Intestines

Question 1

What is the length of the jejunum and ileum?

Answer 1

Jejunum is 2.5 m and ileum is 3.5 m

Question 2

What features increase the surface area in the small intestines?

Answer 2

Plicae circulares (valves of kerckring), villi/crypts, and microvilli (with brush border)

Question 3

Do crypts of intestinal villi cross the muscularis mucosae?

Answer 3

No

Question 4

What type of epithelium is present in the small intestine?

Answer 4

Simple columnar

Question 5

The simple columnar epithelium of small intestines is populated by what 5 types of cells?

Answer 5

1. Enterocytes 2. Goblet cells
2. EEC/APUD cells 4. Paneth cells
3. Stem cells

Question 6

What provides protection from invasive microorganisms in the small intestines?

Answer 6

1. sIgA 2. tight junctions between enterocytes 3. GALT

Question 7

Where are goblet cells highest in frequency: duodenum, jejunum, ileum, large intestine?

Answer 7

Goblet cells increase in frequency toward the large intestine.

Question 8

What type of stem cells are present in the small intestine?

Answer 8

Pleuripotential cells

Question 9

Where are APUD cells found in the small intestines?

Answer 9

In crypts

Question 10

Where is sertonin secreted?

Answer 10

EC cells in the small intestine and fundus of the stomach

Question 11

What cells secrete CCK?

Answer 11

I cells in the small intestines

Question 12

What cells secrete secretin?

Answer 12

S cells in the small intestines

Question 13

What is the function of secretin?

Answer 13

stimulates pancreatic and biliary bicarbonate and water secretion

Question 14

What is the function of somatostatin?

Answer 14

Inhibits parietal and chief cell secretion

Question 15

What is the function of chief cells?

Answer 15

secrete pepsinogen

Question 16

What layer of the small intestine contains smooth muscle cells?

Answer 16

Lamina propria

Question 17

Where are Brunner’s glands found?

Answer 17

submucosa of the duodenum

Question 18

Where are Peyer’s patches found?

Answer 18

submucosa of the ileum

Question 19

What is the function of Brunner’s glands?

Answer 19

secretes a clear alkaline mucin into neck of crypts (protection against acid chyme)

Question 20

Define Peyer’s patches.

Answer 20

GALT, covered by M cells, important in immune response

Question 21

True or False: M cells are APC’s

Answer 21

FALSE. They are NOT APC’s.

Question 22

What is the difference between the mucosa of the large intestine versis the mucosa of the small intestine?

Answer 22

The mucosa of the large intestine has no villi and no plicae circularis. Crypts/glands are still present.

Question 23

What is the difference between the mucsularis externa of the large intestin and the muscularis externa of the small intestine?

Answer 23

The outer longitudinal muscle layer of the large intestine is formed by 3 longitudinal stripes called TANEA COLI

Question 24

How are the layers of the colon different from the rectum?

Answer 24

The rectum lacs tanea coli

Question 25

What is the embryonic origin of the proximal 1/2 of the anal canal?

Answer 25

Endoderm

Question 26

What is the embryonic origin of the distal 1/2 of the anal canal?

Answer 26

Ectoderm

Question 27

What is the dividing point between the upper and lower anal canal?

Answer 27

Pectinate line

Question 28

What type of epithelium is found above the pectinate line?

Answer 28

Simple columnar

Question 29

What type of epithelium is found below the pectinate line?

Answer 29

Non-keratinized strafied squamous

Question 30

Where is the most likely place to get hemorrhoids?

Answer 30

Lamina propria at the pectinate line contains large plexus of veins.

Question 31

Where are anal columns located?

Answer 31

Upper anal canal

Question 32

What is the blood supply of the anal canal above the pectinate line?

Answer 32

Superior rectal artery (branch of the IMA)

Question 33

What is the blood supply of the anal canal below the pectinate line?

Answer 33

Inferior rectal artery (branch of the internal pudendal artery)

Question 34

What is the internal anal sphincter composed of?

Answer 34

thickened inner circular layer of muscularis externa