2. consists of:
      1. Feeding/ingestion
         1. food intake
      2. Digestion
         1. breakg large food molecules into smaller m. for absorbtion into cells
      3. Absorption
         1. absorb digested food subst into body cells
      4. Assimilation
         1. some absorbed food subst converted into new protoplasm/ used to provide energy
2. Special organ system for nutritn
   1. Abdomen
      1. Gut
         1. (intestine)
         2. liver
         3. gall bladder
         4. pancreas
3. Mammalian Digestive System（妈妈脸）
   1. consists:
      1. Gut/ Alimentary Canal
         1. "tube extends frm mouth to anus
            1. most of its length coiled in abdomen / Abdominal Cavity
      2. Glands
         1. a cell/ tissue/ organ that secretes chemical substance
            1. eg
            2. Salivary Glands secrete saliva
   2. Mouth & Buccal Cavity
      1. food enters through:
         1. Buccal Cavity
            1. consists:
            2. Teeth
            3. breaks down large food pieces into smaller.
            4. increases surface area for enzymes to act on
            5. Salivary Glands
            6. secretes saliva into mouth
            7. flows into Buccal Cavity via tubes:
            8. Ducts
            9. Tongue
            10. mix food w saliva
            11. Taste Buds
            12. help identify & select suitable food
   3. Pharynx
      1. part of gut
         1. connects buccal cavity
            1. to:
            2. Oesophagus
            3. food passes thru
            4. muscular tube
            5. passes thru
            6. Thorax(chest)
            7. Diaphragm
            8. sheet of muscle separating thorax frm abdomen
            9. related to respiration
            10. 2 layers
            11. Longitudinal muscles
            12. (outside of gut)
            13. Circular muscles
            14. (inside of gut)
            15. P010509_23.43.JPG
            16. Peristalsis
            17. contractn & relaxatn of gut walls
            18. enables food to mix w digestive juices & move along w gut
            19. Circular muscles constrict LUMEN while Longitudinal muscles shorten LUMEN
            20. both muscles are: Antagonistic muscles
            21. means: one contracts another relax
            22. when:
            23. circular muslces contract Longi. relax
            24. thus, gut wall constricts, becomes narrow & long
            25. food is pushed FW
            26. Longi. contract Circu. relax
            27. Gut dilates, becomes wider & shorter
            28. widens lumen for food to enter
            29. P010509_23.57.JPG
            30. Larynx(voice box)
            31. has slit-like opening:
            32. Glottis
            33. Trachea (windpipe)
            34. leads to:
            35. Lungs
            36. air passes thru
      2. Food & Air passes thru
         1. but during Choking
            1. food enters trachea
            2. Epiglottis
            3. flap-like tissue
            4. prevents food going wrongway
            5. above Larynx
            6. P010509_22.20.JPG
            7. swallowing
            8. Larynx moves up & epiglottis moves down, so Larynx is covered by Epiglottis
            9. hence no food enter Trachea
   4. Stomach
      1. Distensible muscular bag*(stretchable/ expandable)
         1. Fully distended
            1. sated
      2. Walls
         1. has numerous pits
            1. leds to Gastric Glands
            2. secretes gastric juice
            3. into stomach cavity
            4. for digestn
      3. stores food for hrs
      4. Pyloric Sphincter
         1. ring of muscles where stomach links to small intestine
         2. contracts
            1. entrance of it closes
         3. relax
            1. entrance of it opens
            2. allowg food to pass into small intes.
   5. Small intestine
      1. (last organ for digestion)
         1. Duodenum
         2. Jejunum
         3. Ileum
      2. contain
         1. Glands
            1. secretes Digestive Enzymes
      3. wall of small intestine
         1. adapted to absorb
            1. digested food products
            2. water
   6. Liver
      1. largest gland in body
      2. dark red
      3. made of 5 lobes
         1. 3 Right
         2. 2 Left
      4. Blood Vessels
         1. Hepatic Portal Vein
         2. Hepatic Vein
         3. Hepatic Artery
      5. secretes
         1. Bile
            1. Alkaline greenish yellow liquid
            2. contains
            3. Bile Salts
            4. speed up digestn of FATS
            5. Bile Pigments
            6. gives bile colour
            7. are waste products
            8. removed w faeces
            9. no enzymes
            10. means no digestion
   7. Gall Bladder
      1. no digestn
      2. Bile is stored temporarily here
      3. greenish yellow bag attached to liver
      4. when contract
         1. Bile flows into Duodenum via bile duct
   8. Pancreas