3: Physiology and pharmacology of the large intestine

Question 1

Which reflex involves the opening of the ileocaecal valve to allow digested contents to pass through it?

Answer 1

Gastroileal reflex

Question 2

What triggers the gastroileal reflex?

Answer 2

Gastric distension

Question 3

Which valve is opened by the gastroileal reflex?

Answer 3

Ileocaecal valve

Question 4

What is the function of the ascending and transverse colon?

Answer 4

Fluid reabsorption

Bacterial fermentation

Question 5

What is the function of the descending and sigmoid colon?

Answer 5

Dessication and storage of faeces

Question 6

What triggers the gastrocolic reflex - strong peristalsis of muscles in the colon?

Answer 6

Meals

Question 7

What are haustra?

Answer 7

Pouches formed in the colon, increasing the surface area for fluid and electrolyte reabsorption

Question 8

What triggers the defecation reflex?

Answer 8

Rectal distension

Question 9

Which arm of the autonomic nervous system controls the involuntary relaxation of the internal anal sphincter?

Answer 9

Parasympathetic

Question 10

What triggers the parasympathetic relaxation of the internal anal sphincter?

Answer 10

Rectal distension by faecal matter

Question 11

While the initial relaxation of the internal anal sphincter is involuntary, what type of muscle controls the external anal sphincter?

Answer 11

Skeletal muscle

Question 12

What diseases are included under IBD?

Answer 12

Ulcerative colitis

Crohn’s disease

Question 13

Which class of drugs are used to maintain remission of UC?

Answer 13

Aminosalicylates

-alazines

Question 14

Name two aminosalicylates which are used to treat UC.

Answer 14

Sulfalazine

Mesalazine

Question 15

What drugs act as anti-inflammatories in both UC and Crohn’s?

Answer 15

Corticosteroids

Question 16

Name some corticosteroids used as an anti-inflammatory in Crohn’s and UC?

Answer 16

Prednisolone

Hydrocortisone

Beclometasone

Budesonide

Question 17

Corticosteroids have many side effects - what is the most important in terms of infection?

Answer 17

Immunodeficiency

Question 18

Name two“steroid-sparing” immunosuppressants used to treat Crohn’s and UC.

Answer 18

Azathioprine (Crohn’s/UC)

Methotrexate (Crohn’s)

Question 19

Which expensive drugs are sometimes used to inhibit TNFalpha activity in severe IBD?

Answer 19

Monoclonal antibodies

Question 20

Which prefix tells you that a drug is a monoclonal antibody?

Answer 20

-umab