digestion and absorption

Question 1

what are the two types of breakdown involved in digestion

Answer 1

-physical breakdown
chemical breakdown

Question 2

where does physical breakdown occur

Answer 2

-mouth
-stomach

Question 3

what role does the stomach have in physical digestion

Answer 3

the involuntary smooth muscle lining the stomach wall helps to further breakdown the food and mix it with hydrochloric acid and digestive enzymes.

Question 4

what are the three parts of the small intestine

Answer 4

-duodenum
-jejunum
-ileum

Question 5

what is the ileum

Answer 5

The ileum is a muscular tube which is lined with epithelial cells and enzyme secreting glands.

Question 6

what are the main features of a villus

Answer 6

• rich blood supply
  -large surface area for diffusion ( made larger by micro villi)
  -one cell thick (for short diffusion distance)
  -moist surfaces (to allow substances to dissolve)

Question 7

what is the role of amylase enzymes in digestion and where is it produced

Answer 7

• breaks down starch into sugar
• produced in the salivary glands, pancreas, small intestine

Question 8

what is the role of protease enzymes and where are they produced

Answer 8

• breaks down protein into amino acids
  -produced in stomach, pancreas, small intestine

Question 9

what is the role of lipase enzymes in digestion and where are they produced

Answer 9

• breaks down fats into fatty acids and glycerol
  -produced in pancreas, small intestine

Question 10

describe the cotransport of glucose in the ileum process

Answer 10

a cotransport protein embedded in the basal side of the epithelial cell pumps 3Na+ ions into the blood whilst simultaneously pumping 2K+ ions into the epithelial cell. This results in an electrochemical gradient which favours the movement of Na+ ions from the ileum lumen to the epithelial cells. This means Na+ ions are able to move down a concentration gradient. However because it is a cotransporter glucose is able to bind to the cotransporter. it then moves in to the epithelial cell against the concentration gradient resulting in a higher concentration of glucose molecules in the epithelial cell compared to the blood. Therefore glucose is able to move into the blood via facilitated diffusion.