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form 4 biology chap6 pt5

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form 4 biology chap6 pt5

  1. 1. YOU WILL ACHIEVE…. To i d e n t i f y t h e p ar t s o f t h e d i g e s t i ve s ys t e m i n vo l ve d i n t h e ab s o r p t i o n o f d i g e s t e d f o o d ; To e x p l ai n t h e ad ap t i ve c h ar ac t e r i s t i c o f t h e d i g e s t i ve s ys t e m r e l at e d t o ab s o r p t i o n ; To d r aw & l ab e l t h e s t r u c t u r e o f a vi l l u s ; To e x p l ai n t h e p r o c e s s o f ab s o r p t i o n i n t h e vi l l us ;
  2. 2. A b s o r p t io n o f D ig e s t e d F o o d in S m a ll In t e s t in e 2 p r o c e s s o c c u r wh i c h ar e d i g e s t i o n & ab s o r p t i o n Th e p r o c e s s o f d i g e s t i o n i s c o mp l e t e d i n t h e i l e u m t o p r o d u c e s i mp l e s u g ar s , ami n o ac i d s , g l yc e r o l & f at t y ac i d s . Th e p r o c e s s o f ab s o r p t i o n al s o o c c u r s i n t h e i l e u m t o ab s o r b t h e p r o d u c t s o f d i g e s t i o n i n t o t h e b l o o d c ap i l l ar i e s & t o b e u s e d b y t h e c e l l s i n t h e b o d y. Ab s o r b b y v i l l i ( s i ng ul ar : v i l l us ) i n t h e wal l s o f t h e s mal l i n t e s t i n e . Eac h vi l l u s c o n t ai n s a n e t wo r k o f b l o o d c ap i l l ar i e s & a l ymp h c ap i l l ar y i n t h e
  3. 3. A d a p t a t io n o f t h e s m a llin t e s t in e t o a id a b s o r p t io n
  4. 4. LEARNING OUTCOMES Explain the adaptive characteristic of thedigestive system related to absorption.
  5. 5.  I t i s l ong & coi l e d t o i n c r e as e t h e s u r f ac e ar e a f o r ab s o r p t i o n Th e l i n i n g o f t h e i n t e s t i n e i s g r e at l y f o l d e d t o i n c r e as e t h e s u r f ac e ar e a f o r ab s o r p t i o n Th e e p i t h e l i al c e l l s l i n i n g t h e vi l l u s i s ve r y t h i n t o
  6. 6.  Th e r e ar e man y vi l l u s & mi c r o vi l l u s t o i n c r e as e s u r f ac e ar e a f o r ab s o r p t i o n Eac h vi l l u s h as a n e t wo r k o f b l o o d c ap i l l ar i e s t o t r an s p o r t t h e d i ge s t e d f ood t h at h as b e e n ab s o r b e d Eac h vi l l u s al s o h as l ac t e al ( l ymp h ve s s e l ) t o t r an s p o r t g l yc e r o l & f at t y ac i d s .
  7. 7. S t r u c t u r e o f v illi
  8. 8. LEARNING OUTCOMESExplain the process ofabsorption in the villus.
  9. 9.  Blood capillaries at the villus absorb glucose (simple sugar), amino acids, minerals, vitamins B & C by simple diffusion through the epithelium of the villus These substances are carried by the hepatic portal vein to the liver & then distributed to the body cells by the circulatory system The products of fats digestion such as glycerol & fatty acids as well as vitamins A, D, E & K are absorbed into the lacteal of villus
  10. 10.  Across the thin epithelium into the lacteal. Once inside the lacteal, they recombine to form fat droplets. The fat droplets & vitamins ADEK in the lacteals are carried out of the ileum by a lymph vessel called thoracic duct. Ileum  thoracic duct  left shoulder vein (left subclavian vein)  bloodstream  body cells
  11. 11.  The absorptive surface area of the small intestine is roughly 250 square meters - the size of a tennis court!!!
  12. 12. A B S O R P T IO N OF WA TE R &M IN E R A L S IN C OLON
  13. 13.  Large intestine : – Caec um : t h e p ar t wh e r e t h e s mal l i n t e s t i n e j o i n s wi t h t h e l ar g e i n t e s t i n e – Col on : t h e l o n g e r p ar t o f t h e l ar g e i n t e s t i n e – Rec t um : t h e l as t p ar t o f t h e l ar g e i n t e s t i n e
