6.1 Digestion

Question 1

What are 3 ways of mechanical digestion?

Answer 1

1) Chewing
2) Churning (stomach muscles squeeze and mix food with digestive juices)
3) Segmentation (contraction & relaxation of non-adjacent segments of circular smooth muscle in small intestine)

Question 2

What is the name of the movement of food? Which muscle type does it?

Answer 2

Peristalsis
With longitudinal smooth muscle

Question 3

Stomach acids

Answer 3

break down macromolecules like proteins, the pancreas releases alkaline compounds to neutralize acids as they enter the small intestine

Question 4

Bile

Answer 4

Bile salts break down fats into smaller pieces, increasing SA for lipase

Question 5

Villi epithelium

Answer 5

1 cell thick, only lets monomers through and mineral ions and vitamins

Question 6

What are the passive transport mechanisms of the epithelium and which monomers are they for?

Answer 6

1) Simple diffusion: very small molecules, non polar, fatty acids
2) Facilitated diffusion: glucose, amino acids

Question 7

What are the active transport mechanisms of the epithelium and which monomers are they for?

Answer 7

Membrane Pumps: Glucose , amino acids (both in special cases)
Endocytosis: big non-monomers

Question 8

Outline starch digestion.

Answer 8

1) Amylase breaks down in mouth
2) pancreatic amylase in the intestines break starch down to maltose or another disaccharide
3) hydrolysis of disaccharide makes monosaccharides (e.g. glucose)
4) can be hydrolysed to make ATP or stored in the liver as glucagon

Question 9

Features of villi? MR SLIM

Answer 9

Microvilli
Rich blood supply
Single cell thick epithelium
Lacteals
Intestine glands/crypts/pits
Membrane Proteins

Question 10

the lymphatic vessels of the small intestine which absorb digested fats are called….?

Answer 10

Lacteals