large intestine structure and function

Question 1

What are the bands of longitudinal muscle that don’t go all away round the entire colon called

Answer 1

teniae coli

Question 2

What do the contractions of the teniae coli cause

Answer 2

Pouches called haustra

Question 3

What is the function of the crypts with the large number of goblet cells in the large intestine

Answer 3

Lubrication of the faeces

Question 4

What is the function of the colon

Answer 4

• can actively transport sodium from the lumen into the blood which can absorb water
• bacterial fermentation of undigested carbohydrate

Question 5

How does the urge to defaecate come about

Answer 5

Distension of the rectal wall produced by mass movement of faecal material into the rectum - activates mechanoreceptors which cause the defaecation reflex

Question 6

What controls the defaecation reflex

Answer 6

Pelvic splanchnic nerves - parasympathetic control

Question 7

What occurs in the defaecation reflex

Answer 7

Contraction of the rectum
Relaxation of internal anal sphincter
Contraction of the external anal sphincter
Increased peristalsis in the colon

Question 8

What are associated symptoms with constipation

Answer 8

Headaches
Nausea
loss of apetite
Abdominal distension

Question 9

How do enterotoxigenic bacteria cause diarrhoea

Answer 9

produce protein enterotoxins which turn up intestinal chloride secretion from crypt cells which increases water secretion as well and outworks the absorptive capacity of villi which results in watery diarrhoea

Question 10

What is the treatment of secretory diarrhoea

Answer 10

Give sodium and glucose
Rehydrate with oral rehydration therapy