Vomiting, Motility Of The Small And Large Intestine, And Defecation

Question 1

Emetics

Answer 1

Chemicals that trigger vomiting

Trigger zone in fourth ventricle, reached by almost all blood borne agents

Question 2

Hirshsprung’s disease

Answer 2

Absence of ENS in segment of colon and remains constricted due to tonic effect provided by parasympathetics

Question 3

Diverticulosis

Answer 3

Development of small pouches within the colon

Material gets into pouches and gets infected

Question 4

Physiological conditions of colonic motility

Diarrhea

Answer 4

Diarrhea: rapid movement of material through colon, complete water absorption does not occur
Enteritis: bacterial, viral, or protozoan infection that irritates mucosa and increases secretions and motility of colon
Ulcerative colitis: immune allergic reaction, colon inflamed and ulcerated, increases colonic secretions and reduces absorption and induces frequent mass movements

Question 5

Physiological conditions of colonic motility

Constipation

Answer 5

Constipation: feces remaining in large bowel too long, due to decreased GI motility or blockage
Irregular bowel habits: continuous voluntary suppression of defecation tend to weaken defecation reflex
Overuse of laxatives and spasms of sigmoid colon: weakens defecation reflex
Opioids: act on receptors of ENS which decrease frequency of mass movements and increase anal sphincter tone, increase fecal transit time

Question 6

Gastroileal reflex

Answer 6

Gastric activity increases ideal motility

Gastrin

Question 7

Ileogastric reflex

Answer 7

Distension of ileum inhibits gastric motility

Question 8

Intestinointestinal reflex

Answer 8

Over distension of any part relaxes rest

Question 9

Control of colonic contractions

Answer 9

Stimulate: Ach and substance P
Inhibit: VIP and NO

Question 10

Colonocolonic reflex

Answer 10

Distension of one part of colon relaxes rest

Question 11

Gastrocolic reflex

Answer 11

Increased motility and frequency of mass movements as food enters stomach