30 Questions
Which cranial nerve nucleus contains alpha-motoneurons that supply the muscles of the palate, pharynx, and larynx?
Nucleus ambiguus
Which nucleus has alpha-motoneurons that supply the intrinsic and extrinsic muscles of the tongue?
Cranial nerve XII nucleus
What is the name of the brainstem center that comprises the central neural pattern generator for chewing?
Chewing center
Which component of chewing can be overridden by voluntary control?
Involuntary component
What is the unique feature of the trigeminal mesencephalic nucleus?
It is the only site in the body where primary cell bodies are located within the CNS.
How do orofacial muscles compensate for the weakness of reciprocal innervation due to the lack of proprioceptors?
Through powerful regulatory influences from afferent impulses
What type of hormone is GLP-1 classified as?
Incretin
Which hormone is secreted by D cells of the gastrointestinal mucosa in response to decreased luminal pH?
Somatostatin
What is the primary function of histamine secreted by cells in the stomach?
Stimulate gastric acid secretion
Which type of hormone is synthesized in cell bodies of gastrointestinal neurons?
Neurocrine
What effect does somatostatin have on other gastrointestinal hormones?
Inhibits their secretion
Which cells secrete GLP-1 in the small intestine?
L cells
What neurotransmitter do postganglionic nerve fibers release?
Norepinephrine
Which plexuses can postganglionic nerve fibers synapse on?
Myenteric and submucosal plexuses
What effect does gastrin have on gastric motility?
Stimulates ileal motility
How is gastrin secretion inhibited?
By negative feedback from acid accumulation in the stomach
What stimulates the release of cholecystokinin (CCK)?
Fat and other nutrients entering the duodenum
How does CCK affect the digestive system?
Stimulates bile release from the gallbladder
During which phase of the slow waves in the gastrointestinal tract does the balance of inward calcium current and outward potassium current occur?
Phase 3
What is the frequency of electrical slow waves in the human antrum?
3 waves/min
What initiates changes in sphincter pressure for gastrointestinal tract contents to move through?
Smooth muscle contractions in adjacent organs
Which type of muscle action potentials appear at the crests of the slow waves in the gastrointestinal tract?
Sharp upward-downward deflections
What is the characteristic of muscle contractions associated with each slow wave?
Small contractions with no action potentials
Which phase of the slow waves is characterized by activation of voltage-gated calcium channels?
Phase 1
What drives colonic contents into the distal part of the large intestine?
Mass movements
How many times per day can mass movements occur?
1 to 3 times
Which reflex triggers mass movements in the colon primarily?
Gastrocolic reflex
What is responsible for making the fecal contents of the large intestine semisolid?
Water absorption
What reflex moves remaining small intestine contents into the large intestine?
Gastroileal reflex
Which reflex triggers the defecation reflex by pushing colonic contents into the rectum?
Gastrocolic reflex
Test your knowledge on how gastrointestinal tract contents move through sphincters, coordinated muscle contractions, control of digestive system activities, and phases of slow waves in the digestive tract.
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