Upper GI Structure/Function Flashcards Preview

GI > Upper GI Structure/Function > Flashcards

Flashcards in Upper GI Structure/Function Deck (50)
Loading flashcards...
1
Q

What is semi-fluid of partially digested food in the stomach called?

A

chyme

2
Q

Where is voluntary muscle located in the GI tract?

A

upper 1/3 of esophagus

3
Q

What are the 4 general layers of the GI tract? (luminal inward)

A

Mucosa
Submucosa
Muscularis Externa
Adventitia/Serosa

4
Q

What are the thee layers of the mucosa?

A

Epithelium
Lamina Propria
Muscularis mucosae

5
Q

What is the role of the mucosal epithelium? (general)

A

mucosal function

6
Q

What is the role of the lamina propria? (general)

A

supports epithelium, contains lymphocytes and plasma cells

7
Q

What is the role of the muscularis mucosae? (general)

A

local movements and folding of mucosa

houses capillaries

8
Q

Waht is submucosa? What is it’s function?

A

layer of loose collagenous and adipose tissue
supports the mucosa
contains large blood vessels and lymphatic vessels

9
Q

Where does the submucosa contain mucous secreting glads?

A

esophagus and duodenum

10
Q

What part of the enteric nervous system is in the submucoa? What type of innervation is this?

A

submucosal (meissner’s) plexus

parasympathetic ganglia

11
Q

Which layer of the muscularis externia is internal? external?

A

internal: circular
outer: longitudinal

12
Q

What is the role of the muscularis externa?

A

peristalsis

13
Q

What type of muscle is muscularis externa?

A

smooth

14
Q

What part of the enteric nervous system is in the muscularis externa? what does it control?

A

myenteric (auerbach’s) plexus

control’s peristalsis

15
Q

What is the adventitia/serosa?

A

outermost covering of the GI tract

16
Q

Define adventitia

A

loose connective tissue layer surrounding he GI tract wtihin he peritoneal cavity

17
Q

Define serosa

A

simple squamous epithelium (mesothelium) along with conntective tissue that covers the GI tract within the peritoneal cavity
(epithelium secretes serous fluid to lubricate)

18
Q

What neurotransmitters does the enteric nervous system use?

A

Ach
NE
serotonin

19
Q

What does the submucosal/meissner’s plexus do?

A

controls mucosal movement, secretory activity and blood flow

20
Q

What does the myenteric/auerbach’s plexus do?

A

controls peristaltic gut movements

21
Q

What type of mucosa is in the upper gi tract and anus? function?

A

stratified squamous, non-keratinized, contains langerhans cells
protective

22
Q

What type of mucoas is found in the stomach? function?

A
simple columnar epithelium
thick mucous, traps bicarbonate ions
gastric pits
secretory
contains abundance of tubular glands
23
Q

What type of mucosa is found in the SI? function

A

absorptive

mucosa is folded into villi to maximize surface area

24
Q

What type of mucosa is found in the LI? function?

A

absorptive/protective

produces mucin and absorbs water

25
Q

What secretes mucous to help propel food down the esophagus?

A

esophageal cardiac glands

26
Q

Where are esophageal glands located? function?

A

submucosa
arranged in acini
contain mucous cells and serous cells
secrete pepsinogen & lysozyme

27
Q

Where is the adventitia/serosa border of teh esphoagus?

A

the diaphragm

28
Q

What cell types make up the GEJ

A

stratified squamous to simple columnar

29
Q

What are the 2 physiological sphincters of the esophagus

A

pharyngoespophageal-prevents reflux from esophaus to pharynx

gastroesophageal-prevents reflux from stomach to esophagus

30
Q

What are the 4 anatomical regions of the stomach?

A

cardia
fundus
body
pyloris

31
Q

What makes up gastric juice?

A

HCl, pepsin, rennin, gastric lipase

32
Q

Describe the lamina propria of the stomach

A

contains gastric glands

enterochromaffin type cells

33
Q

What do enterochromaffin-type cells do?

A

secrete histamine in response to vagus nerve to increase acid secretion

34
Q

How many layers of muscle are in the stomach?

A

3

circular, oblique, longitudinal

35
Q

What are gastric pits?

A

pitted surface of mucosa

36
Q

What are gastric glands?

A

tupular columns of epithelial cells

3 regions: isthmus, neck, base

37
Q

What are the 6 cell typesof simple columnar epithelium in gastric glands?

A
  1. surface mucous/lining cells (gastric pit)
  2. parietal cells (isthmus, neck & base)
  3. neck mucous cells (neck & base)
  4. Chief (peptic) cells (base)
  5. Enteroendocrine cells (base)
  6. Stem/regenerative cells (neck)
38
Q

What type of mucous is secreted by surface lining cells? mucous neck cells?

A

surface lining cells-thick & dense, adheres to mucosa and protects against acid
mucous neck cells-soluble, lubes stomach to aid digestion

39
Q

What substances do enteroendocrine cells secrete?

A
usually a single bioactive agent
G-cells: gastrin
EC cells: serotonin
D cells: somatostatin
A cells: enteroglucagon
ECL cells: histamine
can act paracrine or endocrine
40
Q

What do parietal cells secrete? features of parietal cells?

A
HCl
Intrinsic factor
secretory cnaliculous-makes pyramidal, microvilli extend into
Tubulovesicular network
lots of mitochondria
41
Q

What do chief cells secrete? features of chief cells?

A

pepsinogen, rennin, gastric lipase (from zymogen secretory granules)
lots of RER & golgi
base of gastric glands
binding to secretin leads to rapid exocytosis of secretory granules
vagus nerve stimulates enzyme release

42
Q

Describe the regenerative stem cells of the gastric glands

A

found in neck of gastric gland
mitotic figures
daughter cells differentiate and migrate

43
Q

What is mucosal restitution?

A

surface epithelium repair after injury by rapid migration of epithelial cells lying deep in the protected enrionment of the pits

44
Q

What type of glands are found in the fundus/body?

A

straight tubular

45
Q

What types of glands are found in the pylorus?

A

branched, mucous neck cells predominate

46
Q

What type of glands are found in the cardiac region?

A

shallower gastric pits, highly coiled

47
Q

What is the cephalic phase?

A

brain anticipates meal
parasympathetic signals vagus–>gastrin secretion
30% gastric acid released

48
Q

What is the gastric phase?

A

food enters stomach->distention->increased G cell activity

60% total gastric acid released

49
Q

What is the intestinal phase?

A

Chyme released into duodenum
enterogastric relfex
10% gastric acid released

50
Q

What is the enterogastric reflex?

A

distention of the intestine–>gastric-inhibitory impulses by ENS