explain the process of nutrition in human body and also in amoeba ? Explain fully if u don't know then don't reply ......
Answers
1. Ingestion, for which may be substituted more or less satisfactorily, rectal injection, inunction of fats, subcutaneous injection of salts, dextrose, etc., in solution, as well as gav-age, or feeding through a fistula;
2. Digestion, which does not apply to inorganic matters nor to organic foods already in the state suitable for absorption. Digestion is commonly divided into mechanic, including the comminution and softening of food, and chemic;
3. Absorption, through animal membrane, into the blood or lymph vessels;
4. Assimilation, which literally implies that the food is rendered like the body itself, and which, therefore, refers strictly only to the utilization of certain foods to repair or form tissue; the term is, however, usually extended to indicate the final utilization of any organic, or even inorganic, substance. Following assimilation, after a shorter or longer period, there is 5. Catabolism, which, like digestion, applies only to certain organic substances and which usually occurs in successive steps, often involving several organs:
6. Elimination of ultimate waste products, by the skin, lungs, kidneys and, to some extent, through the liver directly or even through the alimentary mucous membrane, independently of the liver. Substances which escape absorption in the alimentary canal are wasted rather than waste products.
IN AMOEBA
Nutrition in amoeba is holozoic. Thus, solid food particles are ingested which are then acted upon by enzymes and digested. It is an omnivore, feeding on both plants and animals. Its diet includes bacteria, microscopic plants like the diatoms, minute algae, microscopic animals like other protozoa, nematodes and even dead organic matter.
Since it is a unicellular organism, amoeba does not have any specialised structure or organ for the process of nutrition. It takes place through the general body surface with the help of pseudopodia.
Your answer :
Nutrition in amoeba
◇Amoeba is a unicellular , omnivore organism that does not possess specialised organ for the process of nutrition .
◇The mode of nutrition in Amoeba is HOLOZOIC and takes place with the highest elp of pseudopodia ( finger like structure ) .
◇It engulfs food when it comes in contact with its cell surface by ingestion .
◇Pseudopodia fuses over food particle to form food vacuole .
◇Digestion in Ameoba is INTRACELLULAR in nature. Inside the food vacuole, complex food breaks into small soluble molecules , This process is called ABSORPTION .
◇The absorbed food is further ASSIMILATED by Amoeba to derive energy for growth.
◇ The undigested food material is removed by the cell membrane, which ruptures suddenly at any place and eliminates out the undigested food.
◇The process of throwing out undigested food is called EGESTION.
NUTRITION IN HUMAN BEINGS
1. Nutrition in human beings takes place through parts like mouth, stomach, small intestine, large intestine, anus
2. The process of nutrition takes place through an alimentary canal which is a long tube extending from the mouth to the anus.
3. Complex foods should be converted to smaller ones by crushing the food with teeth and by the enzyme salivary amylase of saliva secreted by salivary glands.
4. Salivary amylase breaks down starch which is a complex molecule into sugar.
5. As the canal lining is soft so food is made wet to make the passage smooth.
6. The alimentary canal has different parts and the food should be moved in a regulated manner along the digestive tube so the food is processed properly in each part.
7. The canal has muscles that contract rhythmically to push the food forward and this movement of food is called peristaltic movement which occurs all along the gut.
8. The food is taken to the stomach through the food pipe or oesophagus from mouth.
9. The muscular wall of stomach mixes the food with more digestive juices secreted by the gastric glands present in the wall of the stomach.
10. Gastric gland releases hydrochloric acid, a protein digesting enzyme called as pepsin, mucus.
11. Enzyme pepsin acts on the food and hydrochloric acid facilitates the action of pepsin.
12. Mucus protects the inner lining of the stomach from the action of acid under normal conditions.
13. From stomach acidic food enters small intestine, the longest part of alimentary canal and this is regulated by sphincter muscle.
14. Complete digestion of carbohydrates, protein and fats take place in the small intestine by the secretions of liver and pancreas.
Bile secreted by liver makes the acidic food alkaline and acts on large globules of fat into smaller globules so that the enzymes can act on easily.
15. The process of breakdown of large fats globules into small globules which increases the efficiency of the pancreatic enzymes is called
Pancreas secrete pancreatic juice which contains enzyme trypsin to break for digesting proteins, lipase for digesting emulsified fats.
16. The walls of the small intestine contain glands secreting intestinal juice which converts finally complex carbohydrates into glucose, proteins to amino acids and fats into fatty acids and glycerol.
17. The inner wall of small intestine has finger like projections called villi which are richly supplied with blood vessels and these take absorbed food to all the cells of the body.
18. The unabsorbed food is sent to the large intestine where more villi absorb water from this undigested material and the rest of the material is excreted from the body by anus.
19. The excretion of waste materials by anus is regulated by the anal sphincters.
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