2. Digestion of carbs, fats + proteins

Question 1

glucose + galactose

Answer 1

Lactose

Question 2

glucose + fructose

Answer 2

Sucrose

Question 3

glucose + glucose

Answer 3

Maltose

Question 4

Digestion of Carbs Starts In the Mouth

Answer 4

Polys + oligos are digested by glycosidases Saliva contains the enzyme α-amylase digests random α1-4 glycosidic linkage but most go through undigested at this stage

Question 5

Further Digestion of Carbs in the Small Intestine

Answer 5

stomach acid is neutralized in the small intestine pancreatic α-amylase continue to digest oligos and polys to dis

Question 6

Absorption of Monos

Answer 6

mostly occurs in the duodenum and upper jejunum pumped from the intestinal cells into the portal circulation by GLUT2

Question 7

Emulsification Of Dietary Lipids

Answer 7

Bile acids act as a detergent result in the formation of a mixed micelle

Question 8

TAGs + Pancreatic Lipase

Answer 8

Digests TAGs to 2 x FAs + 1 monoacylglycerol

Question 9

Phospholipid Digestion

Answer 9

release of active Phospholipase A2 removes one of the two FAs from a phospholipid leaves a lysophospholipid the remaining FA is removed from the head group by lysophospholipase

Question 10

Absorption of Lipids

Answer 10

mixed micelles approach the “brush” border of the intestinal cells (entrocytes)

they are absorbed passively by diffusion

Question 11

Digestion of Proteins in Stomach

Answer 11

Hydrochloric Acid denatures protein

Pepsin digests up to 20% of ingested amide bonds

Question 12

Lactose intolerance

Answer 12

missing lactase undigested lactose moves into GI tract is digested by anaerobic bacteria these produce gas patient suffers bloating, flatulence, cramps and diarrhoea

Question 13

Gallstone

Answer 13

blockage of bile duct no bile acids fat digestion badly affected

Question 14

Phases of digestion

Answer 14

1) Cephalic phase 2) Gastric phase 3) Intestinal phase

Question 15

Cephalic Phase

Answer 15

Sight/smell/thought of food Cerebrum Medulla Oblongata

Question 16

Gastric Phase

Answer 16

Parasympathetic impulses via vagus nerve Distension of stomach as food enters Food buffers gastric juices Increase in stomach pH Stimulation of G cells: = increased gastric juice secretion = increased peristalsis of stomach wall = relaxation of pyloric sphincter

Question 17

Intestinal phase

Answer 17

Entrance of acidic chyme in to duodenum Directly stimulates enteroendocrine cells release of 2 hormones: Secretin = inhibits release of gastric juice Cholecystokinin= inhibits emptying of stomach

Question 18

What % of total mass of pancreatic excretions does PL represent

Answer 18

2-3%