2.10 Flashcards
what is the hormonal regulation of circulation?
vasoconstriction
- NE -> a1 R -> Gq -> [Ca++] ↑ -> vasoconstriction
- Angiotensin II activates AT1 R (Gq)
- Vasopressin (V1 R -> Gq)
- Histamine, Serotonin -> Gq
- Endothelin
what is the hormonal regulation of circulation?
vasodilation
- E from adrenal glands -> B2 R -> Gs -> [cAMP] ↑ ->PKA ->?????????????
- ANP
- PGI2
what is the neural regulation of circulation?
symp is the most important in relation to skin and skeletal muscles
what is MAP?
Mean Arterial blood Pressure= average pressure in a patient’s arteries during one cardiac cycle
MAP = [SBP + 2x(DBP)]/3
value of MAP
~93 mmHg
which vessels does the sympathestic NS innervates?
- resistsnce vessels (arterioles!)
- capacitance vessels (veins. their compliance decrease in symp innervation)
- heart (SA, AV, cardiac muscle)
where can we find high pressure baroreceptors?
in arteries (bcs there we have high pressure)
in high pressure baroreceptors we have fast acting baroreceptors which are located in
- carotid sinus baroreceptors (increased pressure -> this baroreceptors will expand
- aortic baroreceptors (same mechanism)
what is the range of sensitivity for carotid sinus BR?
50-200 mmHg
low and high pressure detection
what is the range of sensitivity for aortic BR?
100-200 mmHg
to where does the carotid sinus BR send the info?
carotid sinus -> carotid sinus nerve -> solitary nucleus -> leading to parasymp or symp response
to where does the aortic BR send the info?
aortic arch -> vagus fibers -> solitary nucleus -> leading to parasymp or symp response
in high pressure baroreceptors we have slow acting baroreceptors which are located in
Renin-Angiotensin System
in the Renal artery
Afferent arterioles
where can we find low pressure baroreceptors?
venous system
what do the low pressure baroreceptors sense?
sense increase in blood volume
location of low pressure baroreceptors?
- Sup and Inf Vena-Cava (B fibers)
2. Sinus Venarum Cavarum (A fibers)
how will the increase in blood volume effects low pressure baroreceptors?
IV infusiopn -> increase right atrial pressure -> receptor stimulation -> HR↑ and hormaone regulation to increase excretion of Na+ in an effort to lower thr blood volume
location of the peripheral chemoreceptors?
bifurcation of the common carotid
along the aortic arch
what are the peripheral chemoreceptors sensitive to?
changes in the arterial pressure of O2
also to increase partial pressure of CO2 and decreased pH
where can we find central chemoreceptors?
medulla
reticular formation
what are the central chemoreceptors sensitive to?
most sensitive to partial pressure of CO2
also pH
**less sensitive to O2
explain Cushingreflex
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