Stomach and Esophagus

Question 1

How many layers of the esophagus? What are they from outermost to innermost?

Answer 1

4 layers: 
Serosa/adventitia
muscalaris externalis
submucosa
mucosa

Question 2

What are the three layers of the esophageal mucosa?

Answer 2

1. epithelium
2. lamina propria
3. muscularis mucosa

Question 3

What are the functions of the esophageal mucosa epithelium?

Answer 3

protective, absorptive, secretory –> may form glands –> often in folds/villi to increase SA

Question 4

What is the esophageal mucosa epithelium composed of?

Answer 4

nonkeratinized stratified squamous/columnar -> undergoes continuous renewal

Question 5

The upper third of the espohagus is composed of what muscle fibers?

Answer 5

skeletal muscle fibers, but undergo involuntary contractions

Question 6

The middle third of the espohagus is composed of what muscle fibers?

Answer 6

mixture of smooth and skeletal muscle

Question 7

The lower third of the espohagus is composed of what muscle fibers?

Answer 7

only smooth muscle

Question 8

What does the lamina propria of the esophageal mucosa have?

Answer 8

glands, lymphatic tissue, and macrophages

Question 9

What is the muscularis mucosa?

Answer 9

• outer layer of the esophageal mucosa

Question 10

What is the function of the muscularis mucosa

Answer 10

promotes movement of mucosa

Question 11

What is the muscularis mucosa composed of?

Answer 11

2 thin layers of smooth muscle

Question 12

what forms the submucosa?

Answer 12

dense connective tissue made from collagenous and elastic fibers
–thrown into folds

Question 13

What is another name for the submucosal plexus?

Answer 13

What is another name for the meissner’s corpuscle?

Question 14

Where would we find exocrine glands in the esophagus?

Answer 14

submucosa

Question 15

Where do we find meissner’s plexus?

Answer 15

at the junction between submucosa and inner circular layer of the muscularis externa

Question 16

Where do we find superficial glands? what else are the called?

Answer 16

superficial glands = cardiac glands

- found only in the lamina propria of the proximal and distal esophagus

Question 17

What do esophageal cardiac glands do?

Answer 17

provide a thin, highly viscous film of mucous to lubricate the esophagus

Question 18

What are the deeper glands of the esophagus?

Answer 18

aka esophageal glands = submucosal glands

• secrete acidic mucin
• located in the submucosa –> penetrate the muscularis mucosa to reach the lumen of the esophagus

Question 19

What are two layers of the muscularis externa?

Answer 19

inner circularly arranged layer
outer longitudianally arranged layer

they may be smooth or skeletal

Question 20

Where is the myenteric plexus located? another name for it?

Answer 20

aka auerbach’s plexus

-between the two layers of the muscularis mucosa

Question 21

What is serosa?

Answer 21

loose connective tissue that is covered by a simple squamous mesothelium

Question 22

What is adventitia?

Answer 22

connective tissue merged together that supports and protects

Question 23

Where is the esophagus covered by serosa? and adventitia?

Answer 23

esophagus in the peritoneal cavity is covered by serosa, the rest is covered by adventitia

Question 24

What is Barrett’s esophagus?

Answer 24

a response to injury –conversion from stratified squamous to simple columnar –> causes inflammation, possible cause of cancer, especially if too much acid reflux

Question 25

What are the three functions of the stomach?

Answer 25

1. reservoir of chyme 2. secretion of HCl 3. source of intrinsic factor 4. short term storage facility for food

Question 26

What are the four layers of the stomach?

Answer 26

mucosa, submucosa, muscularis externa, serosa/adventitia

Question 27

What are the four regions of the stomach?

Answer 27

cardia, fundus, body, pylorus

Question 28

What are rugae?

Answer 28

folds that increase the SA in the stomach - flatten as the stomach expands

Question 29

What type of epithelium cellular layer does the stomach have?

Answer 29

tall, simple columnar - replaced every 4-7 days

Question 30

What types of cells is line the stomach? what do they secrete?

Answer 30

mucus cells - secrete mucin, serves as a protective coating

Question 31

What are gastric glands?

Answer 31

invaginations of the surface epithelium - found in the body and fundus - largest and most numerous - make up 75% of the mucosa

Question 32

What are the three types of glands found in the stomach?

Answer 32

cardiac glands - found at the junction of the esophagus and stomach. secretions make up less than 10% of total mucosa gastric glands - in the fundus, pylorus, and body - secrete 75% of mucosa pyloric glands - 15% of mucosa secretions, found in the pylorus closest to duodenum of the stomach

Question 33

Where exactly do we find the gastric glands?

Answer 33

lamina propria of the mucosa

Question 34

What are the three parts of the gastric glands?

Answer 34

isthmus, neck, and body

Question 35

What types of cells are located in the neck region of the gastric/fundic glands?

Answer 35

mucous neck cells and parietal cells

Question 36

What types of cells are located in the body of the gastric/fundic glands?

Answer 36

upper part of the body: parietal and chief cells | lower part of the body: mostly chief cells

Question 37

What types of cells are mostly found in the cardiac and fundic glands?

Answer 37

mucus-secreting cells

Question 38

Tell me about the cardiac glands in the stomach.

Answer 38

- short branched tubular glands with short gastric pits - centered around the esophageal orifice - produce a mucus secretion that is 10% of the stomach's total secretion

Question 39

What are the three types of gastric glands?

Answer 39

cardiac, fundic, pyloric

Question 40

What are fundic glands?

Answer 40

= main gastric gland 99% of all stomach glands -main acid (HCl) and enzymatic producing gland

Question 41

What are the 6 different cell types located in the fundic glands?

Answer 41

1. surface epithelial cells 2. undifferentiated/stem cell 3. chief cells 4. parietal cells 5. mucous neck cells 6. enteroendocrine cells

Question 42

Describe the surface epithelial cells of the fundic glands.

Answer 42

tall columnar cells that produce a basic mucus for protection

Question 43

Describe the undifferentiated/stem cell of the fundic gland.

Answer 43

mitotically active cells that can replace cells lost via apoptosis - located in the isthmus and neck of the gland

Question 44

Describe the chief cells of the fundic gland.

Answer 44

localized at the base of the fundic gland and produce pepsinogen and lipase enzymes

Question 45

Describe the parietal cells of the fundic gland.

Answer 45

source of HCL and intrinsic factor -- located mainly in the neck - numerous mitochondria and cell membrane invaginations forming canaliculi from tubulovesicles

Question 46

Tell me about pyloric glands

Answer 46

- mucus producing glands with deep gastric pits --> similar to cardiac glands, but with deeper pits - some enteroendocrine cells present

Question 47

What are the three layers of the muscularis externa of the stomach?

Answer 47

- outer longitudinal - middle circular - inner oblique

Question 48

Where is the myenteric plexus located in the stomach wall?

Answer 48

between the middle circular and outer longitudinal layer of the muscularis externa

Question 49

What is the function of the muscularis externa of the stomach?

Answer 49

provides a means of peristalsis - mixing action of the stomach