Fat digestion

Question 1

Insulin

Answer 1

a peptide hormone released by the pancreas

Question 2

The cephalic phase of digestion

Answer 2

Begin before food enter the mouth
Brain anticipate through sight, smell or the thought of food

• Flow of saliva from salivary glands to mouth
• Secretion of gastric juice and insulin in anticipation of food
• Lingual lipase secreted into mouth enables some hydrolysis of lipid

Question 3

Stomach

Answer 3

Distensible, muscular sac made up of 3 layers of smooth muscle running in different directions,

–> enable stomach to churn food, physically break it up and mix it with digestive juices

Little absorption - mainly organ of mechanical digestion

Question 4

Fat digestion at stomach

Answer 4

Stomach produce a TAG lipase

- responsible for ~25% of the partial TAG hydrolysis necessary for fat absorption

Question 5

Volume of stomach

Answer 5

50ml when empty

can expand to hold up 1.5L or more

Question 6

Chyme

Answer 6

Partially digested food, cream mixture pounded by stomach and leave to enter small intestine

Question 7

Pyloric sphincter muscle

Answer 7

control rate of gastric emptying

open twice a minute to release ~3 ml of chyme

Question 8

Small intestine structure

Answer 8

• duodenum [25cm], jejunum [2m], ileum [2.5- 3m]
• Inner surface folded into finger-like projections called Villi –> increase surface area for absorption
• Surface area increased further by a brush border: microvilli
• Gall bladder - a reservoir for bile salt produced in liver and send via bile duct

Question 9

the site of much of the absorption of macronutrients

Answer 9

jejunum

Question 10

Villi

Answer 10

projections from epithelial lining of intestine

Question 11

Lacteal

Answer 11

lymphatic capillary that absorb dietary fat

Question 12

Hepatic portal vein

Answer 12

conducts blood from GI tract and spleen to liver

Question 13

Mouth produce which substance for which digestion function

Answer 13

produce lingual lipase for small degree hydrolysis

Question 14

Stomach produce which substance for which digestion function

Answer 14

produce gastric lipase for significant hydrolysis

Question 15

Small intestine produce which substance for which digestion function

Answer 15

Intestinal juice for dilution, lubrication

Question 16

gall bladder produce which substance for which digestion function

Answer 16

bile [pH 7.6] for neutralisation of chyme

bile salt for emulsification of fat

Question 17

Pancreas produce which substance for which digestion function

Answer 17

Pancreatic juice [pH7.9] for neutralisation of chyme

pancreatic lipase for hydrolysis of TAG

phospholipase A2 for hydrolysis of phospholipids