Anatomy of the Enteric Nervous System

Which part of the GI tract wall does the Myenteric Plexus provide major nerve supply to?

Entire GI tract wall (correct)
Only the mucosal epithelium
Submucosa and mucosal epithelium
Longitudinal and circular smooth muscle layers

What is the primary function of the motor neurons in the Submucosal Plexus?

Control of GI tract motility
Regulation of the autonomic nervous system
Integration of sensory information
Supplying the secretory cells of the mucosal epithelium (correct)

What type of receptors are chemoreceptors and stretch receptors examples of?

Nociceptors
Interneurons
Sensory neurons (correct)
Mechanoreceptors

What is the role of the autonomic nervous system in relation to the enteric nervous system?

It regulates the activity of the enteric nervous system (C) Signup and view all the answers

What is the term for reflexes that involve the CNS as an integration center?

Long reflexes (D) Signup and view all the answers

What is the composition of GI hormones?

Amino acid-based (D) Signup and view all the answers

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

They interconnect the neurons of the myenteric and submucosal plexuses (D) Signup and view all the answers

What is the relationship between short and long reflexes?

They occur simultaneously (A) Signup and view all the answers

What is the primary function of the receptive relaxation of the fundus and body of the stomach?

To allow for approximately 1 liter of food to enter the stomach (C) Signup and view all the answers

What is the role of the interstitial cells of Cajal in the stomach?

To establish the basic electrical rhythm in the stomach (A) Signup and view all the answers

What is the effect of a lipid-rich meal on gastric motility?

It decreases the rate of gastric motility (D) Signup and view all the answers

What is the role of the vagus nerves in the stomach?

To supply parasympathetic fibers to the stomach (C) Signup and view all the answers

What is the function of the gastric accommodation reflex?

To inhibit the stress-relaxation response (C) Signup and view all the answers

What is the effect of distension of the stomach wall on gastric motility?

It increases the force of gastric contractions (D) Signup and view all the answers

What is the role of the celiac trunk in the stomach?

To provide arterial blood supply to the stomach (D) Signup and view all the answers

What is the volume of chyme that is squirted into the small intestine with each peristaltic wave?

3 mL (D) Signup and view all the answers

What is the primary function of enteric bacteria in the large intestine?

To ferment indigestible carbohydrates and release irritating acids and gases (C) Signup and view all the answers

What stimulates the rate of mucus secretion in the large intestine?

Tactile stimulation of the mucous cells and local nervous reflexes (A) Signup and view all the answers

What is the primary function of mucus in the large intestine?

To provide an adherent medium for holding fecal matter together (A) Signup and view all the answers

What is the approximate daily volume of gas produced by enteric bacteria in the large intestine?

500 ml (D) Signup and view all the answers

What is the role of the parasympathetic system in the large intestine?

To increase motility and stimulate the release of digestive enzymes (C) Signup and view all the answers

What is the function of mucus in protecting the intestinal wall against bacterial activity?

It provides a barrier to prevent bacterial adhesion (C) Signup and view all the answers

What primarily results in the demineralization of enamel and dentin leading to cavities?

The bacterial conversion of sugar to acid (D) Signup and view all the answers

How does accumulated dental plaque contribute to gum infections?

By increasing the depth of the gingival sulcus (C) Signup and view all the answers

What condition results when gingivitis is untreated and immune cells cause additional tissue damage?

Periodontal disease (D) Signup and view all the answers

Which risk factor is associated with an increased occurrence of periodontal disease?

Smoking and oral piercings (D) Signup and view all the answers

What defines an impacted tooth?

A tooth embedded in the jawbone (A) Signup and view all the answers

What physiological change causes teeth to appear longer in old age?

Adherence of gingiva to the cementum (D) Signup and view all the answers

Which part of the pharynx is not involved in the digestive system?

Nasopharynx (C) Signup and view all the answers

What is a primary function of the pharynx related to digestion?

Propelling food to the esophagus via peristalsis (B) Signup and view all the answers

What triggers the contraction of the longitudinal muscle layer during migrating motility complexes?

Distal impulses to the longitudinal muscle layer (B) Signup and view all the answers

What is the primary function of slow, segmenting contractions in the colon?

Absorption through epithelium (C) Signup and view all the answers

Which reflex is involved in aiding mass movements in the colon?

Gastrocolic reflex (C) Signup and view all the answers

What is the role of the proximal area during the migrating motility complexes?

It contracts to force chyme along the tract (D) Signup and view all the answers

What is the initial signal for the spinal cord-mediated defecation reflex?

Distention of the rectal wall (C) Signup and view all the answers

How frequently do migrating motility complexes occur overnight?

6-8 times per night (C) Signup and view all the answers

What is formed by the combined contractions of the longitudinal and circular muscle of the colon?

Haustrations (A) Signup and view all the answers

Which muscle layer contracts proximally during migrating motility complexes?

Circular muscle layer (A) Signup and view all the answers