Small Intestine Structure and Function

Question 1

What are the functions of the Duodenum?

Answer 1

Gastric acid neutralisation, digestion and iron absorption

Question 2

What is the function of the Jejunum?

Answer 2

Nutrient absorption

Question 3

What is the function of the Ileum?

Answer 3

NaCl/H2O absorption and chime deydration

Question 4

What is the function of the villus cell?

Answer 4

They absorb nutrients

Question 5

What is the function of the crypt cell?

Answer 5

They secrete Cl and water

Question 6

How much water does the small intestine secrete per day?

Answer 6

Approx. 1.5l per day

Question 7

How is water secreted in the small intestine?

Answer 7

Passively (osmotically) as a consequence of active secretion of chloride into intestinal lumen

Question 8

What are the functions of water in the small intestine?

Answer 8

Maintaining luminal contents in liquid state
Promotes mixing of nutrients with digestive enzymes
Aids nutrients with digesting enzymes
Dilute and washes away potentially injurious substances

Question 9

What are the two types of intestinal movement?

Answer 9

Segmentation and peristalsis

Question 10

What is the function of segmentation in the small intestine?

Answer 10

Moves the chyme up and down which mixes the contents with digestive enzymes

Question 11

What generates segmentation?

Answer 11

Depolarisation generated by pacemaker cell in the longitudinal muscle layer (Intestinal basic electrical rhythm produces oscillations in the membrane potential)

Question 12

What is the migrating motility complex?

Answer 12

A pattern of peristaltic activity travelling down the small intestine

Question 13

What are the functions of the MMC?

Answer 13

To move undigested material into the large intestine and limits bacterial colonisation of the small intestine

Question 14

What hormone is involved in the initiation of MMC?

Answer 14

Motilin

Question 15

What is the law of the intestine?

Answer 15

If the intestinal smooth muscle is distended:
Muscle on oral side of the bolus contracts
Muscle on anal side of bolus relaxes
Bolus is moved into area of relaxation towards colon

Question 16

What is the gastroileal reflex?

Answer 16

Gastric Emptying causes:
Opening of ileocaecal valve (sphincter)
Entry of chyme into the large intestine
Distension of colon
Reflex contraction of ileocaecal sphincter