Gastrointestinal System Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What primarily determines the contraction rhythm of smooth muscle in the gastrointestinal tract?

Intracellular free calcium levels

Frequency of action potentials

Na+ influx in response to stimuli

Frequency of slow waves (correct)

In the absence of muscle contraction after drug X is applied, which step in the contraction-relaxation process is likely inhibited?

Activation of myosin light chain kinase

Opening of membrane calcium channels (correct)

Opening of sarcoplasmic reticulum calcium channels

Binding of ACh with membrane receptors

What is the role of the myenteric plexus in the gastrointestinal tract?

Regulates blood flow

Stimulates gut mucosa

Controls gastrointestinal secretion

Controls GIT movements (correct)

Which part of the sympathetic nervous system primarily inhibits gastrointestinal activity?

Thoracolumbar division Signup and view all the answers

What neurotransmitter is released to cause contraction of an intestinal muscle cell in response to intrinsic nerve stimulation?

Acetylcholine (ACh) Signup and view all the answers

What is the primary function of the submucosal plexus?

Regulate local blood flow Signup and view all the answers

Which statement accurately describes the effects of norepinephrine on the gastrointestinal tract?

Inhibits GIT activity Signup and view all the answers

Which of the following statements about slow waves is true?

Slow waves cause sodium influx without inducing contraction Signup and view all the answers

What is the primary function of the gastrocolic reflex?

Stimulating evacuation of the colon Signup and view all the answers

Which hormone is responsible for stimulating gastric acid secretion?

Gastrin Signup and view all the answers

What triggers the release of cholecystokinin (CCK)?

Presence of fats, acids, and proteins in the intestinal contents Signup and view all the answers

What is the role of the vagovagal reflex?

To control gastric motor and secretory activity Signup and view all the answers

What condition does the enterogastric reflex primarily address?

Inhibiting stomach motility and secretion Signup and view all the answers

Which structure primarily integrates the signals for the defecation reflex?

The spinal cord Signup and view all the answers

What role does gastrin play in the gastrointestinal system?

Promotes growth of the gastric mucosa and stimulates gastric acid secretion Signup and view all the answers

What effect does cholecystokinin (CCK) have on the gallbladder?

It stimulates gallbladder contraction to release bile Signup and view all the answers

What is the primary function of the longitudinal muscle layer in the gastrointestinal tract?

Extending the intestinal tract longitudinally Signup and view all the answers

Which type of electrical activity in the gastrointestinal smooth muscle is characterized by a gradual rise and fall in membrane potential?

Slow waves Signup and view all the answers

Which component of the gastrointestinal tract acts as electrical pacemakers for smooth muscle cells?

Interstitial cells of Cajal Signup and view all the answers

What are spike potentials triggered by in the gastrointestinal tract smooth muscle?

A rise in membrane potential above −40 mV Signup and view all the answers

What is the main role of gap junctions in gastrointestinal smooth muscle?

Facilitating electrical activity and contraction coordination Signup and view all the answers

What is the significance of the interstitial cells of Cajal's ion channels during slow wave generation?

They generate inward currents for slow waves Signup and view all the answers

What part of the gastrointestinal system secretes a viscous fluid?

Serosa (adventitia) Signup and view all the answers

Which of the following best describes the state of gastric smooth muscle contraction?

GIT contractions occur rhythmically Signup and view all the answers

What is the primary role of Cholecystokinin (CCK)?

Slows gastric emptying for fat digestion Signup and view all the answers

Which condition stimulates the secretion of Secretin?

Fats and acid in the duodenum Signup and view all the answers

What effect does Gastric Inhibitory Peptide (GIP) have on gastric acid secretion?

Inhibits gastric acid secretion Signup and view all the answers

Which hormone is primarily responsible for increasing gastrointestinal motility during fasting?

Motilin Signup and view all the answers

What is the mechanism of action of peristalsis in the gastrointestinal tract?

A contractile ring forming and moving forward Signup and view all the answers

What is the primary site of secretion for Gastric Inhibitory Peptide (GIP)?

Duodenum and Jejunum Signup and view all the answers

Which hormone would most likely be injected to initiate intense contractions of the proximal duodenum?

Motilin Signup and view all the answers

What type of digestive movement is characterized by moving food forward along the digestive tract?

Propulsive movements Signup and view all the answers

What is primarily responsible for the movement of contents towards the anus in the gastrointestinal tract?

Peristaltic waves Signup and view all the answers

Which substances are released from the intestinal mucosa to increase blood flow during gastrointestinal activity?

