EX 2; Regulation of Systemic Arterial Pressure Flashcards
This is the sum of the resistances to flow offered by all the systemic blood vessels
TPR; total peripheral resistance
What is the equation for MAP
MAP = CO x TPR
All changes in MAP must be the result of changes in what two things
cardiac output
TPR
What is the equation for CO
CO = HR x SV
Dynamic changes in vasodilation/vasoconstriction due to changes in the resistance of these can alter the MAP
arterioles
This occurs to protect the maintenance of MAP
compensatory changes in arteriolar resistance
What is the equation for flow
change in pressure/resistance
Which portions of the body have their MAP regulated by local control
heart and brain
needed to control their own BP
What portions of the body have their MAP regulated by neuronal control
GI
skeletal muscles
epithelium, etc.
The sympathetic system acts upon which parts of the heart
atria and ventricles
Sympathetic input to the SA node is via which receptors/channels
β receptor
funny channel
Parasympathetic input uses this receptor/channel
muscarininc receptor
funny channel
Sympathetic input to the vessels is via which receptor
α receptors
How does the sympathetic system increase HR via the use of α and β channels
α on the vessels = vasoconstriction = increased TPR
β on ventricles = increased contractility and increased Ca = increased SV
Blood loss causes a reduction in MAP, which is left unchecked would result in what
rapid and irreversible damage to the brain and the heart
These function as sensors in the homeostatic maintenance of MAP by constantly monitoring pressure in the aortic arch and carotid sinus; *Main short term way to regulate MAP
baroreceptors
The action potential frequency in baroreceptor neurons is represented here as being directly proportional to what
MAP
Baroreceptor neurons deliver MAP information to where
the medulla oblongata’s cardiovascular control center; CVCC which determines autonomic output to the heart
The information reported by baroreceptor neurons sets in motion autonomic responses to the heart (via CVCC) but also to where
arterioles and veins; this allows MAP to more readily be moved closer to the “set point”
If arterial pressure decreases, the discharge rate of the baroreceptor does what
decreases
What four things does a decrease in baroreceptor function induce
increased HR due to increased sympathetic activity and decreased parasympathetic activity
increased ventricular contractility (sym. activity)
arteriolar constriction (sym. activity)
increased venous contraction (sym. activity)
The long term way to regulate blood pressure is through the use of what
an abnormal increase in MAP “squeezes” ,pre fluid out of the blood into the urine, leading to a reduction in blood volume, thus reducing MAP to the “set point”
