Neuro Flashcards
nucleus of the medulla that contains the preganglionic neurons of the parasympathetic, innervating esophagus, heart and respiratory systems
nucleus ambiguus
CN X projects to
parasympathetic ganglia of heart, lungs, liver, gall bladder, pancreas, stomach, small intestine and rostral segments of GI tract
Where is the sympathetic preganglionic cell column
in the intermediolateral cell column from T1 to L3
What parasympathetic ganglion innervates the heart and lungs
stellate ganglion
Why is referred pain felt with myocardial injury?
nociceptive efferents from the viscera and areas of the skin converge on the same projection neurons in the dorsal horn. The brain cannot tell what the source of the original signal was.
Which cardiac nerve has more effect on HR?
right cardiac nerve (postganglionic fibers release NE)
Which cardiac nerve has more effect on contractility?
left cardiac nerve
Which nucleus does afferent fibers of baroreceptors project to?
NTS
release glutamate which binds to AMPA and GluR2
part of the vasomotor area of the ventrolateral medulla that evokes a vasoconstrictor response when stimulated
C1
the NTS neurons inhibit this when blood pressure is elevated
it is responsible for the vascular response of the baroreceptor reflex
Note: clonidine binds to imidazole receptors on C1 neurons
which nuclei are responsible for the bradycardia aspect of the baroreceptor reflex?
nucleus ambiguus and dorsal motor nucleus of the vagus
which vagus nerve is a more effective inhibitor of conduction through the AV node
left vagus
which vagus nerve inhibits HR?
right vagus
Where are the cell bodies of the CN IX?
petrosal ganglion
Where are the cell bodies of the aortic baroreceptor?
nodose ganglion
Which fibers of the atrial low pressure sensors monitor atrial filling?
B fibers
these monitor venous return
Which nucleus synthesizes vasopressin and releases it in response to atrial low-pressure sensor firing?
PVN of the hypothalamus
How does a beta-1 agonist exert an inotropic effects on the myocardial cells?
through protein kinase A
alpha-s subunit directly activates L-type calcium channels
how does M3 activation lead to vasodilation?
increases intracellular calcium which then stimulates NO synthase. NO synthase indirectly inhibits calcium influx through L-type channels
Why do coronary bvs dilate in response to epinephrine?
coronary bvs have more beta-2 receptors than alpha-1, so vasodilation is the dominant response
Why is epinephrine not a systemic vasodilator?
beta-2 receptors are concentrated in skeletal muscle, liver, heart and adrenal medulla
how does bradykinin promote vasodilation?
binds to beta-2 receptor on endothelial cells and causes release of NO and prostaglandins
Which part of the hypothalamus mediates decrease in body temp?
anterior
panting, vasodilation, suppression of shivering
which part of the hypothalamus mediates increase in body temp?
posterior
shivering
Loss of consciousness in response to emotional stress: Bezold Jarisch reflex
vasovagal response
vagal afferents carry signal to higher CNS centers and result is massive PNS stimulation abolishing sympathetic tone
This causes massive vasodilation and the drop in blood pressure does not elicit the baroreceptor response.
Decreased MAP causes global cerebral ischemia. Hyperventilation decreases PCO2 and further decreases cerebral flow by causing vasoconstriction.
End result: bradycardia and decreased CO from intense vagal output
Phases of valsalva response
Phase I: increased BP causes decreased HR
Phase II: decreased venous return decreases MAP -> reflex tachycardia & peripheral vasoconstriction
(release)
Phase III: decreased intrathoracic pressures decreases BP and increases HR
Phase IV: rapid venous return increases BP & get overshoot of BP with reflexive bradycardia after 5-6 seconds
