cardiovascular physiology Flashcards
how is blood pressure monitored?
baroreceptors
what is the frank-starling mechanism?
if the ventricle stretches, it will contract with more force
ventricle stretches due to increase venous return which re-distributes blood to skeletal muscle = more forceful contraction
what happens when things go wrong with coronary circulation?
myocardial infraction
AKA heart attacj
clogged coronary arteries = no blood passage = part of myocardium dies off and becomes weaker
what is stroke volume?
the amount of blood per beat
what is vasodilation?
opening of blood vessels
what is the reason for nutrient exchange occuring in capillaries?
1) slow blood flow
2) thin vessel lining
what is the septum?
the part that divides the heart into left and right halves
function: prevent sideways flow of blood
why does the SV no longer increases after 60% intensity?
because the heart is beating so fast, diastolic has no time to fill back up with additional blood
what are coronary arteries?
branch directly off the aorta, supplying blood to the myocardium
what is diastolic blood pressure?
the pressure when the heart relaxes
when pressure bottoms out
what is coronary cirulation?
blood vessels that supply blood to myocardium
what is a hematocrit?
the number of RBC per volume of blood
why may you have high blood pressure?
1) narrowed blood vessels
2) increased blood volume
what is the difference of heart rate versus heart rhythm?
heart rate = the number fo times the heart beats per minute
heart rhythm = the pattern the heart beats at
how does exercise change cardiac output?
increases because HR and SV increases
what are b-adrenergic receptors?
receptors inside the myocardium that tells the heart to beat faster
what is vasoconstriction?
narrowing of blood vessels
what is the function of valves?
regulate blood flow between the chambers
what are the three layers of the heart?
1) pericardium
2) myocardium (heart muscle layer)
3) endocardium
how are blood vessels able to contrict?
the smooth muscle layer
how does exercise change blood pressure?
it depends
1) muscles contractions = vasoconstriction = higher BP
2) valsalva maneuver = hold your breath=high systolic = ruptured blood vessels
what is systolic blood pressure?
the pressure in the arteries when the heart contracts
how much blood are in males and females?
Males = 5-6L
females = 4-5L
how does the CNS control the heart rate?
1) medulla communicates with heart via
2) accelerator nerve to beat faster
OR
3) vagus nerve to beat slower
influenced by chemoreceptors and amgdyla (emotions)
how are red blood cells removed?
by the spleen
why does the heart require blood?
because it is a muscle too
what is A-VO2?
how much O2 was extracted by muscles as blood passes through
how does blood distribute durign exercise?
blood in internal organs shift over to the muscles
won’t be able to digest because blood is at skeletal muscles
how mant chambers are in the heart?
4 chambers
what is cardiac output?
the amount of bloof pumped out of left ventricle per minute
how does exercise affect stroke volume?
stroke volume rises to 110-130mL due to the fraank starling mechanism
how do we ensure blood gets back to the heart?
1) valves in veins
2) muscle pump
3) peripheral vasoconstriction
4) respiratory pump
**ONE AT A TIME**
why is an ECG while resting not sufficient when checking for myocardial infraction?
at rest, the heart looks normal.. once the heart is under stress, that is where we will see not enough blood gettingthrough to supply the working myocardium (depressed ST segment)
what is an ejection fraction (EF)?
the percentage of left ventricle volume ejected each beat
harder you work, higher EF % goes
NEVER 100% .. around 60%
what is te benefit of being “psyched up” during your workout?
increases HR + circulates processes faster = better workout
how does A-VO2 change during exercise?
it increases during exercise
- increase O2/CO2 concentration gradient, results in easier diffusion
