Epithelia of small intestines

Question 1

What are the types of epithelia in the small intestines?

Answer 1

Enterocytes

Goblet cells

Enteroendocrine cells

Paneth cells

Stem cells

Question 2

What type of epithelial cell is most common in the small intestine?

Answer 2

Enterocytes

Question 3

What is the function of enterocytes in the small intestine?

Answer 3

Absorption

Question 4

What is the function of goblet cells in the small intestine?

Answer 4

Produce mucus

Question 5

What does mucus in the small intestine contain?

Answer 5

Bicarbonate ions

Question 6

What are the functions of mucus in the small intestine?

Answer 6

Physical barrier between epithelia and bacteria, to prevent bacterial infection

Lubricate gut, so contents can pass through more easily

Neutralises acidity of chyme from the stomach

Question 7

What is the structure of goblet cells?

Answer 7

Wider towards the top, contain mucus

Narrower towards the bottom, nucleus here

Question 8

What is the function of paneth cells in the small intestine?

Answer 8

Secrete antibacterial proteins

Question 9

What is the function of the antibacterial proteins in the small intestine?

Answer 9

Protect stem cells from damage by bacteria and their toxins

Question 10

What is the function of stem cells in the small intestine?

Answer 10

Divide every 2-4 days
migrate upwards
differentiate as they do so
to replace epithelial cells further up

Question 11

What are the types of enteroendocrine cells in the small intestine?

Answer 11

G cells

I cells

S cells

K cells

Question 12

What is the function of G cells?

Answer 12

Produce gastrin hormone

Question 13

What is the function of I cells?

Answer 13

Produce cholecystokinin hormone

Question 14

What is the function of S cells?

Answer 14

Produce secretin hormone

Question 15

What is the function of K cells?

Answer 15

Produce gastric inhibitory peptide hormone

Question 16

What is the structure of the inner surface of the small intestine?

Answer 16

Has villi

Has crypts

Question 17

What are villi?

Answer 17

Projections of mucosa of small intestine

into its lumen

Question 18

What are the epithelial cells on the surface of villi?

Answer 18

Enterocytes

Question 19

What are crypts?

Answer 19

Depressions of mucosa of small intestine to the muscularis mucosae
out of the lumen

Question 20

What are the epithelial cells on the surface of crypts?

Answer 20

Towards top of crypt are enterocytes
then goblet cells and enteroendocrine cells
then paneth cells
then stem cells towards bottom of crypt

Question 21

How is the small intestine adapted for absorption?

Answer 21

Its walls are folded into plicae circulares
plicae circulares are folded into villi
increases surface area

Question 22

What are plicae circulares?

Answer 22

Projections of submucosa of small intestine into its lumen

Question 23

How are enterocytes adapted for absorption?

Answer 23

Have microvilli on their apical domain

increases surface area

Question 24

What is the brush border of the small intestine?

Answer 24

Microvilli on apical domain of enterocytes

Question 25

What specific gland does the submucosa of the duodenum contain?

Answer 25

Brunner's glands

Question 26

What is the function of Brunner's glands?

Answer 26

Produce mucus

Question 27

Where do the ducts of the Brunner's glands in the duodenum drain into?

Answer 27

Crypts of duodenum

Question 28

How does the proportion of enterocytes change in the ileum?

Answer 28

Decreases

Question 29

How does the proportion of goblet cells change in the ileum?

Answer 29

Increases

Question 30

How does the proportion of Paneth cells change in the ileum?

Answer 30

Increases

Question 31

How does the amount of lymphoid tissue change in the ileum?

Answer 31

Increases

Question 32

What is the name of the lymphoid tissue in the ileum?

Answer 32

Peyer's patches

Question 33

Why does the ileum have more lymphoid tissue called Peyer's patches?

Answer 33

Because it is adjacent to the colon which contains many bacteria as part of the normal flora whereas the ileum is sterile so it has more lymphoid tissue to protect against infection

Question 34

How does the number of villi change in the ileum?

Answer 34

Decreases