L40: Small Intestine

Question 1

What are the three components of the small intestine?

Answer 1

• Duodenum;
• Jejunum;
• Ileum.

Question 2

What are the primary functions of the s. intestine?

Answer 2

Digestion and absorption

Question 3

What structure supports the s. intestine in place?

Answer 3

Parietal peritoneum

Question 4

What structure gives rise to the lubricating layer of the peritoneum?

Answer 4

Mesothelium (serous membrane) comprised of mesothelial cells

Question 5

What is the mesentery?

Answer 5

A fold of membrane that attaches the intestine to the abdominal wall and holds it in place

Question 6

What is the omentum?

Answer 6

A double fold of peritoneum connecting the stomach with other organs

Question 7

Where are Brunner’s glands and what are their purpose?

Answer 7

In the duodenum, produce an alkaline secretion to neutralise the acid from stomach

Question 8

Where is the sphincter of Oddi and what is its purpose?

Answer 8

Located in the duodenum (major duodenal papilla), controls the amount of bile and pancreatic juice secreted into the duodenum

Question 9

What is CCK and what does it stimulate?

Answer 9

• A hormone, chole-cysto-kinin;
• Released by the duodenum in response to fat and protein;
• Stimulates contraction of the gall bladder;
• Relaxation of the sphincter of Oddi.

Question 10

What supplies blood to the duodenum?

Answer 10

• Coeliac trunk;

- Superior mesenteric artery.

Question 11

What drains blood from the duodenum?

Answer 11

Inferior vena cava

Question 12

Where does the duodenum end?

Answer 12

Duodenojejunal junction

Question 13

Where does digestion primarily occur in the s. intestine?

Answer 13

Duodenum

Question 14

What digestive processes occur in the jejunum?

Answer 14

Digestion (and absorption)

Question 15

What digestive processes occur in the ileum?

Answer 15

Absorption

Question 16

How is the jejunum specialised to continue digestion?

Answer 16

Brush border enzymes

Question 17

How is the s. intestine specialised to carry out its functions?

Answer 17

Microvilli across the entire surface area of the intestinal tract, finger-like projections which increase the surface area 5000x

Question 18

What are Peyer’s patches?

Answer 18

• Found in the ileum;

- Collections of inflammatory tissue which monitor snd prevent unwanted bacterial activity of the gut.

Question 19

What are enterocytes?

Answer 19

• Simple columnar epithelial cells;
• Microvilli (brush border)
• Brush border enzymes;
• Carrier proteins.

Question 20

How is chyme moved along the gut?

Answer 20

• CILO;
• Circular: local breakdown of food through constriction;
• Outer: passes food along through shortening.

Question 21

What is Meckel’s diverticulum?

Answer 21

• An out-pouching of the ileum;
• Rule of 2’s;
• 2% of pop., 2+, 2ft from valve.

Question 22

What are intestinal crypts (of Leiberkuhn)?

Answer 22

Intestinal glands found along the epithelium lining (invaginations), secrete intestinal juice