Peristaltic Rush: Small Intestine Peristalsis Quiz and Flashcards

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Questions and Answers

What type of movement occurs in the small intestine when a portion becomes distended with chyme?

Mixing movements

Migratory motor complex

Segmentation contractions (correct)

Peristalsis

What is the purpose of segmentation contractions in the small intestine?

Creating peristalsis

Generating migratory motor complex

Mixing food with secretions (correct)

Propulsion of chyme

How often do segmentation contractions chop the chyme in the small intestine?

Five times per minute

Two to three times per minute (correct)

Once every minute

Once every 30 seconds

During segmentation contractions in the small intestine, what is the appearance of the intestine?

Chain of sausages Signup and view all the answers

Which movement in the small intestine involves localized concentric contractions at intervals along the intestine?

Segmentation contractions Signup and view all the answers

What is the primary function of mixing movements in the small intestine?

Chopping chyme into smaller pieces Signup and view all the answers

What determines the maximum frequency of segmentation contractions in the small intestine?

The frequency of electrical slow waves in the intestinal wall Signup and view all the answers

At what rate does chyme move through the small intestine on average?

1 cm/min Signup and view all the answers

What primarily provides background excitation for segmentation contractions?

Myenteric nerve plexus Signup and view all the answers

What is the maximum frequency of segmentation contractions in the terminal ileum under normal conditions?

8 to 9 contractions per minute Signup and view all the answers

What is the primary function of peristaltic movements in the small intestine?

Propel chyme through the intestine Signup and view all the answers

How long does it typically take for chyme to travel from the pylorus to the ileocecal valve?

3 to 5 hours Signup and view all the answers

What is the main trigger for the occurrence of the peristaltic rush in the small intestine?

Irritation of intestinal mucosa Signup and view all the answers

What initiates the powerful peristaltic contractions during the peristaltic rush?

Intrinsic stimulation of the myenteric plexus reflexes Signup and view all the answers

What is the function of the ileocecal valve and sphincter?

Slowing emptying of ileal contents into the cecum Signup and view all the answers

Which part of the small intestine is relieved from irritative chyme during a peristaltic rush?

Ileum Signup and view all the answers

What intensifies peristalsis in the ileum and relaxes the ileocecal sphincter after a meal?

Gastroileal reflex Signup and view all the answers

What causes the ileocecal valve to close and prevent cecal contents from moving backward?

Pressure build-up in the cecum Signup and view all the answers

What controls the degree of contraction of the ileocecal sphincter and the intensity of peristalsis in the terminal ileum?

Reflexes from the cecum Signup and view all the answers

How does irritation in the cecum affect the movement of chyme into the cecum?

Delays the movement Signup and view all the answers

What happens to the ileocecal sphincter when the cecum is distended?

It contracts more Signup and view all the answers

What occurs during migratory motor complex movements?

Repeated waves of peristaltic activity Signup and view all the answers

What starts slightly farther down the small intestine during migratory motor complex movements?

Peristaltic activity Signup and view all the answers

What is the effect of an inflamed appendix on the ileocecal sphincter and ileum?

Intense spasm of the ileocecal sphincter and partial paralysis of the ileum Signup and view all the answers

What initiates the peristaltic activity of the small intestine after a meal?

Entry of chyme into the duodenum Signup and view all the answers

Which neurotransmitter mediates the increase in motility in the small intestine through the gastroenteric reflex?

Acetylcholine Signup and view all the answers

What effect do gastrin, CCK, and serotonin have on intestinal motility?

Enhance small intestinal motility Signup and view all the answers

Which hormone inhibits small intestinal motility?

Secretin Signup and view all the answers

What happens when chyme reaches the ileocecal valve?

It intensifies peristalsis in the ileum Signup and view all the answers

Study Notes

Small Intestine Motility

When a portion of the small intestine becomes distended with chyme, a type of movement called segmentation contractions occurs.
The purpose of segmentation contractions is to mix chyme with digestive enzymes and increase the surface area for absorption.
Segmentation contractions chop the chyme into smaller particles at a rate of about 12-15 times per minute.
During segmentation contractions, the intestine appears beaded or segmented in appearance.
Mixing movements in the small intestine involve localized concentric contractions at intervals along the intestine, which aids in mixing chyme with digestive enzymes.
The primary function of mixing movements is to increase the surface area for absorption.
The maximum frequency of segmentation contractions is determined by the electrical slow wave activity of the intestine.
On average, chyme moves through the small intestine at a rate of 1-2 mm/sec.

Peristaltic Movements

Peristaltic movements involve a wave-like contraction that helps propel chyme through the small intestine.
The primary function of peristaltic movements is to propel chyme through the small intestine towards the large intestine.
Peristaltic contractions are initiated by the gastroenteric reflex, which is mediated by the neurotransmitter acetylcholine.
It typically takes 3-5 hours for chyme to travel from the pylorus to the ileocecal valve.
The main trigger for the occurrence of the peristaltic rush is the presence of irritative substances in the small intestine.

Ileocecal Valve and Sphincter

The ileocecal valve and sphincter prevent backflow of cecal contents into the small intestine.
The ileocecal valve closes and prevents backflow when the cecum is distended.
The degree of contraction of the ileocecal sphincter and the intensity of peristalsis in the terminal ileum are controlled by the enteric nervous system.

Migratory Motor Complex (MMC) Movements

MMM movements occur during the interdigestive period and help clear the small intestine of residual particles.
MMM movements start in the stomach and progress downward through the small intestine, occurring every 90-120 minutes.
During MMM movements, the ileocecal sphincter relaxes, allowing residual particles to enter the cecum.

Other Factors Affecting Motility

Irritation in the cecum causes a decrease in motility in the terminal ileum.
An inflamed appendix causes a decrease in motility in the terminal ileum and an increase in tone of the ileocecal sphincter.
Gastrin, CCK, and serotonin increase motility in the small intestine through the gastroenteric reflex.
Secretin inhibits small intestinal motility.

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Description

Learn about peristalsis in the small intestine, the process by which food is moved through the digestive tract. Understand how distension of the intestine triggers reflex contractions and relaxations to propel food forward for absorption.

Peristalsis in the Small Intestine

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