heart part II Flashcards
occlusion
blockage
ischemia
blood deficiency in a breach of coronary artery often due to constriction/blockage from clot
angina pectoris
chest pain that accompanies ischemia
myocardial infarction
heart attack; death to portion of heart due to ischemia
cardioacceleratory center (CAC)
medulla oblongata; sympathetic- INCREASE heart rate
sympathetic nerve fibers
leave CAC region in medulla oblongata; INCREASE rate/strength of heartbeat
parasympathetic nerve fibers
leave CIC region to HEART via vagus nerve (cranial X); DECREASE heart beat
cardioinhibitory center (CIC)
medulla oblongata to heart via vegas nerve (cranial X)- parasympathetic DECREASE heart rate
What is responsible for increase heart rate
sympathetic nerve fibers in CAC (medulla oblongata)
What is responsible for decrease heart rate
parasympathetic nerve fibers in CIC (medulla oblongata)
vagus nerve
cranial X; parasympathetic nerve fibers leave CIC via this route to slow heart rate
intrinsic regulation
nervous system WITHIN heart itself
where is sino-atrial node (SA node)
posterior of right atrium beneath epicardium below superior vena cava
SA node aka
pacemaker of heart
why is SA node called pacemaker of heart
starts action potentials (intrinsic regulation)
where do action potentials from SA node spread to
both atria (contract together)
where is atrioventricular node (AV node)
floor of right atrium
where does action potential spread to from AV node
AV bundle (bundle of His)
action potential location after bundle of His
through inter ventricular septum to left/right bundle branches
where do bundle branches carry action potential to
purkinje fibers
purkinje fibers
carry action potential of heart into cells of myocardium and cause ventricles to contract
which ventricle pumps harder right or left
left ventricle bc it has to pump systemic blood to whole body
3 periods of cardiac cycle
mid-to-late diastole, ventricular systole, early diastole
mid-to-late diastole
heart in complete relaxation; blood is filling atria (ventricles slightly bc AV valve is open)
BP in mid-to-late diastole
low BP
When is mid-to-late diastole completed
when SA node fires action potential, causes atria to contract (atrial systole) and push remaining blood into ventricles
why do atria contract
to squirt out remaining 30% of blood into ventricles that didn’t go there in mid-to-late diastole
systole alone
contraction of ventricles
Ventricular systole
ventricular contraction; pressure increases rapidly; AV valves close (LUB) semilunar valves open, blood rushes out of ventricles, begin to relax, semilunar valves close (DUB)
What is occurring at the same time as ventricular systole
atrial diastole
What makes the LUB DUB sounds in heart
in ventricular systole (ventricular contraction) LUB=AV valves snapping shut before contraction, DUB=semilunar valves snapping shut after contraction
Early diastole
intraventricular pressure drops below pressure in atria and AV valves open. REPEAT of cardiac cycle
pressure in ventricular systole
high pressure; rapid increase
What does the strength of contraction in heart depend on
volume of blood
Starling’s Law
heart pumps blood that comes in w/o excessive damming of blood in veins; more heart wall is stretched=greater contraction (heterometric auto regulation)
heterometric autoregulation
more heart wall is stretched=greater contraction to prevent damage to veins and capillaries (starlings law)
What reflex controls heterometric autoregulation
bainbridge reflex
bainbridge reflex
controls heterometric autoregulation
stroke volume
amount of blood pumped from left ventricle to aorta per heart beat; amount of blood going to whole body in a single heart beat
cardiac output
stroke volume times beats/min
amount of blood pumped from left ventricle to aorta per minute
auscultation
act of listening to heart sounds
murmurs
turbulence=damaged valves (blood flow is supposed to be smooth)
stenosis
incomplete opening of valves
insufficiency of valves
incomplete closure
two types of heart murmurs
stenosis or insufficiency of valves
how can you detect heart murmur
stethoscope
affects of K+ and Na+ on heart
inversely proportional (increase=heart rate decrease) and vice versa
Ca+2 affect on heart
directly proportional; increase=increase heart rate
affect of temperature on heart
directly proportional; increase=heart rate increase
male vs female heart rate
male rate=lower than female
fear and anger (aka?) on heart rate
epinephrine (adrenaline); increase heart rate
greif on heart rate
stimulates CIC; decrease heart rate
aortic aneurysm
burst/hemorrhage; weakness in BV/bulge
