Histology of the Esophagus and Stomach

Question 1

4 layers of the GI tract from lumen outwards

Answer 1

Mucosa
Submucosa
Muscularis externa
Serosa/adventitia

Question 2

3 components of mucosal layer

Answer 2

Lining epithelium.
Lamina propria (loose CT)
Muscularis mucosae (controls mucosa/mucosal glands)

Question 3

Submucosal layer (2)

Answer 3

Dense irregular CT w/ neurovasculature and lymphatics.

Glands present in esophagus and duodenum.

Question 4

2 layers of muscularis externa and their functions

Answer 4

Circular layer constricts lumen.

Longitudinal layer shortens tube.

Question 5

Where do the neurovascular plexuses reside in muscularis externa?

Answer 5

Between the 2 layers of muscle.

Question 6

When does mesothelium cover the adventitia, resulting in the serosa layer?

Answer 6

When the tube is suspended by a mesentery/peritoneal fold.

Question 7

Extrinsic component of GI innervation

Intrinsic component of GI innervation

Answer 7

Ext - ANS.

Int - Enteric NS

Question 8

What nerves control the GI?

Answer 8

Vagus n. to the splenic flexure.

Pelvic splanchnic ns. after splenic flexure.

Question 9

Which fibers are considered “intermural”?

Answer 9

Ganglia and postsynaptic fibers.

Question 10

Sympathetics come from branches of:

Answer 10

Greater, lesser, least and lumbar splanchnic ns.

Question 11

How do postsynaptic ns. travel to organs?

Answer 11

Travel via blood vessels via peri-arterial plexuses

Question 12

2 interneurons in enteric NS?

Answer 12

Submucosal plexus of Meissner

Myenteric plexus of Auerbach

Question 13

Enteric NS regulates:

Answer 13

Peristalsis of muscularis externa and movements of muscularis mucosae.
Secretory activity of mucosal/submucosal glands.

Question 14

Which nerves increase motility?

Answer 14

Preganglionic axons of parasympathetics.

Question 15

Which nerves decrease motility?

Answer 15

Postganglionic axons of sympathetics.

Question 16

Where does the esophagus have adventitia? Serosa?

Answer 16

Adventitia - thoracic esophagus

Serosa - inferior to diaphragm

Question 17

Cardiac esophageal glands

Answer 17

Reside in LP of terminal esophagus.

Question 18

Epithelium in mucosa of esophagus

Answer 18

Nonkeratinized stratified squamous

Question 19

Where is the muscularis mucosae present in the esophagus?

Answer 19

Only in lower segment

Question 20

Submucosal venous plexuses

Answer 20

In submucosa of esophagus.

Drains into systemic and portal venous system.

Question 21

Esophageal varices

Answer 21

Created by increased pressure.

They are dilations of the submucosal venous sinuses.

Question 22

Muscularis externa of:
Upper 1/3 of eso
Middle 1/3 of eso
Lower 1/3 of eso

Answer 22

Upper 1/3 of eso - skeletal muscle
Middle 1/3 of eso - skeletal and SM
Lower 1/3 of eso - SM

Question 23

What is the epithelial transition from esophagus to stomach?

Answer 23

NKSS to simple columnar.

Question 24

2 sphincters of esophagus and their functions

Answer 24

Upper esophageal sphincter (UES) - anatomical, swallowing reflex.
Lower esophageal sphincter (LES) - funcional, prevents reflux of gastric contents.

Question 25

Barrett's esophagus is caused by:

Answer 25

Chronic GERD causing the NKSS in transition zone to become mucous secreting/glandular.

Question 26

Orad area of stomach

Answer 26

Fundus and upper part of body of stomach. | Relaxes during swallowing.

Question 27

Caudad area of stomach

Answer 27

Lower part of body and antrum. | Participates in regulation of gastric emptying.

Question 28

Mucosa, Submucosa, Muscularis externa of Stomach

Answer 28

Mucosa - simple columnar epi, many glands, reticular/collagen predominate. Submucosa - dense irregular CT, Meissner's plexus ME - has 3 layers (oblique)

Question 29

Pyloric sphincter

Answer 29

Thickening of circular muscle in the pyloric region.

Question 30

Does the stomach have serosa or adventitia?

Answer 30

Serosa, containg loose CT w/ BVs

Question 31

Fundic/gastric glands is present:

Answer 31

Throughout gastric mucosa except for region occupied by cardiac and pyloric glands.

Question 32

How far do the fundic/gastric glands extend?

Answer 32

Into the muscularis mucosae.

Question 33

3 regions of fundic/gastric glands

Answer 33

Isthmus Neck Fundus

Question 34

Isthmus contains which kinds of cells (2)

Answer 34

Dividing cells | Undifferentiated cells

Question 35

Neck contains which kinds of cells (3)

Answer 35

Mucous neck cells Parietal cells Enteroendocrine cells

Question 36

Fundus contains which kinds of cells (3)

Answer 36

Chief cells Enteroendocrine cells Few parietal cells

Question 37

Chief cells

Answer 37

``` Lots of RER. Secretes pepsinogen (digests proteins) ```

Question 38

Parietal cells

Answer 38

Produce HCl and intrinsic factor (glycoprotein that binds vit B12)

Question 39

3 distinct features of parietal cells

Answer 39

Increased mitocondria Intracellular canaliculus H+, K+ dependent ATPase-rich tubulovesicular system

Question 40

Closed enteroendocrine cells

Answer 40

Small cells that rest on basal lamina and don't always reach lumen.

Question 41

Open enteroendocrine cells

Answer 41

Have thin cytoplasmic extension w/ microvilli are are exposed to lumen. Contain chemoreceptors.

Question 42

Gastrin is produced by: | Stimulates:

Answer 42

G cells in pyloric antrum. | Production of HCl by parietal cells.

Question 43

Somatostatin is produced by: | Inhibits:

Answer 43

D cells. | Inhibits gastrin.

Question 44

Ghrelin is produced by: Function: What happens to ghrelin levels while fasting?

Answer 44

Gastric fundus. Stimulates GH secretion. Increases (triggers hunger)

Question 45

Cardiac glands

Answer 45

Tubular and coiled, slightly branched. Opening continuous w/ gastric pits. Lined w/ mucus-secreting cells.

Question 46

Pyloric glands

Answer 46

Branched, coiled, tubular between fundus and pylorus. Large and pale. Lined by mucus-secreting cells.