TOPIC 53 Animal Nutrition 5.1 Diet 5.2 Human Alimentary Canal 5.3 Mechanical and Physical Digestion 5.4 Chemical Digestion 5.5 Absorption and Assimilation Use the following to check what you can do, ffick one of the columns for each criterial o Define balanced diet . List the different classes of food that make a balanced diet List the chemical elements which make up carbohydrates, fats and proteins . State the importance of protein, carbohydrates and fats in our diet State the importance of taking Vitamins C and D, minerals (calcium & iron) and fibre in our diet Give the sources for carbohydrates, proteins, fats, vitamins C and D and mineralsalts (iron and calcium) Explain the relation between diet and age, diet and sex and diet and activity of an individual . Deflne malnutrition . Explain constipation and the problems associated with this condition . Explain obesity and the health problems associated with this condition Name and state the function of the parts of the system that make up the human alimentary canal and the associated oroans . Define ingestion, digestion, absorption, assimilation and egestion To identify which part of the alimentary canat is involved in the process mentioned above tdentiff the different types of teeth and state their functions in relation to tooth structure r State the process and causes of tooth decay . State ways to prevent tooth decay LSC-201 l_C.S.Biology - Chp 5 Animal Nutrition Page I of2l
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TOPIC 53 Animal Nutrition
5.1 Diet
5.2 Human Alimentary Canal
5.3 Mechanical and Physical Digestion
5.4 Chemical Digestion
5.5 Absorption and Assimilation
Use the following to check what you can do,
ffick one of the columns for each criterial
o Define balanced diet
. List the different classes of food that make a balanced diet
List the chemical elements which make up carbohydrates, fats and
proteins
. State the importance of protein, carbohydrates and fats in our diet
State the importance of taking Vitamins C and D, minerals (calcium &
iron) and fibre in our diet
Give the sources for carbohydrates, proteins, fats, vitamins C and D
and mineralsalts (iron and calcium)
Explain the relation between diet and age, diet and sex and diet and
activity of an individual
. Deflne malnutrition
. Explain constipation and the problems associated with this condition
. Explain obesity and the health problems associated with this condition
Name and state the function of the parts of the system that make up thehuman alimentary canal and the associated oroans
. Define ingestion, digestion, absorption, assimilation and egestion
To identify which part of the alimentary canat is involved in the process
mentioned above
tdentiff the different types of teeth and state their functions in relation totooth structure
r State the process and causes of tooth decay
. State ways to prevent tooth decay
LSC-201 l_C.S.Biology - Chp 5 Animal Nutrition Page I of2l
Describe the proper care of teeth
. Describe chewing
. Describemechanicaldigestion
r Describe the process of peristalsis
. Definechemicaldigestion
r Distinguish chemical digestion and mechanical digestion
Describe the role of salivary and pancreatic amylase and maltase in fire
State the end-products f-or the digestion of starch
. Describe the functions of pepsin and lipase
. State the end products for digestion of proteins and fats
. State the optimum pH for these enzymes
. Describe how the digested food molecules are aGorbed in the bbol
o State the roles of liver in the digestion and assimilation of food
Explain what happens to excess glucose
Explain what happens to excess amino acids
. Explain wtrat happens to excess fats
Describe briefly how and in what form, exces@the bodv
LSC-201 I C.S,Biotogy - Chp S_Animal Nutrition Page2 of?l
5,2 HUMAN ALIMENTARY GANAL
* TIre food we eat goes through five different processes in our body:
(1) lngestion: taking food into the body (eating).
(2t Digestion:the breaking down of large complex food molecules into simple, soluble molecules.
(3) Absorption: digested food from the alimentary canal diffuses into the blood stream.
(4) Assimilation: the use of absorbed food to form new cells or part of cells.
(5) Egestion: passing out undigested food as faeces.
* 1yre atimentary canal is the canal (tube) along which food passes to be processed.
,/ Assimilation does not take place in the alimentary canal'
./ The human alimentary canalis about 900cm (9 m) long.
I The canal is able to fit into our bodies because it is folded into loops.
rt
Diagram below shows the human alimentary canal and the organs associated with it (shaded)
We must digest our food so that lt is small enough to pass through the thin walls of the ileum into the blood.
There are two types oi digestion:
(1) Physicaldigestion(2) Chemicaldigestion.
m
m
Physical Digestion
Digestion is the breaking down of large complex foods into smaller simpler food units.
Physical digestion breaks down food into smatler pieces. lt is sometimes calledmechanical digestion. This type of digestion does not chemically change the food.
Chewing
+ Example of physical digestion is chewing in our mouth with our teeth.
3E ffre functions of teeth are to cut, tear and grind food into smaller pieces.
ffi tt is important to chew our food because:
(a) it breaks the food up into smatler pieces that are easier to swallow.
(b) it makes digestion by enzymes easier. when food has been broken up into smaller pieces, thereis a larger surface area for the enzymes to act on.
(c) chewing allows the food to be mixed with the saliva.food to move easily along the alimentary canal.
+ There are fourdifferent types of teeth:
(1) incisor(2) canine
(3) premolar
(4) molar
Each type has a different shape, size and function.
Chemicaldigestion is a process by which complex food molecules are broken down intosimple soluble substances. Enzymes are used to produce these chemical changes.
Most of the food we ingest is insoluble and made up of molecules that are too large and complex to pass
through the wall of the small intestine (ileum) into the blood vessels.
Below shows digestion reduces complex food substances into simple units
-
digestion
o oooooo oo
glucose units
ooo
Bw
fE a".!
digcsrion nmamino acid units
Fnrt-Fats
%
cligestion
tfntf
farry acids and glycerol
f ln most animals, digestion is extracellular.
(Extracellular means that digestion takes ptace outside the body cells. ln most animals, digestion
takes place in ihe alimentary canal.)
* Example of extracellular digestions are:
salivarv amvlase
(b) Stomach: protein pepsn > polypeptide (peptones)
(c) Duodenum: fats bile (no enzyme) , emulsified fats
oancreatic amvlase
(d) lteum: maltose maltase , glucose
polypeptide (peptones) peptidase , amino acids
frts &'"e r fatty acids and glycerol
LSC-201 l-C.S.Biology - Chp 5-Animal Nutrition Page 17 of 27