Question

Please answer all 4 questions thank you!

1) During lipid digestion, emulsification occurs in the __________________, whereas formation of chylomicrons occurs in the _____________________.

		lumen of the small intestine; lacteals
		epithelial cells that line the wall of the small intestine; lacteals
		lumen of the small intestine; lumen of the large intestine
		lumen of the small intestine; epithelial cells that line the wall of the small intestine
		lumen of the stomach; lumen of the small intestine

2) Mass movements of fecal matter through the colon are triggered by ___________________.

		pressure applied to the ileocecal valve as undigested matter enters the cecum.
		bacteria that reside in the colon
		sympathetic innervation
		the gastrocolic and duodenocolic reflexes that are triggered by digesta entering the stomach and duodenum.
		the hormone, secretin

3) Individual amino acids and glucose enter the cells that line the lumen of the digestive tract via ___________________.

		primary active transport
		sodium-linked secondary active transport
		simple diffusion
		facilitated diffusion
		endocytosis

4) Digestion can be divided up into mechanical and chemical processes. The primary function of mechanical processes is to

		make food particles small enough so that they can be absorbed.
		make food particles smaller so that more surface area is exposed to digestive chemicals.
		break bonds between atoms in molecules.
		activate digestive enzymes.
		separate digestible from indigestible materials.

Answer 1

1.(A) Lumen of the small intestine

(B)Epithelial cells that line the wall of small intestine

Explanation:- when fat globules reaches small intestine ,bile produced by liver comes into the duodenum . Bile break down the large fat globules into small tiny droplets in the lumen of small intestine so as to increase the surface area on which enzymes can act

Digested fat(fatty acids and glycerol) get absorbed into the epithelial cells lining the small intestine called enterocytes. In the endoplasmic reticulum of enterocytes,formation of chylomicrons occurs.

2. The gastrocolic and duodenocolic reflexes that are triggered by digesta entering the stomach and duodenum.

Explanation:- when food enters into stomach and duodenum, stretching of the wall of gut occurs. This triggers a physiological reflex called gastrocolic and duodenocolic reflex that controls the motility(peristalsis) of lower gastrointestinal tract following a meal.

3. Sodium- linked secondary active transport

Explanation:- in wall wall of small intestine , glucose and amino acids individually enter into the cell(enterocytes) by sodium dependent glucose cotransporter and sodium dependent amino acid cotransporter. Thus they are sodium linked secondary active cotransporter.

4. Make food particles smaller so that more surface area is exposed to digestive chemicals.

Explanation:- in mechanical digestion, food is physically broken down into small particles to increase its surface area so that enzymes can properly act on it. This occurs via the act of chewing (mouth), churning (stomach) and segmentation (small intestine).