Large Bowel & Drugs

Question 1

What connects the cecum to the distal ileum?

Answer 1

The ileocecal valve.

Question 2

What is the function of the ileocecal valve?

Answer 2

It regulates fluid flow from the small intestine into the colon and prevents coloileal reflux.

Question 3

Where does the appendix join the cecum?

Answer 3

Via the appendiceal orifice.

Question 4

What muscle structures define colonic haustra?

Answer 4

Circular muscle folds called plicae semilunares coli.

Question 5

What are the three taenia coli?

Answer 5

Epiploic, libera, and mesocolic longitudinal muscle bands.

Question 6

What covers the intraperitoneal portions of the colon?

Answer 6

A serosal layer.

Question 7

What covers the retroperitoneal portions of the colon?

Answer 7

An adventitial layer.

Question 8

What are appendices epiploicae?

Answer 8

Subserosal fat collections associated with the taenia coli.

Question 9

What is peristalsis?

Answer 9

Muscle contractions that squeeze fluid along the intestinal tract.

Question 10

What is segmentation?

Answer 10

Muscle contractions that break up material in the intestines.

Question 11

What is the only secretion in the colon?

Answer 11

Mucus.

Question 12

What stimulates colonic mucus secretion?

Answer 12

Parasympathetic nervous system.

Question 13

What are the three major mechanisms of sodium absorption in the colon?

Answer 13

Electroneutral NaCl, short-chain fatty acid/Na symporter, and sodium channels.

Question 14

What hormone enhances sodium absorption in the colon?

Answer 14

Aldosterone.

Question 15

What muscle holds the anorectal angle in the holding position?

Answer 15

Puborectalis muscle.

Question 16

What muscle contracts during the first stage of defecation?

Answer 16

Levator ani.

Question 17

What nerve is involved in the final voluntary stage of defecation?

Answer 17

Anal branch of the pudendal nerve.

Question 18

Which nerve plexus is initially activated during mass movements?

Answer 18

The myenteric plexus.

Question 19

What nerves are activated from the sacral spinal cord?

Answer 19

Pelvic nerves (parasympathetic).

Question 20

What initiates the final stage of defecation?

Answer 20

Somatic activation of the anal branch of the pudendal nerve.

Question 21

What percentage of faeces is water?

Answer 21

75%.

Question 22

What gives faeces its brown color?

Answer 22

Stercobilin.

Question 23

What causes the smell of faeces?

Answer 23

Indoles, skatole, mercaptans, and hydrogen sulfide.

Question 24

What types on the Bristol Stool Chart indicate constipation?

Answer 24

Type 1–2.

Question 25

What types indicate ideal stools?

Answer 25

Type 3–4.

Question 26

What types suggest diarrhea or urgency?

Answer 26

Type 5–7.

Question 27

What should be assessed in constipation diagnosis?

Answer 27

Alarm symptoms, acute vs chronic, and location of problem.

Question 28

What are common causes of diarrhea?

Answer 28

Infective, inflammatory, cancerous, metabolic, or endocrine causes.

Question 29

Name two main types of IBD.

Answer 29

Ulcerative colitis and Crohn’s disease.

Question 30

What percentage of Crohn's patients may need surgery?

Answer 30

60–75%.

Question 31

What is the treatment goal for UC?

Answer 31

Induce and maintain remission.

Question 32

What drug class is commonly used in mild-to-moderate UC?

Answer 32

Aminosalicylates.

Question 33

When is a rectal preparation used in UC?

Answer 33

For distal inflammation.

Question 34

Give an example of an aminosalicylate.

Answer 34

Sulfasalazine.

Question 35

What is the mechanism of sulfasalazine?

Answer 35

Anti-inflammatory, possibly inhibits TNF-α expression.

Question 36

What are alternatives to sulfasalazine for sulfa-allergic patients?

Answer 36

Balsalazide or Mesalazine.

Question 37

What organ can be affected by mesalazine?

Answer 37

Kidneys.

Question 38

What does methotrexate inhibit?

Answer 38

Purine synthesis and AICAR transformylase.

Question 39

Why can’t methotrexate be used in pregnancy?

Answer 39

It is teratogenic.

Question 40

What immune functions does methotrexate suppress?

Answer 40

T-cell activation and B-cell function.

Question 41

How does loperamide work?

Answer 41

Acts on mu-opioid receptors, decreases peristalsis, increases water absorption.

Question 42

Why should loperamide be avoided in acute ulcerative colitis?

Answer 42

Risk of megacolon and perforation.

Question 43

What is the active compound in Co-phenotrope?

Answer 43

Diphenoxylate with atropine.

Question 44

Why is atropine added to diphenoxylate?

Answer 44

To prevent abuse due to unpleasant effects in higher doses.

Question 45

What does kaolin do?

Answer 45

Adsorbs toxins and acts as a binding agent.

Question 46

What role does morphine play in anti-diarrhoeals?

Answer 46

Reduces peristalsis and increases stool firmness.

Question 47

Name a bulk-forming laxative.

Answer 47

Ispaghula husk.

Question 48

How do bulk-forming laxatives work?

Answer 48

Increase stool bulk, stimulating stretch receptors.

Question 49

What type of laxative is lactulose?

Answer 49

Osmotic laxative.

Question 50

Why is lactulose useful in liver failure?

Answer 50

Reduces ammonia levels.

Question 51

What are stimulant laxatives?

Answer 51

Senna, bisacodyl.

Question 52

How do stimulant laxatives work?

Answer 52

Stimulate myenteric plexus, increase bowel movement and secretion.

Question 53

What effect does fiber have on cholesterol?

Answer 53

Can moderately reduce cholesterol.

Question 54

What laxatives are hydrophilic and require water intake?

Answer 54

Ispaghula husk and methylcellulose.

Question 55

Why is lactulose contraindicated in heart failure?

Answer 55

Risk of fluid/electrolyte imbalance.

Question 56

Excessive use of laxatives lead to?

Answer 56

Melanosis Coli, Tolerance