Peristalsis

PERISTALSIS

Q. 1

The following bowel movement is not seen in normal individual:

 A

Peristalsis

 B

Peristaltic rush

 C

Segmentation contraction

 D

Migrating motor complex

Q. 1

The following bowel movement is not seen in normal individual:

 A

Peristalsis

 B

Peristaltic rush

 C

Segmentation contraction

 D

Migrating motor complex

Ans. B

Explanation:

Peristaltic rush is a very intense peristaltic wave, occurs when intestine is obstructed, thus not seen in normal individuals.

  • Peristalsis, segmental contraction, haustrations and migrating motor complex are all normal bowel movements.

Ref: Ganong’s, review of medical physiology, 22nd edition, Page 480, 482


Q. 2

Small intestinal peristalsis is controlled by :

 A

Myentric plexus

 B

Meissners plexus

 C

Vagus nerve

 D

Para sympathetic system

Q. 2

Small intestinal peristalsis is controlled by :

 A

Myentric plexus

 B

Meissners plexus

 C

Vagus nerve

 D

Para sympathetic system

Ans. A

Explanation:

A i.e. Myentric plexus

Myenteric (Auerbach’s) plexus is situated b/w and innervates outer longitudinal & middle circular muscular layers and is primarily concerned with motor controlQ. Submucosal (meissner’s) plexus situated between middle circular layer and mucosa is primarly concerned with control of intestinal secretionQ as it innervates glandular epithelium, intestinal endocrine cells & submucosal blood vessels.


Q. 3

Chyme is propelled forward in small intestine by

 A

Segmentation

 B

Haustrations

 C

Migratory motor complexes (MMC)

 D

Peristalsis

Q. 3

Chyme is propelled forward in small intestine by

 A

Segmentation

 B

Haustrations

 C

Migratory motor complexes (MMC)

 D

Peristalsis

Ans. D

Explanation:

D i.e. Peristalsis

Peristalsis propels the small intestinal content (chyme)Q toward the large intestine. It is a reflex response that is initiated when gut wall is stretched by contents of lumen. It occurs in all part of g.i tract from oesophagus to rectum propelling the content forward. It can be increased or decreased by autonomic input to gut but its occurrence is independent of extrinsic innervation. It is blocked only if the segment is reversed before it is sutured back (not by removed of intestine segment & resuturing in original position).


Q. 4

Antiperistalsis is seen in –

 A

Distal colon

 B

Jejunum

 C

Proximal Colon

 D

Ileum

Q. 4

Antiperistalsis is seen in –

 A

Distal colon

 B

Jejunum

 C

Proximal Colon

 D

Ileum

Ans. A

Explanation:

Ans. is ‘a’ i.e., distal colon 


Q. 5

Primary feature of small intestinal obstruction ‑

 A

Fever

 B

High peristalsis with colic

 C

Abdominal distension

 D

Empty rectum

Q. 5

Primary feature of small intestinal obstruction ‑

 A

Fever

 B

High peristalsis with colic

 C

Abdominal distension

 D

Empty rectum

Ans. B

Explanation:

Ans. is ‘b’ i.e., High peristalsis with colic 


Q. 6

In peristalsis following are involved except ‑

 A

NO

 B

Substance P

 C

Noradrenaline

 D

VIP

Q. 6

In peristalsis following are involved except ‑

 A

NO

 B

Substance P

 C

Noradrenaline

 D

VIP

Ans. C

Explanation:

Ans. is ‘c’ i.e., Noradrenaline

  • Peristalsis requires an active myenteric (Auerbach’s) plexus.
  • Local stretch by chyme releases serotonin, which activates myenteric plexus.
  • Cholinergic neurons of this plexus passing in a retrograde direction release substance P and acetylcholine, causing smooth muscle contraction.
  • Cholinergic neurons passing in an antegrade direction activate neurons that secrete NO, VIP, and ATP, produing relaxation ahead of the stimulus.

Q. 7

Which of the following is involved in peristalsis by causing relaxation ‑

 A

Substance P

 B

Acetylcholine

 C

VIP

 D

Norepinephrine

Q. 7

Which of the following is involved in peristalsis by causing relaxation ‑

 A

Substance P

 B

Acetylcholine

 C

VIP

 D

Norepinephrine

Ans. C

Explanation:

Ans. is ‘c’ i.e., VIP

In peristlasis :-

  1. Acetylcholine & substance P → Causing smooth muscle contraction.
  2. VIP, NO & ATP → Producing relaxation ahead of stimulus.


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