Lower GI II

Question 1

______ hydrolyzes starch to form sugars

Answer 1

Amylase

Question 2

Amylase is secreted by glands in the _______ as well as by the ______

Answer 2

mouth, pancreas

Question 3

Starch is hydrolyzed to ________

Answer 3

disaccharides

Question 4

Disaccharides are broken down to __________

Answer 4

monosaccharides

Question 5

the breakdown of disaccharides occurs in _______ of _________

Answer 5

brush border of small intestine

Question 6

Monosaccharides are absorbed by _________

Answer 6

enterocytes

Question 7

The absorption of monosaccharides by enterocytes involves

Answer 7

energy-dependent mediator-specific carriers: Na+-dependent sugar glucose transporter-1 (SGLT-1)

Question 8

Digestion of proteins begins in the ______

Answer 8

stomach

Question 9

Proteins are hydrolyzed to

Answer 9

peptides

Question 10

Digestion of proteins occurs through action of ______ (activated form of ______)

Answer 10

Pepsin (activated form of pepsinogen)

Question 11

The digestion of proteins requires _____ environment of stomach, why?

Answer 11

proteins. Activation of pepsinogen to pepsin occurs in acidic enviroments

Question 12

Polypeptide breakdown to peptides also occurs in the ______ and also occurs in the _______

Answer 12

stomach, small intestine

Question 13

Polypeptide breakdown to peptides in the small intestine involves what enzymes secreted by the ______?

Answer 13

Secreted by the pancreas

• Trypsin
• Chymotrypsin
• Elastase
• Carboxypeptidase

Question 14

Activation of pancreatic proteolytic enzymes is initiated by ______ (______) secreted by ___________

Answer 14

Enteropeptidase (enterokinase)

secreted by Duodenal enterocytes

Question 15

Breakdown of oligopeptides to amino acids occurs in the

Answer 15

intestinal brush border

Question 16

Transport of amino acids into enterocytes is via

Answer 16

carrier mediated process

Question 17

Digestion of lipids begins in the _____

Answer 17

small intestine

Question 18

Lipids enter the small intestine as _______

Answer 18

triglyceride droplets

Question 19

________ emulsifies triglyceride droplets into smaller droplets and releases fatty acids and glycerol

Answer 19

pancreatic lipase

Question 20

Fatty acids and glycerol combine with bile salts to form

Answer 20

micelles (2 nm in diameter)

Question 21

Micelles can transport

Answer 21

• Fatty acids
• monoglycerides
• glycerol
• phospholipids
• cholesterol
• Vitamin A
• Vitamin K

Question 22

_______ splits cholesterol into cholesterol and fatty acids

Answer 22

pancreatic lipid esterase

Question 23

pancreatic lipid esterase splits cholesterol esters into

Answer 23

cholesterol and fatty acids

Question 24

Micelles are _______ absorbed across ______ apical plasma membrane

Answer 24

passively, enterocyte

Question 25

what is required for micelles to be passively absorbed across enterocyte apical plasma membrane

Answer 25

Requires fatty acid binding proteins (FABPs) in apical membrane

Question 26

monoglycerides and glycerol are reesterified in the enterocyte ______ to form ______

Answer 26

SER, Triglycerides

Question 27

The reesterification of monoglycerides and glycerol in the enterocyte SER requires _______ and _____ , which are found in

Answer 27

Acyl-CoA synthetase and acyltransferase - found in membranes of enterocyte SER

Question 28

Triglycerides recombine with proteins (from RER) to form ________

Answer 28

chylomicrons

Question 29

Digestion of carbohydrates begin in the _______

Answer 29

mouth

Question 30

Triglycerides recombine with proteins (from RER) to form

Answer 30

Chylomicrons

Question 31

Chylomicrons are enclosed within membranes in __________, these membranes fuse to the plasma membrane and allow

Answer 31

Golgi Apparatus, exocytosis

Question 32

Chylomicrons enter intercellular spaces and are taken up by __________ ________

Answer 32

central lacteals

Question 33

Central lacteals are blind endings of lymphatic vessels within _______ that forms the content of the intercellular spaces within the _____

Answer 33

Lamina propria, villi

Question 34

Lacteals dump into the large _____ _______ (_____ _____) that carry lymph form the gut tract

Answer 34

lymphatic network (cisterna chyli)

Question 35

After being taken up by the central lacteals chylomicrons will later enter the blood via the

Answer 35

lymph ducts that enter the subclavian veins

Question 36

Proteins and carbohydrates enter the blood vessels in the villi and are transported to the liver via the _____ ____ _____

Answer 36

hepatic portal system

Question 37

Secretory activities of the GI tract are largely controlled by various _______ that, in turn, are under the influence of the contents of the GI tract.

Answer 37

hormones

Question 38

Cholecystokinin site of secretion and in response of

Answer 38

- Upper intestinal mucosa (duodenum) | - Secreted in response to gastric contents

Question 39

Targets and effects of cholecystokinin

Answer 39

- Acts on pyloric sphincter to slow down emptying of stomach - Stimulates bile release from gallbladder - Stimulates secretion of pancreatic enzymes - Competitive inhibitor of gastrins.

Question 40

Site of secretion of gastrin

Answer 40

pyloric-antral portion of stomach

Question 41

Targets and effects of Gastrin

Answer 41

- Stimulates HCl production by gastric parietal ells - Promotes growth of gastric mucosa - Stimulates gastric motility - Stimulates release of insulin by pancreatic beta cells

Question 42

Site of Secretin secretion

Answer 42

- Epithelial cells of duodenum | - Stimulated by acid contents of stomach

Question 43

Targets and effects of Secretin

Answer 43

- Enhances release of insulin by pancreatic Beta Cells | - Stimulates bicarbonate secretion by pancreas

Question 44

The epithelium of the anus is ________ epithelium

Answer 44

stratified squamous epithelium

Question 45

Skeletal muscle returns in the anal canal as the

Answer 45

external anal sphincter

Question 46

What is the difference between internal and external hemorrhoids

Answer 46

internal are part of the internal hemorrhoidal plexus, which is internal to the internal anal sphincter and external hemorrhoidal plexus that is external to the external anal sphincter

Question 47

What are hemorrhoids

Answer 47

Veins connecting the internal and external hemorrhoidal plexuses can become dilated and bulge the mucosa