Histology- Tubular GI

Question 1

Four layers of the wall of the alimentary canal

Answer 1

• Mucosa: Containing epithelium, lamina propria, and muscularis mucosa
• Submucosa: dense conn tissue
• Muscularis Externa: smooth muscle
• Serosa: squamous epithelium

Question 2

Three principle functions of the mucosal layer?

Answer 2

• Secretion
• Absorption
• Protection

Question 3

Submucosa functions

Answer 3

Blood and Lymph Vessels are here, nerve plexus, occasional glands

Question 4

Muscularis external function

Answer 4

contractions of inner circular layer compress and mix components in the lumen, outer longitudinal layer propels food by shortening the tube. Rhythmic contractions produce peristalsis

Question 5

What controls peristalsis

Answer 5

enteric nervous system

Question 6

Lumen of the esophagus looks like what?

Answer 6

Highly involuted and convoluted

Question 7

Epithelial layer of the esophageal mucosa is made up of what kinds of cells

Answer 7

SSE Nonkeratinized

Question 8

GALT located in what layer of esophagus

Answer 8

Mucosa

Question 9

Upper third of the muscularis externa of the esophagus is all what type of muscle?

Answer 9

Skeletal muscle

Question 10

Middle third of esophageal muscularis externa

Answer 10

mixed skeletal and smooth

Question 11

Lower third of esophageal muscularis externa?

Answer 11

All smooth

Question 12

Upper and lower esophageal sphincters made up of what type of muscle

Answer 12

smooth

Question 13

Layers in the stomach wall

Answer 13

M/ S/ MP/S 
Mucosa 
Submucosa
Muscularis External
Serosa

Question 14

Mucosa of the stomach has what type of epithelium>

Answer 14

Non-ciliated columnar

Question 15

Four regions of the stomach

Answer 15

• Cardia
• Fundus
• Body
• Antrum

Question 16

What is the overall function of the stomach

Answer 16

digestion…not absorption

Question 17

Unique features of stomach epithelium?

Answer 17

Composed entirely of pale staining mucous cells called surface mucous cells.

Question 18

What are gastric pits?

Answer 18

Mucosal surface is studded with small holes, called gastric pits, where the epithelium invaginates into the lamina propria.

Question 19

What do surface mucous cells of the stomach epithelium produce

Answer 19

alkaline mucous to protect the stomach lining

Question 20

What are the five cell types within gastric glands

Answer 20

• Mucous neck cells
• Chief Cells
• Parietal Cells
• Enteroendocrine cells
• Stem cells

MCPES

Question 21

Chief cells found where

Answer 21

Deep part of gastric gland. Appear very basophilic.

Question 22

What do chief cells secrete

Answer 22

Pepsinogen, the inactive form of pepsin

Question 23

Parietal cells found where>

Answer 23

most numerous in the upper part of the gland

Question 24

What do parietal cells secrete?

Answer 24

HCL and intrinsic factor

Question 25

Parietal cells look like what

Answer 25

Pyramidal, red/pink on H&E

Question 26

Cell division in the stomach occurs where?

Answer 26

Isthmus

Question 27

Surface mucous cells live how long

Answer 27

3-5 days

Question 28

What is the difference between a mammillated fold and a rugae?

Answer 28

Mamillated folds are small elevations of mucosa only. | Rugae elevations contain mucosa and submucosa

Question 29

Three sections on Small bowel in order

Answer 29

duodenum, jejunum, ileum

Question 30

What are the 3 modifications present in the Small intestine to increase surface area?

Answer 30

1) Plicae Circularis- permanent transverse folds of the mucosa, contains a core of submucosa, Increases surface area by three fold 2) Villi- increase surface area 10 fold 3) Microvilli- increase surface area 100 fold

Question 31

Cell type in small intestine?

Answer 31

Epithelium is simple columnar and made up of 6 cell types. They are: 1) Enterocytes- primary absorptive cell, attached to neighboring cells by tight junctions, also secrete water and electroloytes 2) Goblet cells 3) Paneth Cells- found in the base of crypts, basal basophilia, intensely acidophilic granules. Secretes lysozyme, regulates gut bacteria 4) M cells: Overlie lymphatic nodules 5) enteroendocrine cells 6) Intermediate cells- stem cells

Question 32

Lamina propria in the mucosa of the small intestine is heavily infiltrated with what?

Answer 32

GALT

Question 33

Peyer's patches best seen where?

Answer 33

Ileum

Question 34

What the fuck is a peyer's patch

Answer 34

an aggregation of lymph nodes in the gut (ileum mostly)

Question 35

Brunner's glands are what?

Answer 35

Glands that secrete alkaline mucous, found in the submucosa of the DUODENUM, They hypertrophy in peptic ulcer dz

Question 36

Ileum distinguished by

Answer 36

Peyer's Patches!

Question 37

Easiest way to tell the small intestine from large?

Answer 37

Large has no villi, dawg Large also has more goblet cells for better lubrication.

Question 38

Function of the large intestines

Answer 38

absorption of water and electrolytes and elimination of solid waste.

Question 39

What separates the large intestine from teh small

Answer 39

ileocecal valve

Question 40

Epithelium in the Large intestine is basically the same as the small. It is ----- ------ in type but it has no ------ cells

Answer 40

simple columnar, paneth cells