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3 things regulated to ensure MAP is maintained
blood vessels, heart, blood vessels
systolic BP (top number)
pressure in arteries when heart contracts and pushes blood.
diastolic BP (bottom number)
pressure in arteries when heart is relaxed and filling with blood
MAP=
cardiac output X total peripheral resistance
what is mean arterial blood pressure?
the avg. pressure driving blood towards tissues during cardiac cycle.
why is MAP used in clinical settings as opposed to systolic and diastolic BP?
better indication of overall blood flow, organ perfusion and pressure in arteries
pulmonary circuit
right side, sends blood
systemic circuit
left side
systole
contraction
diastole
relaxation
cardiac output (liters/min)=
heart rate (beats per min) X stroke volume (liters per min)
what is cardiac output?
the amount of blood pumped by a ventricle in a period of time
2 types of cells in the heart
autorhythmic and myocardial cells
autorhythmic cells (1% of heart cells)
set the heart rate
generate own AP’s,
AP’s move to other cells via gap junctions
do NOT require ANY input from ANS
pumping cells (99% of cells in heart)
lots of actin and myosin
do all contracting work
receive AP’s from AR cells via gap junctions
vasodiilators
nitric oxide, ANP, histamine
anaphylaxis
systemic effect causing widespread release of histamine, widespread vasodilation and decreased MAP
vasoconstrictors
ANG II ADH
describe the action potential in autorhythmic cells
rapid voltage gated Ca channels caused by depolarization, followed by increased, permiability to Ca, followed by K+ efflux to repolarize
