Histology

Question 1

What are the three layers of the mucosa?

Answer 1

Surface epithelium
Lamina propria
Muscularis mucosae (smooth muscle)

Question 2

In what layers are the nerves?

Answer 2

Submucosal nerve plexus is in submucosa layer

Myenteric plexus is between the two smooth muscle layers

Question 3

What are four other layers of hollow visceral organs?

Answer 3

Submucosa–>Inner circular muscle layer–>outer longitudinal muscle layer–>adventitia

Question 4

Is there any absorption or secretion in the esophagus?

Answer 4

No absorption, little secretion

Question 5

What is special about the muscle in the esophagus

Answer 5

It’s super thick

Question 6

What types of glands are in the esophagus? How common are they

Answer 6

There are salivary-type glands, but they are rare

Question 7

What are the three different regions of the stomach?

Answer 7

cardia, corpus, antrum

Question 8

Describe the components of a fovea:

Answer 8

surface epithelium with gastric pits leading to gastric gland
In the gland, there are mucous neck cells, gastric glands, chief cells and enteroendocrine cells

Question 9

What are the pink cells? What are the blue cells?

Answer 9

Pink: parietal cells producing acid (think pH)
Blue: chief cells producing pepsinogen

Question 10

How is acid production stimulated in the corpus of the stomach?

Answer 10

Histamine and gastrin stimulate acid production by parietal cells

Question 11

How is gastrin secreted?

Answer 11

Gastrin is secreted by antral neuroendocrine cells into the blood steam and acts directly on parietal cells

Question 12

How is histamine secreted?

Answer 12

Gastrin from antral neuoendocrine cells stimulates enterchromaffin-like cells in the corpus to secrete histamine

Question 13

What are the various levels of increased surface area in the SI?

Answer 13

Plica (folds)–>Villi–>microvilli

Question 14

At what point do we start seeing mucosa-associated lymphoid tissue?

Answer 14

Small intestine

Question 15

What are lacteals?

Answer 15

lymph vessels in lamina propr. that absorb dietary lipids into the lymphatic system

Question 16

What are paneth cells?

Answer 16

Cells that provide phagocytosis and intracellular digestion of intestinal microorganisms

Question 17

What are the slight pink glands in the small intestine? What are their function?

Answer 17

Brunner glands produce a mucus-rich alkaline secretion

Protection from gastric acid, alkalization to allow digestive enzymes to work

Question 18

What substances are absorbed and secreted by the colon?

Answer 18

Absorption: water, sodium, chloride
Secretion: bicarbonate and mucus

Question 19

How is mucus secreted in the colon? What is its function?

Answer 19

Globlet cells secrete mucus in response to tactile stimuli from luminal contents–
Mucus protects the epithelium and binds ingested material to form feces

Question 20

Where are the lymphatic vessels in the colon?

Answer 20

In the submucosa layer– rarely metastasize

Question 21

Are there villi in the colon?

Answer 21

No, but there are crypts

Question 22

Rectum: does it have villi or crypts?

Answer 22

Crypts

Question 23

What are hemorrhoids?

Answer 23

Anal vein prolapse due to raised intra-abdominal pressure
Enlarging uterus increases pressure
Poor venous drainage
Straining at stool