Describe the digestion, absorption and assimilation of milk in humans.

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Milk contains proteins,lipids and carbohydrates. Digestion of milk starts in the stomach, the enzyme rennin;in the gastric juice coagulates milk(caisenogens to casein/protein/converts it to a solid form to stay longer in stomach for digestion. Enzyme pepsin converts milk protein to peptides/peptides/shorter polypeptide chains;acidic nedium/HCI is needed for action of pepsin.

In the duodenum any undigested milk protein is converted to peptides/peptides by the enzyme trypsin from pancreatic juice;lipids present in milk are emulsified by bile salts in the duodenum to increase surface area for digestion. The enzyme lipase converts lipid to fatty acids and glycerol; alkaline pH;needed for digestion is provided by bile salts and sodium bicarbonate in pancreatic juice.

In the ileum all digestion is completed by enzymes in intestinal juice/succus entericus;produced in ileum. All peptides/peptones are broken down to amino acids by enzyme peptidase /(various peptidases);any undigested lipids in duodenum is converted to fatty acids and glycerol by intestinal lipase; milk sugar lactose is converted to galactose and glucose by enzyme lactase.Absorption of digested products occur across the walls of ileum through villi; the monosaccharides galactose and glucose, and all amino acids diffuse into blood capillaries in villi;through the villi epithelial cells fatty acids and glycerol are reconverted to fat droplets in the lacteal and taken eventually to the heart and circulated in body.Sugars and amino acids are taken to the liver via hepatic portal vein.In the liver regulation of amount of sugars and amino acids take place;and correct amounts are circulated to body tissues.Glucose and galactose are used to provide energy through respiration; amino acids are used for growth/build up of new cells;and repair; excess,amino acids are delaminated in the liver(urea is formed)and the carbohydrate portion which is used for respiration or converted to glycogen or fat and stored;fats are reconverted to fatty acids and glycerol lipids are used as structural materials to make cell membranes,used to provide energy in respiration when need arises/less carbohydrates in the diet/extra energy needed;fats are mainly stored under skin or in adipose/fat storage cells around organs;stored fat under skin provides insulation against cold temperatures.

Milk contains vitamins A,B and D which are absorbed in the ileum and colon;vitamin A is used for synthesis of rhodopsin needed for night/dark vision ;and for healthy skin.Vitamin B1 is needed by respiratory enzymes (as a cofactor), B2 is needed for respiration (forms part of enzymes) B12 is needed for synthesis of red blood cells.
Vitamin D is needed for absorption of calcium and phosphorus; and in their assimilation to make bones and teeth;milk has iron and calcium; iron is needed to make haemoglobin in red blood cells;calcium is used to make bones;for blood clotting;when vessel is cut.

Belan answered the question on March 15, 2019 at 06:33

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Describe the digestion, absorption and assimilation of milk in humans.

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