25 Questions
Which cranial nerve is responsible for the innervation of the Parotid gland?
IX cranial nerve
What is the primary function of the propulsive contractions mediated by the PS nerves in the myenteric plexus?
To move the bolus further along the tube
Which muscles are responsible for mechanical homogenization during the oral phase of swallowing?
Intrinsic lingual muscles
How long does it take for the bolus to travel from the pylorus to the ileocecal valve?
3-5 hours
Which nerve provides innervation to the mandibular muscles of the jaw?
V3 cranial nerve
What is the location of the submucosal plexus in the intestinal wall?
Submucosa
What is the function of the myenteric plexus in the intestinal motility?
Mixing and propulsion of food
What type of muscle is innervated by the myenteric plexus?
Smooth muscle
What is the role of mechanoreceptors in the myenteric plexus?
Modulation of the autonomic nervous system
What is the diameter range of the fibres that interconnect the two muscle layers in the intestinal wall?
2-10 microns
Which type of neurons carry sympathetic fibres to the myenteric and submucosal plexuses?
Postganglionic neurons
What is the primary function of the myenteric plexus?
Motility
What is the effect of the submucosal plexus on the submucosal muscle?
Contractions
What is the purpose of segmentation contractions in the gastrointestinal tract?
To mix the contents of the chyme and increase absorption
What is the effect of VIP (vasoactive intestinal peptide) on the pyloric sphincter and the ileocecal valve?
Relaxation
What is the primary mechanism by which the central nervous system influences primary peristalsis in the esophagus?
Through the stimulation of the vagus nerve
What is the role of VIP and NO in secondary esophageal peristalsis?
They are relaxants of the circular muscle layer
What is the response of the esophageal muscle layers above the bolus level during secondary peristalsis?
Circular layer contraction, longitudinal layer relaxation
What is the primary function of the dorsal motor nucleus in the context of esophageal peristalsis?
To innervate the smooth muscle of the esophagus
What is the trigger for the activation of secondary esophageal peristalsis?
The failure of primary peristalsis to clear the bolus
What type of muscle is present in the upper third of the esophagus?
Striated muscle
Which nerves are responsible for the innervation of the striated muscle in the upper esophagus?
IX and X cranial nerves
What is the name of the muscle that relaxes to allow the passage of food into the esophagus?
Cricopharyngeal muscle
What is the term for the peristalsis that occurs in response to esophageal distension?
Secondary peristalsis
How long does it take for the food bolus to pass through the esophagus?
5-10 seconds
Explore the intricate workings of the esophagus, including the myenteric plexus, vagus nerve, and neuromuscular mechanisms. Learn about the central and peripheral nervous systems' roles in peristalsis and smooth muscle activation.
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