Kins 153- Final

how many chambers does the heart have & what are they?

4; L & R atria; L & R ventricles

how many layers does the heart have & what are they?

3; endocardium, myocardium, epicardium

what is the primary fxn of the left side of the heart?

pumps to general circulation in high resistance (high regulation)

what is the primary fxn of the right side of the heart?

pumps to pulmonary circulation in low resistance (10-20 mmHg pressure b/c low regulation)

what are the atrioventricular valves between & what are the names of the valves?

atria & ventricles'; right: tricuspid & left: bicuspid (mitral)

what are the semilunar valves between & what are the names of the valves?

ventricles & arteries; right: pulmonary semilunar & left: aortic semilunar

what does the fxn of the myocardium & where do the coronary veins return blood to?

actual work of pumping blood & receives blood from left (LA &LV) & right coronary arteries (RA, RV, & LV); right atria

how are is the heart muscle different from skeletal muscle?

cells are connected by leaky membranes, intercalated discs; cells depolarize as a unit & essential for efficient pumping (cells self depolarize; pacemaker cells have a faster leak & heart muscle have slower leak)

what does the heart depend on?

aerobic metabolism

during exercise how much does flow have to increase to provide fuel & oxygen to the heart & how does it occur?

4-6x; coronary vessels dilating & increase in pressure

what artery feeds the post R & L ventricle?

R coronary artery

what kind of fiber type is cardiac muscle like & what is its main metabolic process?

super slow twitch; mitochondrial respiration

where does most blood flow regulation occur?

b/w arteries & capillaries

why must cardiac fxn be regulated?

to control blood flow (i.e. O2/CO2 transport)

what is blood flow determined by?

cardiac fxn (SV, preload (venous return), afterload (TPR), contractility (strength of contraction), rate)

blood volume (total volume of blood in circulation (plasma + RBC))

arterial resistance (arterial tone (TPR) (resistance during exercise)) (TPR=mean arterial pressure/blood flow)

what can detect changes in blood volume?

indirectly through osmolality (salt concentration)

hypothalamus - ADH

what can detect changes in blood flow?

indirectly through pressure receptors (baroreceptors, kidneys, atrium)

through gas & ion concentrations (peripheral & central chemoreceptors)

where are the baroreceptors found & what do they do & when are they most predominant?

carotid & aortic bodies

reflex control (modulate CRC & ANS output); predominant at rest; must be reset during exercise (upper BP turned off)

what do chemoreceptors do & when are they most predominant?

detect changes in PaO2, PCO2, H+; reflex control (modulate CRC & ANS output); predominant at rest & exercise

how do the kidneys act as chronic BP regulator?

sense BP changes → release renin (strongest vasoconstrictor in body) which activates angiotensin I → converted by ACE in lungs to angiotensin II → cause adrenal glands to release aldosterone

cause kidney to conserve H2O & Na+; release powerful vasoconstrictors; angiotensin II via endothelin

how does the hypothalamus help w/ BP regulation?

release ADH

increase in osmolality or solute concentration; increase water Na+ retention by kidneys & thirst

how does the atrium help w/ BP regulation?

release ANP

counteracts high pressure; inhibits water retention & Na+ uptake b/ kidneys; antagonist of aldosterone (inhibits)

how does the CVC act to controls HR & BP?

ANS (SNS/PNS)

ANS acutely controls arterial tone (TPR), cardiac contractility & rate; very dynamic beat to beat & long term; HR variability

what occurs in cardiovascular regulation during exercise?

exercise increases central command & alters CVC fxn

CVC resets baroreceptors to higher threshold (systolic only)

CVC alters ANS output to CV sys (heart & circulatory sys); ANS increases SNS output & withdrawals PNS increases contractility & HR to increase pulse pressure & blood flow; blood flow redistribution

finetune regulation; baroreceptors, peripheral chemoreceptors, hypothalamus, kidneys provied feedback & fine tune BP regulation

what limits further dilation at VO2max for CV regulation?

local vasodilators

how much time is b/w atrial & ventricular contraction?

0.1s

how are ventricles fill?

mostly fill w/ blood passively, atrial contraction also helps fill ventricles

what does heart depolarization do?

depolarization creates an AP/electrical impulse that travels across the heart in an established pathway

what is the electrical pathway of the heart?

SA node → across atria → AV node → AV bundle → L & R bundle branches → purkinjie fibers → ventricles

what is the rate in the SA node, AV node, and ventricles?

SA node (60-100)

AV node (60-40)

ventricles (20-40)