digestion + absorption of nutrients

Question 1

where is the first point of digestion for carbs + what enzyme does this ?

Answer 1

in the mouth

alpha amylase

Question 2

what cells secrete alpha amylase into the small intestine ?

Answer 2

pancreatic acinarf cells

Question 3

what enzyme does the lower part of the intestines contain ?

Answer 3

maltase

Question 4

what secretion is the pancreas involved in ?

Answer 4

• insulin
• somatostatin
• other endocrine hormones

Question 5

what brakes down starch into maltose ?

Answer 5

1,6-glucosidase

Question 6

what breaks down starch into glucose ?

Answer 6

a-amylase

Question 7

what brakes down lactose into glucose ?

Answer 7

lactase

Question 8

what breaks down sucrose into fructose + glucose ?

Answer 8

sucrase

Question 9

what is the small intestine made of ?

Answer 9

• doudenum
• jejunum
• ileum

Question 10

what is found at the base of the small intestines folds ?

Answer 10

tubular invaginations extending to muscular mucosae

Question 11

what is the name of the crypts of the intestine called ?

Answer 11

lieberkuhn

Question 12

what are the function of the crypts of lieberkuhn ?

Answer 12

generative + secretory functions

Question 13

what are the glands found in the upper duodenum ?

what do they secrete ?

Answer 13

Brunner glands

neutral/ alkaline mucous

Question 14

what is does each mucosal villi ?

Answer 14

• arteriole
• capillary network
• vein
• central lympatic / lacteal

Question 15

how are monosaccharide digested ?

Answer 15

Na glucose coupled transporter at mucosal surface of villi
taken into the endohelium
energy provided by Na/K ATPase pump at basolateral membrane
glucose leaves via GLUT2 transporter at serosal membrane into the interstitium
flows into the liver

Question 16

what releases pepsin ?

Answer 16

chief cells

Question 17

what activates pepsin ?

Answer 17

acid environment in stomach

Question 18

what pancreatic enzymes are activated in the intestine lumen ?

Answer 18

• carboxpeptidas
• trypsin
• chymotrypsin

Question 19

what protein breakdown happens in the stomach ?

what enzymes breaks it down ?

Answer 19

protein to polypeptides

pepsins + carboxypeptidases

Question 20

what protein breakdown happens in the intestine ?

Answer 20

polypeptides to tri + dipeptides

trypsin + chymotrypsin

Question 21

what are the 2 different ways proteins can cross the mucosal membrane ?

Answer 21

via proton co transports

via sodium coupled amino acid co transports

Question 22

how do small peptides cross the mucosal membrane ?
what happens once there inside ?
how do they exit into the basolateral membrane ?

Answer 22

via the proton coupled cotransporter
broken down by intracellular peptidase into amino acids
exit via specific facilitated amino acid transport proteins

Question 23

describe the route of amino acids into + out of the brush boarder

Answer 23

individual sodium coupled proteins enter epithelium via amino acid and sodium coupled co transporter
leave into basolateral membrane via specific facilitated amino acid transport proteins

Question 24

how is hydrogen maintained outside of the epithelium ?

Answer 24

there is a sodium pump on the mucosal membrane that pumps it back out

Question 25

describe the absorption of short chain fats + glycerol

Answer 25

can pass through enterocyte

Question 26

describe the absorption of triglycerides :

Answer 26

• broken down into free fatty acids + monoglycerides
• become embedded in micelles
• passively absorbed into epithelial cells of small intestine

Question 27

how are cholesterol , phospholipids and fat soluble vitamins digested ?

Answer 27

incorporated by chylomicrons

are then transported into circulation by lacteal

Question 28

what are mixed micelles composed of ?

Answer 28

bile salts

mixed lipids e.g fatty acids

Question 29

what are examples of fat soluble vitamins ?

Answer 29

• vitamin A
• vitamin D
• vitamin E
• vitamin K

Question 30

what are examples of water soluble vitamins ?

Answer 30

• vitamin B group
• thiamin B1
• riboflavin B2
• niacin B3
• pyridoxine B6
• folate / folic acid B12
• biotin
• pantothenic acid
• vitamin C

Question 31

how are water soluble vitamins absorbed ?

Answer 31

• has its own membrane transport process into the enterocyte
• are absorbed from small intestine
• folate , biotin, riboflavin can be transported across colonic epithelial cells

Question 32

how are fat soluble vitamins absorbed ?

Answer 32

• carried by micelles to brush border
• leave micelle + diffuse into enterocyte
• inside enterocyte they become incorparted into chylomicrons
• enter blood stream via lacteal