Physiology Flashcards
Enteric nervous system comprises what
Myenteric and submucosal plexuses
Vagal-Vagal reflex: afferents go where
Nodose ganglion
Vagal vagal reflex: Efferents come from where?
NTS: Nucleus Tractus Solitarius
Gastrin: Source?
Stimuli of secretion
-G cells of stomach
- small peptides and aa
- Distention
- vagal stimulation (via GRP)
CCK: source?
Stimuli of secretion?
I cell of duodenum and jejunum
- Small peptides and a.a.
- Fatty acids
Secretin: source?
Stimuli of secretion?
S cell of the duodenum
- H+ in duodenum
- Fatty acids in duodenum
GIP: source?
stimuli of secretion?
What does it do?
Duodenum and jejunum
- Glucose
- stimulates insulin
What does the NT VIP do?
- relaxation of smooth muscle
- increase intestinal and pancreatic secretion
what does the NT GRP do?
-increases Gastrin secretion
What 2 NTs are used for food intake regulation
- Neuropeptide Y
- Substance P
What is it called when the GI smooth muscle, even subthreshold depolarizes and can produce weak contraction
Basal Contractions
Sub thrshold depolarization and repolarization of the GI membrane potential
slow waves
What 3 things stimulate depolarization of the slow waves?
what stimulates hyper polarization?
- stretch
- ACh
- Parasympathetics
- Norepinephrine
- Sympathetics
pacemaker for GI smooth muscle
Interstitial cells of Cajal (ICC)
slow waves occur spontaneously in the ICC and spread how
gap junctions
Smooth muscle cells response to slow wave depolarization with increased what?
Ca2+ channel open probability
3 phases of swallowing
- Oral phase
- pharyngeal phase
- Esophageal phase
involuntary swallowing reflex is controlled by what?
the medulla
What nerve sends afferent sensory input due to food in the pharynx to the swallowing center in the medulla?
Glossopharyngeal N.
Esophageal phase of swallowing contains what 2 types of peristaltic waves?
primary and secondary
Which wave of the esophageal phases can still occur after a vagotomy
secondary
Receptive relaxation occurs in what region of the stomach
orad
What does CCK do to the contractions and distensibility of orad region upon reception of food
- decreases contractions
- increases distensibility
how long does gastric emptying take
3 hours
What secretion from the duodenum inhibits gastric emptying
CCK
Large particles of undigested residue remaining in the stomach are emptied by what
Migrating myoelectric complexes (MMC)