Gi I

Front 1

What is the mucosa? What are 3 major functions? What are 3 layers?

Back 1

moist epithelial layer that lines the lumen of the alimentary canal
functions: 1. secrete mucus 2. absorb end products of digestion 3. protect against infectious disease
layers: 1. lining epithelium 2. lamina propria 3. muscularis mucosae

Front 2

What are the 7 layers of the GI system, from outer to inner?

Back 2

1. serosa
2. longitudinal muscle
3. circular muscle
4. submucosa
5. mucosal muscle
6. mucosa
7. epithelial lining

Front 3

What does the epithelia lining of the mucosa consist of?

Back 3

simple columnar epithelium and mucus-secreting goblet cells

Front 4

What is the Lamina Propria?

Back 4

loose areolar and reticular connective tissue that nourishes the epithelium and absorbs nutrients

Front 5

What is the muscularis mucosae?

Back 5

smooth muscle cells that produce local movements of mucosa

Front 6

What is the submucosa?

Back 6

dense connective tissue containing elastic fibers, blood and lymph vessels, lymph nodes, and nerves

Front 7

What is the muscularis externa responsible for?

Back 7

segmentation and peristalis

Front 8

What is the serosa replaced by in the esophagus?

Back 8

the fibrous adventitia

Front 9

What do Brunner's glands secrete?

Back 9

bicarbonate rich mucus

Front 10

What is the serosa?

Back 10

the protective viseral peritoneum

Front 11

How does the smooth muscle in the GI work as a functional syncytium?

Back 11

it has lots of gap junctions that make longitudinal movements down the muscle fast; and works as if it were a single cell.

Front 12

What do slow waves represent in terms of the electrical activity of the GI system? How many are there in the stomach, duodenum, and ileum?

Back 12

resting, NOT action potential
3 in stomach
12 in duodenum
8-9 in ileum

Front 13

What are slow waves induced by?

Back 13

Interstitial Cells of Cajal (electrical pacemakers) within smooth muscle fibers

Front 14

What causes spikes in the electrical activity of the GI system?

Back 14

Entrance of Ca2+ through SLOW ca2+/Na+ channels

Front 15

What aspects of the GI system does the pelvic nerves innervate?

Back 15

parasympathetic: distal half of large intestine, external anal sphincter

Front 16

What are the principle effects of the myenteric/auerbach plexus? (4)

Back 16

1. increased tonic contraction
2. increaed intensity of rhythmic contractions
3. slightly increased rate of rhythmic contractions
4. increased movement of peristaltic waves

Front 17

What are the principle effects of the submucosal/meissner plexus? (3)

Back 17

1. control of local intestinal secretion
2. control of local absorption
3. local contraction of the submucosal muscle (infolding)

Front 18

What are short GI reflexes mediated by?

Back 18

local enteric plexuses

Front 19

What are long GI reflexes mediated by?

Back 19

involves CNS centers and extrinsic autonomic nerves

Front 20

Why does gastrin bind to cholecystokinin B receptors?

Back 20

to stimulate the release of histamines in enterochromaffin-like cells

Front 21

What does Gastrin do? What is it released by?

Back 21

stimulates secretion of HCl; released by G cells in stomach duodenum, and pancreas, induces the insertion of K+/H+ ATPase pumps into the apical membrane of parietal cells (which in turn increases H+ release)

Front 22

What does Ghrelin do? What is its counterpart

Back 22

stimulates hunger; counterpart is leptin, which is stimulated by adipose cells and induces satiation

Front 23

What does Cholecystokinin (CCK) do? Where is it made, and where is it secreted?

Back 23

stimulates the digestion of fat and protein; made and secreted in the duodenum

Front 24

What does Secretin do? Where is it produced?

Back 24

regulates pH of duodenum
produced in the Crypts of Lieberkuhn

Front 25

What does Gastric Inhibitory Peptide (GIP) do?

Back 25

induces insulin secretion, at high levels helps to regulate pH

Front 26

What organs do the inferior and superior mesenteric arteries serve?

Back 26

small and large intestines

Front 27

What do peristaltic movements require? Why is peristaltic movement directional?

Back 27

myenteric plexus; myenteric plexis is polarized, easier to travel from mouth to rectum

Front 28

What centers in the brain is linked to chewing? (3)

Back 28

reticular formation
hypothalamus
cortical taste centers

Front 29

What is deglutition?

Back 29

swallowing

Front 30

What is GERD?

Back 30

when there isn't enough town in the lower esophageal sphincter and acids rise up into the esophagus

Front 31

What is the term for the entry of food causing dilation in the stomach?

Back 31

vasovagal reflex

Front 32

What is responsible for the export of food from the stomach?

Back 32

the pyloric pump

Front 33

What are propulsive movements like in the small intestine?

Back 33

weak, 3-5 cm

Front 34

What controls peristalisis in the small intestine

Back 34

- Gastroenteric reflex (initiated by stomach distension and transmitted through myenteric plexis)
hormones:
+ Gastrin, CCK, Insulin, Motilin, Serotonin
- Secretin, glucagon

Front 35

What are mixing/segmentation contractions induced by in the small intestine?

Back 35

induced by stretching

Front 36

What does the maximal frequency of mixing/segmentation contractions depend on? (2)

Back 36

electrical slow waves and the myenteric plexus

Front 37

What is the function of the ileocecal valve? What does the ileocecal valve require?

Back 37

prevents backflow from colon to ileum; there is a gastroileal reflex and also requires myenteric plexus

Front 38

What are the movements of the large intestine like?

Back 38

sluggish, modified form of peristalsis where 20 cm contract at a time

Front 39

What are mixing contractions called in the large intestine?

Back 39

haustrations (baglike protrusions)

Front 40

What secretory glands are throughout the GI mucous?

Back 40

goblet cells (cingular glands)

Front 41

What type of glands are cardiac glands?

Back 41

mucous secreting

Front 42

What do oxyntic (parietal) cells secrete?

Back 42

HCl, intrinsic factor

Front 43

What do peptic (chief) cells secrete?

Back 43

pepsinogen

Front 44

What are gastrin secreting glands sensitive to?

Back 44

pH

Front 45

What are the 3 types of tubular glands?

Back 45

cardiac, oxyntic, and pyloric

Front 46

What are the 2 types of glands in crypts?

Back 46

brunner's
lieberkuhn (large and small intestine)

Front 47

What is intrinsic factor responsible for?

Back 47

absorption of B12

Front 48

How is HCl secreted?

Back 48

cell actively leaks Cl- and this is compensated by leaking K+ as well

Front 49

What 3 hormones control secretion of HCl?

Back 49

gastrin
histamine
acetylcholine (parasympathetic)

Front 50

How is pepsinogen converted to pepsin?

Back 50

by HCl hydrolysis

Front 51

What releases pepsinogen? What is it?

Back 51

released by chief cells in the stomach; inactive form of pepsin; protein digesting enzyme

Front 52

What is gastritis? What can it be caused by?

Back 52

inflammation of the stomach wall. due to irritants such as cigarettes, caffeine, alcohol

Front 53

What are 3 consequences of chronic gastritis?

Back 53

mucosal reduction
achlorhydia (inability to produce HCl)
pernicious anemia (inability to absorb B12)