Lecture 31 - GI

Question 1

mucosa

Answer 1

innermost

• epithelial lining cells
• lamina propria
• muscularis mucosae

Question 2

submucosa

Answer 2

loose tissue; contains blood vessels, nerves, lymphatics

Question 3

muscularis propria (muscle proper)

Answer 3

inner circular muscle
outer longitudinal muscle
(Squeeze and propel)

Question 4

serosa

Answer 4

thin outer lining

Question 5

layers of GI

Answer 5

mucosa
submucosa
muscularis propria
serosa

Question 6

layer of bowel

Answer 6

MUCOSA: lumen to epithelium, lamina propria, muscularis mucosa
SubMucosa: Clear space
Circular around: inner circulars, longitudinally arranged fiber
Serosa then adventisial

Question 7

two main plexi in gi tract

Answer 7

submucosal plexus

myenteric plexus

Question 8

GI tract NS innervation

Answer 8

CNS and ENS (enteric nervous system, unique to gut)

Question 9

ENS nerves arise where

Answer 9

in GI tract, connect to CNS but also have intrinsic set of nerves

Question 10

“second brain”

Answer 10

ENS – colloquial

Question 11

PS input to the gut is at what level

Answer 11

craniosacral

Question 12

craniosacral nerves do what

Answer 12

leave CNS and dont interact with another neuron until they reach the enteric system

Question 13

sympathetic NS nerves arise where

Answer 13

thoracolumbar

Question 14

thoracolumbar nerves do what

Answer 14

synapse in prevertebral ganglia, THEN they go to the gut and GI tract

Question 15

does enteric need CNS

Answer 15

no, it can function without.

EX: quadraplegic people still have functional GI tract

Question 16

gi tract innervation with different plexi

Answer 16

myenteric plexus is well represented throughout, submucosal you dont see until small and large intestine

Question 17

submucosal plexus really important for what

Answer 17

digestion

Question 18

esophagus function

Answer 18

convey food from mouth to stomach

Question 19

key structural features of esophagus

Answer 19

1) epithelial cells are stratified squamous (non keratinized)
2) varying muscularis propria
3) no serosa

Question 20

variance of muscularis propria in esophagus

Answer 20

upper 1/3 skeletal
middle 1/3 skeletal and smooth
lower 1/3 smooth

Question 21

esophagus located where

Answer 21

posterior mediastinum

Question 22

where does vagus travel

Answer 22

alongside esophagus and wraps around stomach

Question 23

histologically, what changes the most from one part of gi to another

Answer 23

the epithelium

Question 24

lower esophageal sphincter is not really a

Answer 24

sphincter - really a high pressure zone to keep acid from going into esophagus

Question 25

function of stomach

Answer 25

begin digestion mechanically and chemically converting food into chyme

Question 26

structural features of stomach

Answer 26

1) epithelium: glands with specialized cells | 2) muscularis propria: 3 layers (oblique layer)

Question 27

specialized cells in epithelium of stomach stomach

Answer 27

``` parietal cells (secrete acid; intrinsic factor) chief cells (secrete pepsinogen) G cells (secrete hormone gastrin) mucous cells (protect, lubricate mucosa) ```

Question 28

stomach can be divided into what two parts

Answer 28

fundus and body secretion reservoir and then distal antrum (mixing and grinding)

Question 29

where is acid made

Answer 29

promixal part of stomach

Question 30

where is gastrin made

Answer 30

antrum

Question 31

which comes first, acid or gastrin

Answer 31

first acid, then gastrin

Question 32

glands in stomach

Answer 32

fundic, pyloric, cardias

Question 33

fundic glands

Answer 33

- fundus and body of stomach | - long, branched glands with mucous, parietal, chief and endocrine cells

Question 34

pyloric glands

Answer 34

- antrum and pyloric areas | - long, branched glands consisting almost exclusively of mucous cells and endocrine cells (G cells)

Question 35

cardiac glands

Answer 35

- proximal stomach, just past the GE junction. - short, branched tubular glands consisting mainly of mucous cells * not very functional

Question 36

common epithelial aspects of stomach

Answer 36

have pits in glands that is lined with mucous producing cells to protect the stomach from acid

Question 37

what distinguishes the different glands

Answer 37

the cells BELOW the pits!

Question 38

gastric fundic gland cell types from top to bottom

Answer 38

mucous, parietal (acid), ECL cell (histamine), chief cells (pepsinogen)

Question 39

gastric epithelial cells

Answer 39

``` foveolar mucous neck parietal cells chief cells endocrine stem ```

Question 40

foveolar cells

Answer 40

located at surface; mucous cells with faint, pink cytoplasm; rectangular shape

Question 41

mucous neck cell

Answer 41

located at base of gastric pits; pale mucous vacuoles

Question 42

parietal cells

Answer 42

located lower in fundic gland; eosinophilc cytoplasm with central nucleus (“fried egg” appearance); eosinophilic cytoplasm (mitochondria); invaginations of the plasma membrane *LOVES THESE*

Question 43

chief cells

Answer 43

located near parietal cells; pyramidal cells with basophilic cytoplasm (numerous ribosomes); zymogen granules in apical cytoplasm

Question 44

Endocrine cells

Answer 44

seen with special immunohistochemical stains; eosinophilic secretory granules. Ex: ECL

Question 45

stem cells

Answer 45

Located in mucous neck region

Question 46

what surface is proton pump on

Answer 46

apical

Question 47

how do we fit more proton pumps in the cells

Answer 47

by making folds

Question 48

production of acid by parietal stimulated by

Answer 48

acetylcholine, histamine, and gastrin

Question 49

upper endoscopy takes you until

Answer 49

end of duodenum

Question 50

colonoscopy takes you to

Answer 50

upper colon