cardiovascular physiology Flashcards
what are inotrophy, chronotrophy, and dromotrophy
inotrophy (force of contraction)
chronotrophy (rate of contraction)
dromotrophy (conduction velocity)
what are the terms for slow and fast heart beats
bradycardia - slow heartbeat
tachycardia - fast heartbeat
what are the two types of cardiac muscle cells
conducting system cells (controls heartbeat) contractile cells (produce contractions to move blood)
what is automaticity of cardiac cells
the heart doesn’t need any external influence to beat, no nervous innervation or anything
what is the resting potential of ventricular cells
-90 mv
what is the resting potential of atrial cells
-80 mv
what is the major ion in cardiac muscle
Ca
what is the difference between the absolute refractory period and relative refractory period
aboslute refractory period comes before the relative refractory period, is long in duration, and the cardiac cells can’t respond to stimuli during it. during the relative refractory period muscle contractile cells can respond to stimuli, if it is strong enough
what is the difference between cardiac and skeletal muscle refractory periods, and why is it important
the cardiac muscle refractory period is much longer than the skeletal, this keeps the heart cells from using summation to reach tetanus
what are the structures though which the conducting system impulses pass beginning with the SA node and ending with contractile cells
SA node internodal pathways AV node AV bundle bundle branches perkinje fibers contractile cells
what is another name for the prepotential
pacemaker potential ( a gradual spontaneous depolarization)
how many action potentials do the SA and AV nodes produce per minute
SA node produces 80-100
AV node produces 40-60
what do the P, Q, R, S, and T of an EKG represent
P - atrial depolarization
QRS - ventricular depolarization (atrial repolarization)
T - ventricular repolarization
what does the P-R interval of the EKG represent
start of atrial depolarization to start of QRS complex (ventricular depolarization)
what does the Q-T interval of the EKG represent
ventricular depolarization to ventricular repolarization
what are the two phases of the cardiac cycle
systole (contraction)
diastole (relaxation)
when do we have end-diastolic volume
its the volume in the ventricle right before it contracts (at the end of relaxation/diastole) maximum blood volume
when do we have isovolumetric contraction
right after the AV valves close, and before the semilunar valves open
what is the amount of blood ejected from the heart during one systole called
stroke volume
when do we have end-systolic volume
after the ventricle has pumped out all the blood it can and the semilunar valve closes (end of systole) minimum blood volume
what percentage of end-diastolic volume remains as end systolic volume
40%
When do we have isometric relaxation
after the semilunar valves close, and before the AV valves open
how do you find stroke volume
EDV-ESV
what is cardiac output, and what influences it
volume pumped by left ventricle in one minute.
it is influenced by heart rate and stroke volume
what determines heart rate
autonomic nervous system and hormones
what nervous system increases heart rate
sympathetic nervous system
parasympathetic decreases heart rate
what are the two cardiac centers in the medulla oblongata
cardioacceleratory (SNS)
cardioinhibitory (PNS)
what nerves innervate the heart, and where do they come from
cardia plexus innervates the heart and comes from the vagus nerve
where do you find, and what is the function of cholinergic receptors in the heart
they are found in the SA node mostly, and they reduce heart rate (parasympathetic)
where do you find, and what is the function of adrenergic receptors in the heart
they are found in the SA node, and they increase heart rate and contraction force (sympathetic) and
what is the effect of angiotensin
increase contractility
what are the cardiac reflexes that control heart rate and contractility
baroreceptors that detect blood pressure
chemoreceptors that detect oxygen and CO2 levels
what is the atrial reflex, or bainbridge reflex
heart rate adjusts to venous return. more venous return = quicker heart rate
what two things affect EDV
filling time
venous return
what three things affect ESV
preload
contractility
afterload
what is the frank starling principle
as EDV increases SV increases (due to more volume and contractility)
what keeps the heart from stretching too much
myocardial connective tissue
cardiac (fibrous)skeleton
pericardial sac
