Functions Of Lipids

Functions Of Lipids

Question 1. Functions of lipids.
Answer.

Functions Of Lipids

• Lipids are constituents of membrane structure
• Lipids regulate membrane permeability
• Lipids are a source of fat soluble vitamins (A, D, E and K)
• Lipids take part in regulation of cell metabolism
• Lipids are an important source of energy (9.5 C/gm)
• Lipids can be stored in the body in unlimited amounts
• Lipids exert an insulating effect in the body
• Lipids around internal organs like kidney may provide padding and protect the organ
• Lipids are essential for proper functioning of the nervous system
• Essential fatty acids (PUFA’s) are required to be taken in the diet for normal health and growth

Functions of Lipids in the Body

Question 2. Digestion and absorption of lipids.
Answer.

Digestion of lipids:

Digestion In The Mouth

• The enzyme lingual lipase is secreted from the dorsal surface of the tongue (Ebners gland).
• It acts at a pH of 4 to 4.5.
• It breaks down TG to fatty acid and glycerol

Importance of Lipids for Energy Storage and Hormone Production

Digestion In The Stomach

• The enzyme gastric lipase acts at a pH of 7 to 8.
• It requires calcium ion for its activity.
• Activity of gastric lipase is seen when the intestinal contents are regurgitated into the stomach.
• Fats delay the rate of emptying of the stomach and thus have high satiety value.

Functions of Lipids: Energy Source, Protection, and Structure

Digestion In The Small Intestine

• Pancreatic juice enters the small intestine through the pancreatic duct and bile enters the small intestine through the bile duct.
• Secretion of pancreatic juice is stimulated by the hormones secretin and Cholecystokinin – Pancreozymin (CCK-PZ)
• Bile salts help in emulsification of fats (breakdown of fats into smaller units).
• Pancreatic lipase acts at a pH of 6 and breaks down triglycerides into fatty acids and glycerol.
• The enzyme cholesterol esterase breaks down cholesterol esters and phospholipase breaks down phospholipids.

Role of Lipids in Heart Health and Cholesterol Regulation

Absorption Of Lipids:

• The resynthesized triglycerides in the intestinal epithelial cells cannot pass to lymphatics or to the portal blood as they are insoluble in water.
• Triglycerides get covered with a layer of phospholipid, cholesterol and apoprotein to from the lipoprotein chylomicron.
• Chylomicrons are soluble; they pass out through the intestinal epithelial cell and enter the blood and lymphatics.