  14. 14.  F l u i d mat e r i al f r o m i l e u m ( n o t ab s o r b e d )  c ae c u m  col on Col on abs or bs mu c h o f t h e wat er f r o m t h e i n d i g e s t i b l e f o o d r e s i d u e wh i c h b e c o me s mo r e s o l i d as i t p as s e s al o n g . Co l o n al s o abs or bs m ner al s i f r om t h e i nd i ge s t i b l e r e s i d u e
  15. 15. TRANSPORT OFNUTRIENTS BYCIRCULATORY SYSTEM
  16. 16. LEARNING OUTCOMESDescribe the transport ofnutrients by the circulatory system for assimilation.
  17. 17.  Glucose + amino acids + minerals + vits. B & C  blood capillaries of the villus  out of the small intestine  liver (by the hepatic portal vein)  the food molecules are transported away to all the cells in the body by the blood circulatory Glycerol + fatty acid + vits. A, D, E & K  the lacteal of the villus  transport out of the small intestine by the thoracic duct (lymph vessel)  lymphatic system  at the left shoulder, the thoracic duct joins the left subclavian vein  bloodstream
  18. 18. A S S IM IL A T IO N B Y B ODY C ELL Assimilation : the process where the products of digestion are absorbed & utilised in the body cells Used to synthesis complex molecules required for growth, reproduction or repair. (amino acids are used to synthesis protoplasm of cells) Excess absorbed food molecules are stored in the body
  19. 19.  Glucose = oxidised to produce energy in cell respiration, excess  glycogen Amino acid = to synthesis enzymes, antibody, plasma membrane & protoplasm, excess  urea  urine (deamination) Lipids = to build plasma membrane & cholesterol, excess  stored as adipose tissue (under the skin, abdomen & internal organs as kidneys, hearts) Minerals & vitamins = assimilated by the body cells
  20. 20.  Minerals (calcium & phosphorus)  build strong bone & teeth Iron  to synthesis haemoglobin in the RBC, excess  stored in liver Vitamins A & D also stored in the liver.
  21. 21. LEARNING OUTCOMES Explain the main function of the liver and describe the process of assimilation.
  22. 22. F U N C T IO N S O F T H E L IV E R Th e l ar g e s t g l an d i n t h e b o d y & c ar r i e s o u t man y me t ab o l i c p r o c e s s e s Car r i e s o u t as s i mi l at i o n & al s o ac t as a s t o r ag e o r g an Re c e i ve s t h e p r o d u c t s o f d i g e s t i o n d i s s o l ve d i n t h e b l o o d vi a t h e h e p at i c
  23. 23. M A IN F U N C T IO N S O F T H E L IV E R•Storage of nutrients•Processing the products of digestion•Detoxification•Breakdowns of lipids in storage to provideenergy•Production of bile•Removal of damaged red blood cells•Synthesis of vitamin A & blood clottingsubstances•Synthesis of plasma protein (fibrinogen,prothrombin).
  24. 24. REGULATION OF BLOOD GLUCOSE LEVELS Excess glucose  glycogen (present of hormone insulin)  stores in the liver. Lack of glucose; glycogen  glucose by hormone glucagons.
  25. 25. DEAMINATION Excess amino acids  liver  amino group is removed (-NH2)  ammonia (toxic)  urea  urine Remaining amino acids  carbohydrate or fat.
  26. 26. STORAGE FUNCTION Stores vitamins A & D and B12. Some minerals : irons, potassium, cobalt, zinc & copper.
  27. 27. DETOXIFICATION Bacteria  engulfed & destroyed by phagocytic cells in the liver. Toxin  chemically modified  non-toxic  eliminated. Cirrhosis  long time intake of large quantities of alcohol @ viral diseases (hepatitis)

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