Cholecystokinin and vasoactive intestinal peptide Signup and view all the answers

Which of the following correctly indicates a potential cause of chronic diarrhea?

Bacterial or viral infections Signup and view all the answers

What impact does atropine have on the gastrointestinal system?

Paralyzes cholinergic nerve endings Signup and view all the answers

What is the primary function of reticuloendothelial cells in the liver?

Remove bacteria and harmful agents Signup and view all the answers

Which disorder is specifically characterized by reverse peristalsis?

Vomiting Signup and view all the answers

What condition can result from chronic diarrhea due to loss of bicarbonate?

Metabolic acidosis Signup and view all the answers

How do segmentation contractions contribute to digestion?

By mixing and breaking up food contents Signup and view all the answers

Study Notes

Gastrointestinal Smooth Muscle Contraction

Pacemaker activity of interstitial cells of Cajal is the primary determinant of smooth muscle contraction rhythm in the gastrointestinal tract.
Drug X inhibiting muscle contraction likely disrupts the calcium release step in the contraction-relaxation process.
Myenteric plexus controls motility within the gastrointestinal tract.
Sympathetic nervous system's postganglionic fibers inhibit gastrointestinal activity.
Acetylcholine is the neurotransmitter responsible for intestinal muscle cell contraction in response to intrinsic nerve stimulation.

Gastrointestinal Regulation

Submucosal plexus regulates gastrointestinal secretions.
Norepinephrine inhibits gastrointestinal motility.
Slow waves are slow, rhythmic fluctuations in membrane potential of gastrointestinal smooth muscle and do not cause muscle contraction.
Gastrocolic reflex triggers mass movement in the colon following a meal in the stomach.
Gastrin stimulates gastric acid secretion.

Gastrointestinal Hormones and Reflexes

Cholecystokinin (CCK) release is triggered by presence of fatty acids and amino acids in the duodenum.
Vagovagal reflex involves sensory and motor fibers of the vagus nerve, regulates gastric motility and secretion.
Enterogastric reflex primarily addresses the inhibition of gastric emptying when the duodenum is full.
Defecation reflex integration occurs primarily in the spinal cord.
Gastrin promotes gastric motility and secretion.
Cholecystokinin (CCK) stimulates gallbladder contraction and release of bile.

Gastrointestinal Structure and Function

Longitudinal muscle layer is primarily responsible for shortening and propelling intestinal contents.
Slow waves are characterized by a gradual rise and fall in membrane potential of gastrointestinal smooth muscle.
Interstitial cells of Cajal act as electrical pacemakers for smooth muscle cells in the gastrointestinal tract.
Spike potentials are triggered by depolarization of the membrane beyond a threshold in the smooth muscle of the gastrointestinal tract.

Gastrointestinal Cell Communication and Function

Gap junctions in gastrointestinal smooth muscle facilitate communication and synchronous contraction of muscle cells.
Interstitial cells of Cajal's ion channels play a key role in slow wave generation.
Stomach secretes mucus , which provides protection and lubrication.
Gastric smooth muscle generally exists in a tonic state of contraction.
Cholecystokinin (CCK) primarily regulates gallbladder emptying and pancreatic enzyme secretion.
Secretin is stimulated by presence of acidic chyme in the duodenum.
Gastric Inhibitory Peptide (GIP) inhibits gastric acid secretion.
Motilin increases gastrointestinal motility during fasting.
Peristalsis uses coordinated contractions and relaxations of the gastrointestinal smooth muscle to move food forward.
Duodenum is the primary site of secretion for Gastric Inhibitory Peptide (GIP).
Cholecystokinin (CCK) could be injected to initiate intense contractions in the proximal duodenum.
Peristalsis is a type of digestive movement that propels food forward.
Intestinal smooth muscle contractions are responsible for the movement of contents towards the anus in the gastrointestinal tract.
Intestinal mucosa releases vasodilators to increase blood flow during gastrointestinal activity.
Chronic diarrhea could potentially be caused by malabsorption, infection or bowel disorders.
Atropine inhibits acetylcholine's effect, decreasing gastrointestinal motility.
Reticuloendothelial cells in the liver are involved in phagocytosis and immune response.
Reverse peristalsis is characteristic of vomiting as it moves stomach contents upward.
Chronic diarrhea can lead to metabolic alkalosis due to loss of bicarbonate.
Segmentation contractions mix chyme with digestive juices for efficient digestion.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the structure and functions of the gastrointestinal system in this quiz. Learn about the GIT wall layers, smooth muscle functions, and electrical activity in digestion. Test your knowledge on how these components work together for nutrient absorption.