overview of digestive system

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Which type of smooth muscle cells in the GIT are responsible for generating slow wave potentials?

Pacemaker cells

Autorhythmic cells (correct)

Contractile cells

Interstial cells

What is the primary function of autorhythmic cells in the GIT?

To regulate the frequency of spike potentials

To generate action potentials

To generate slow wave potentials (correct)

To contract the smooth muscle

What is the effect of an increase in the frequency of spike potentials on the amplitude of GIT smooth muscle contraction?

It decreases the amplitude of contraction

It has no effect on the amplitude of contraction

It increases the amplitude of contraction (correct)

It varies depending on the location in the GIT

What is the effect of acetylcholine on the GIT motility?

It increases the frequency of generation of spike potentials (D) Signup and view all the answers

What is the role of Ca2+ channels in the slow wave potentials?

They cause the depolarizing phase of the slow wave (C) Signup and view all the answers

What is the effect of the ENS, ANS, and hormones on the amplitude of slow wave potentials?

They influence the amplitude of slow wave potentials (A) Signup and view all the answers

What is the characteristic of smooth muscle cells that allows them to contract in unison?

They are interconnected by gap junctions (B) Signup and view all the answers

What is the primary function of the splanchnic circulation?

To absorb nutrients from the gut (B) Signup and view all the answers

Which type of transport requires energy and involves transporters?

Primary active transport (A) Signup and view all the answers

What is the main site of absorption of major nutrients?

Small intestine (C) Signup and view all the answers

What is the movement of products of digestion from the lumen of the gut into the bloodstream or lymph?

Absorption (B) Signup and view all the answers

What type of smooth muscle cells produce the opposite effects of adrenaline and noradrenaline?

Contractile smooth muscle cells (D) Signup and view all the answers

What is the primary function of the motor neurons in the myenteric plexus?

Control of GIT motility (C) Signup and view all the answers

What is the estimated number of neurons in the enteric nervous system?

100 million (B) Signup and view all the answers

What is the primary function of the interneurons in the enteric nervous system?

Interconnection of neurons in the myenteric and submucosal plexuses (A) Signup and view all the answers

Where is the submucosal plexus, also known as the plexus of Meissner, located?

Within the submucosa (C) Signup and view all the answers

Which of the following is NOT a component of the enteric nervous system?

Cerebellum (A) Signup and view all the answers

What is the name of the plexus located between the longitudinal and circular smooth muscle layers of the muscularis externa?

Myenteric plexus (C) Signup and view all the answers

Where are the preganglionic sympathetic neurons that supply the GIT localized?

Thoracic and upper lumbar regions of the spinal cord (D) Signup and view all the answers

Which ganglion innervates the small intestine and the proximal part of the large intestine?

Superior mesenteric ganglion (D) Signup and view all the answers

What is the effect of stimulation of sympathetic nerves on the GIT?

Reduced motility and secretion of GIT (C) Signup and view all the answers

Which of the following is an example of a GIT reflex?

Response to chemical or mechanical stimulation of receptors in the GIT wall by food (B) Signup and view all the answers

Where do the postganglionic sympathetic fibers synapse in the GIT?

Myenteric plexus and submucosal plexus (B) Signup and view all the answers

Which of the following emotions may slow digestion?

Anger (A) Signup and view all the answers

What is the primary function of secretin in the gastrointestinal tract?

To stimulate the secretion of bicarbonates by pancreatic cells (C) Signup and view all the answers

Which of the following hormones is produced by I cells in the duodenum and jejunum?

Cholecystokinin (A) Signup and view all the answers

What is the primary function of histamine in the gastrointestinal tract?

To stimulate gastric acid secretion (D) Signup and view all the answers

Which of the following is a characteristic of paracrine agents in the gastrointestinal tract?

They are secreted by endocrine cells and act locally, without entering the systemic circulation (B) Signup and view all the answers

What is the primary function of somatostatin in the gastrointestinal tract?

To inhibit the secretion of gastrointestinal hormones and gastric acid secretion (D) Signup and view all the answers

What is the primary function of glucose-dependent insulinotropic peptide (GIP) in the gastrointestinal tract?

To inhibit gastric acid secretion and stimulate insulin secretion (D) Signup and view all the answers