H E A R T Flashcards
blood flow through the heart
- right atrium
- right AV valve
- right ventricle
- pulmonary SL valve
- pulmonary artery
- lungs
- pulmonary veins
- left atrium
- left AV valve
- left ventricle
- aortic SL valve
- aorta
what are the 3 layers of the heart wall?
- epicardium
- myocardium
- endocardium
epicardium
(visceral pericardium) - often infiltrated with fat
myocardium
mainly cardiac muscle (contractile layer)
endometrium
thin layer of endothelium
what are the 4 heart valves?
prevents back flow
- tricuspid (AV) valve
- pulmonary (SL) valve
- bicuspid (mitral/AV) valve
- aortic (SL) valve
tricuspid (AV) valve
connects right atrium to right vetricle
pulmonary (SL) valve
connects right ventricle to pulmonary trunk
bicuspid (mitral/AV) valve
connects left atrium to left ventricle
aortic (SL) valve
connects left ventricle to aorta
cardiac muscle action potential
upstroke: Na+ influx
plateau: Ca2+ influx
depolarization: K+ efflux
what anatomical structure is the primary pacemaker of the heart?
sinoatrial (SA) node
what are the purposes of intercalated discs in heart muscle?
communication to coordinate contractions
ECG: P-wave
atrial depolarization (SA node)
ECG: PQ
signal delay at AV node
ECG: QRS
ventricles: depolarize
atrium: repolarize
ECG: ST
ventricles: depolarization complete
ECG: T-wave
ventricles repolarize
what would happen in pacemaker cells became more permeable to potassium ions?
K+ slows depolarization, so decreased heart rate (HR)
what would happen in pacemaker cells became more permeable to sodium ions?
Na+ speeds up depolarization, so increased heart rate (HR)
tachycardia
fast heart rate
bradycardia
slow heart rate
what physiological events are represented by the 1st and 2nd heart sounds?
S1: “lubb”: closing AV valves
S2: “dupp”: closing SL valves
relate AV and SL valves closing to ventricular systole and diastole
systole: AV close, SL open
diastole: AV open, SL close
SNS affect on HR and CO
release NE (opens Na+ and Ca2+ to speed up depolarization)
increased HR & CO
PNS affect on HR and CO
release Ach (opens K+ to slow depolarization)
decreased HR & CO
what is the effect of increased or decreased systolic and diastolic blood pressure affect stroke volume?
increased BP
Increased after load
decreased stroke volume
(have more resistance)
EDV definition
end diastolic volume
volume in ventricle at end of diastole (volume available for ejection)
~120ml
ESV definition
end systolic volume
volume left in ventricle at the end of systole (after ejection)
~60ml
how would increased contractile force in the left ventricle effect ESV?
decrease ESV
