Histology of Upper GI Tract: Esophagus and Stomach Flashcards Preview

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Flashcards in Histology of Upper GI Tract: Esophagus and Stomach Deck (84):
1

3 functions in the GI Tract

swallowing, digestion, absorption

2

Where does swallowing occur

oral cavity and esophagus

3

Where does digestion occur

small intestine

4

Where does absorption occur

large intestine

5

What is the function of villi

increase surface area for absorption

6

4 Main digestive organs

esophagus, stomach, small intestine, large intestine

7

4 concentric layers

1. mucosa
2. submucosa
3. muscularis
4 serosa/adventitia

8

Where does chemical digestion start

in the stomach

9

3 features of mucosa

epithelium, lamina propria, muscularis mucosa

10

3 features of submucosa

connective tissue that contains glands, blood vessels, and nerves

11

Features of muscularis externa

2/3 layers of smooth muscle

12

Features of serosa

connective tissue that supports and binds organ to other

13

Where is the epithelium stratified squamous

oral cavity, esophagus, anal canal

14

Where is the epithelium simple columnar

stomach, small intestine, large intestine, and rectum

15

Function of epithelium

selective permeable barrier
transport, digestion, absorption
produce hormones

16

Function of lamina propria

where vascular supply comes in
lymphatic nodules present

17

Where is the lamina propria most relevant

small intestine and large intestine

18

What is the nickname for the lamina propria in small intestine and large intestine

Peyer's Patch and GALT

19

Function os muscularis mucosae

increases contact area with food
propel and mix food in GI tract

20

Characteristics of submucosa

dense irregular connective tissue with large blood vessels, lymphatics, and nerves

21

What organs have glands in their submucosa?

esophagus and duodenum

22

What are the folds of mucosa/submucosa in the stomach and called?

rugae

23

What are the folds of mucosa/submucosa in the small intestine called?

plicae

24

What is the function of mucosal glands?

increase secretory capacity

25

What is the function of mucosal villi?

increase the absorptive capacity of digestive tube

26

What would happen if the mucosa was to acidic?

could lose the function of the mucosa

27

What is the function of plicae and rugae?

to increase surface area and help with absorption

28

Where is Meissner's plexus located?

in the submucosa

29

Where is the Myenteric plexus located?

in the muscularis layer

30

T/F Only the jejunum and ileum have a meissner's and myenteric plexus?

F, all segments of the GI tract will have both plexi

31

What are the 2 layers of smooth muscle in the Muscularis Externa

Circular layer and longitudinal layer

32

What is the function of the circular layer?

contraction reduces the lumen and helps move food and propel food thru the organs

33

What is the function of the longitudinal layer?

to make the tube shorter and move food thru the tube

34

What innervation is the voluntary control of the GI tract

Extrinsic (ANS) via sympathetic (decrease motility) and via parasym (increase motility)

35

What nerve innervates the parasympathetic system

vagus via pelivc splanchnic nerves

36

What innervation does involuntary control of the GI tract

intrinsic/enteric system through Meissner's plexus and Myenteric plexus

37

Function of the intrinsic/enteric system

1. peristaltic contractions to move food bolus
2. secretory activity of mucosal/submucosal glands

38

What is the function of the esophagus

carry food down to stomach via peristaltic contractions

39

Function of Lower Esophageal Sphincter

when contracting: help prevent reflux and regurgitation of stomach contents
when relaxing: allow food passage and swallowing

40

Difference between the upper esophagus and lower esophagus

upper part inside the muscularis externa there is skeletal muscle
lower part inside the muscularis externa there is smooth muscle

41

What is the change in mucosa shape at the gastroesophageal junction?

from stratified squamous to simple columnar

42

What layer of the esophagus produces lubricant

mucosal and submucosal

43

What is the function of the upper esophageal sphincter

initiation of swallowing

44

What is the function of the lower esophageal sphincter

prevent gastric reflux

45

What occurs with a person has GERD?

change in epithelium to columnar, chronic esophagitis, dysphagia, fibrosis

46

Barrett's esophagus

when abnormal columnar epithelium replaces the stratified squamous epithelium that is normally in distal esophagus

47

Sliding Hernia

involves esophagus and stomach

48

Paraesophageal hernia

involves only stomach

49

Function of the stomach

chemically process swallowed semisolid fluid

50

What is orad motility?

area: cardia and upper fundus
function: relaxes the sphincter, holding changer where the food is going to go first

51

What is caudad motility?

function: contraction and emptying food and putting it into duodenum

52

Gastric glands

secrete gastric juice

53

What are the 5 major cell types of gastric glands

1. Mucous neck
2. Chief cells
3. Parietal cells
4. Stem cells
5. Gastroenteroendocrine cells

54

What do mucous cells produce

mucins

55

What is the function of the mucin

- hold a lot of water and make a insoluble gel to make a protective layer
- traps bicarbonate
- neutralize microenvironment

56

What do chief cells secrete

pepsinogen

57

Function of pepsinogen

proenzyme stored in zymogen and is converted to pepsin in acidic environment

58

When is pepsinogen stimulated

by feeding, after fasting

59

What do parietal cells produce

make HCl and Intrinsic Factor

60

What occurs if you don't make enough intrinsic factor?

wont be able to absorb B12

61

What occurs if something attacks parietal cells?

can't make HCl and can't absorb B12

62

Autoimmune gastitis

destruction of parietal cells causing reduction in hydrochloric acid in gastric juice and less intrinsic factor resultingin B12 deficiency and pernicious anemia

63

What parasympathetic mediator and what peptide can help stimulate HCl

Acetylcholine and gastrin

64

Where are Ach and gastrin produced?

enteroendocrine cells of pyloric antrum

65

Function of Ach in stomach

help secrete HCl

66

Function of gastrin in stomach

send signal to other cells to upregulate their function to help digestion (upregulate parietal cells)

67

Where do Helicobactor Pylori thrive?

in the mucus epithelium of the stomach especially pyloric antrum

68

What are S/S of H. pylori?

peptic ulcers and adenocarcinoma

69

What is produced by gastoenteroendocrine cells?

peptide hormones

70

What is the largest endocrine organ in the body and why

GI system- because so many gastroenteroendocrine cells that produce peptide hormones

71

What is secretin

a peptide hormone released by duodenal glands of Lieberkuhn

72

When is secretin released

when gastric contents enter the duodenum

73

Function of secretin

- stimulate pancreatic and duodenal bicarbonate and fluid release
- regulate pH of duodenal contents

74

What occurs when secretin and CCK work together

stimulate growth of exocrine pancreas

75

What cells does secretin stimualte

chief cells to secrete pepsinogen

76

What peptide hormones does secretin inhibit

gastrin- to reduce HCl secretion and reduce acidity

77

What cells produce gastrin

G cells

78

Main functions of gastrin

- stimulate production of HCl in parietal cells
- activate CCK to stimulate gallbladder contraction

79

What are the 4 peptide hormones

CCK, Glucose-dependent insulinotropic peptide, Motilin, Ghrelin

80

Function of CCK

in duodenum, stimulate gallbladder contraction and relaxation when protein and fat chyme come thru

81

Function of glucose dependent insulinotropic peptide

in duodenum, stimulates insulin release when glucose detected in small intestine

82

Function of Motilin

in upper small intestine, stimulate gastrointestinal motility

83

Function of Ghrelin

in stomach, stimulates secretion of growth hormone
*increased during fasting triggering hunger by acting in hypothalamic feeding centers

84

Difference between the lamina propria and mucosa/submucosa in pylorus

lamina propria has no elastic fibers and the submucosa does have elastic fibers