week 10 - digestion

Question 1

what are the 4 major layers of digestion?

Answer 1

1. mucosa (inner lining)
2. submucosa (blood vessels + lymphatic vessels)
3. muscularis externa (smooth muscle cells)
4. serosa (covers 3)

Question 2

what parts of the body do mechanical processing?

Answer 2

• mouth
• oesophagus (peristalsis)
• stomach (peristalsis)
• small intestine (peristalsis)

Question 3

what is the process of peristalisis?

Answer 3

1. contraction of circular muscles behind bolus
2. contraction of longitudinal muscles ahead of bolus
3. contraction of circular muscle layer forces bolus forward

Question 4

what parts of the body do chemical digestion?

Answer 4

PROTEINS AND CARBS
- stomach: protein > polypeptides > peptides > amino acids
- mouth: polysaccharides > trisaccharides
- small intestine: disaccharides > monosaccharides

FATS
- mouth: lipids/fat/triglycerides >
- small intestine: monoglyceride + fatty acids

Question 5

what happens during protein absorption?

Answer 5

• proteins are absorbed as amino acids
• travel in blood to liver

Question 6

what happens during carb absorption?

Answer 6

• absorbed as monosaccharides
• travel in blood to liver

Question 7

what happens during lipid absorption?

Answer 7

• surrounded by bile to form molecules
• re-packaged into chylomicrons

Question 8

what happens during water absorption?

Answer 8

• movement across epithelium involves passive flow down osmotic gradient

Question 9

what is catabolism?

Answer 9

• breakdown larger organic molecules into smaller ones
• release energy

Question 10

what is anabolism?

Answer 10

• use simple molecules to make larger ones
• consume energy

Question 11

what is glycolysis (in regard to glucose catabolism)?

Answer 11

breakdown of glucose

Question 12

steps of glucose anabolism?

Answer 12

1. glycogenesis: storage of glucose in liver
2. gluconeogenesis: production of glucose when levels are low

Question 13

what is metabolism controlled by?

Answer 13

thyroid gland