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Flashcards in GI Physiology Deck (44):
1

Inner most layer of GI wall composed of epithelial cells specialized for absorption and secretion.

mucosa

2

Layer of GI wall that consists of collagen, elastin, glands, and blood vessels

submucosa

3

Layers of GI wall that provides motility for GI tract

Circular and Longitudinal Smooth Muscle

4

Outer most layer of GI wall

serosa

5

breaking food in small particles so they are easily broken down by enzymes. occurs in the mouth and stomach

mechanical digestion

6

Enzymes in mouth that helps digest carbs and lipids

amylase (carbs) and lipase (lipids)

7

First step of swallowing

cricopharyngeal relaxation

8

What is different about the layers of the esophagus compared to the rest of the GI tract?

no serosa

9

Enzymes that breakdown proteins in the stomach

pepsin and peptidase

10

What are the three phases of digestion?

cephalic, gastric, intestinal

11

Stimulates the release of pancreatic juice and weak contractions of the gallbladder during the cephalic and gastric phases of digestion

vagus nerve

12

What induces the release of cholecstokinin?

fatty, protein-rich chyme

13

What induces the release of secretin by the enteroendocrine cells of the duodenal wall?

acidic chyme

14

What induces the release of pancreatic juice?

CCK and secretin

15

Required for the absorption of B12

intrinsic factor

16

Protects gastric mucosa from HCl

mucus

17

Cells found in the body of the stomach that secrete pepsinogen

chief cells

18

Cells found in the body of the stomach that secrete HCl and intrinsic factor

parietal cells

19

Secreted by G cells in stomach in response to eating. Stimuli include proteins, distention of stomach, and vagal stimulation

gastrin

20

Promotes H+ secretion by gastric parietal cells. Stimulates growth of gastric mucosa

gastrin

21

Released from vagus nerve. Binds to receptors on parietal cells. Produces H+ secretion by parietal cells. Atropine blocks muscarinic receptors on parietal cells

ACh

22

Released from mastlike cells in gastric mucosa. Binds to H2 receptors on parietal cells. Produces H+ secretion by parietal cells

histamine

23

Most common cause of upper GI bleeding?

duodenal ulcers

24

Type of motility where circular muscle contracts sending chyme in both directions. Intestine then relaxes allowing chyme to merge back together

segmentation

25

Type of motility where longitudinal muscle contracts propeling chyme along small intestine. Simultaneously, portion of intestine caudal to bolus relaxes

peristaltic

26

Controls contractile, secretory, and endocrine functions of GI tract. Sends information directly to smooth muscle, secretory, and endocrine cells

Intrinsic Innervation

27

Name for the numerous openings of gastric mucosa where the gastric glands empty into

gastric pits

28

Largest internal organ

liver

29

Supplies majority of blood supply to the liver. Brings venous blood rich in nutrients from digestive tract. High blood flow

hepatic portal vein

30

Name of structures where hepatocytes are in contact with blood in the liver. They fxn as capillaries and are arranged to form functional units (lobules)

sinusoids

31

Found in people who abuse alcohol because alcohol suppresses citrate cycle and thereby impairs gluconeogenesis from aminoacids.

hypoglycemia

32

What is the majority of cholesterol in the liver converted into?

bile salts

33

Necessary for digestion and absorption of lipids in small intestine. Emulsify lipids to prepare them for digestion

Bile salts

34

Detectable when the total plasma bilirubin > 2mg/dl

jaundice

35

good diagnostic test for obstructive jaundice

conjugated bilirubin

36

What is the pathophysiologi mechanism behind the development of varices and ascites associated with cirrhosis?

Cirrhosis leads to scar tissue which can obstruct blood and bile flow. Obstruction of hepatic venous blood flow can increase pressures

37

Main duct (Wirsung) runs the entire length of pancreas. Joins CBD at the ampulla of Vater

pancreatic duct

38

Acts on the acid producing parietal cells and indirectly decreases stomach acid production by preventing release of gastrin, secretin and histamine.

somatostatin

39

only digestive enzyme secreted by the pancreas in an active form
functions optimally at a pH of 7. hydrolyzes starch and glycogen to glucose, maltose, maltotriose, and dextrins

amylase

40

Finger-like projections of the small intestinal mucosa

villi

41

Tiny projections on luminal membrane of each intestinal cell. Give the apical region striated appearance called brush border

microvilli

42

primary site for the removal of water and electrolytes and the storage of feces

transverse colon

43

Tubular glands located in the mucosa of the large intestine that are responsible for mucus secretion

crypts

44

What blocks the passage of feces and maintains continence?

contraction of internal anal sphincter and puborectalis muscle