Absorption

Question 1

Factors that affect rate of absorption

Answer 1

• surface area
• thickness of separating membrane (btwn food and blood capillaries)
• steepness of conc gradient of individual food substances

Question 2

Adaptations of small intestine

Answer 2

• large SA
• thin separating membrane
• steep conc gradient (large diff in conc)

Question 3

Small intestine

Answer 3

• site of absorption of products of digestion

Question 4

Increase SA (Adaptation)

Answer 4

• villi in inner walls
• numerous folds in wall
• microvilli in the epithelium of villi

Question 5

Thin separating membrane/walls (Adpatation)

Answer 5

• villi: thin walls, 1 cell thick faster diffusion of nutrients into bloodstream

Question 6

Length of small intestine

Answer 6

• 6m
• increase time for absorption
• more time for more nutrients to be absorbed

Question 7

Structure of villus

Answer 7

• lacteal/lymphatic capillary surrounded by many blood capillaries
• many capillaries: carry away absorbed nutrients away quickly
• continual transport of nutrients, maintains conc gradient required for absorption

Question 8

Blood capillary network (Villus)

Answer 8

• transport amino acids and glucose to bloodstream

Question 9

Lacteal/lymphatic capillary

Answer 9

• transport fats to bloodstream arnd body

Question 10

How are nutrients absorbed in small and large intestine

Answer 10

1. Diffusion

2. Active transport

Question 11

Diffusion

Answer 11

• glucose, other monosaccharides, amino acids diffuse into blood capillaries
• glycerol and fatty acids diffuse into epithelium
• combine to form minute fat globules
• enter lacteal

Question 12

Active transport

Answer 12

• glucose, amino acid absorbed by active transport

- lower conc in lumen of small intestine than blood capillaries

Question 13

What happens to undigested and unabsorbed matter?

Answer 13

• stored temporarily in rectum
• discharged as faeces thru anus
• aka egestion (not excretion)