Cardiophysiology Flashcards
4 types of tissue
nervous, muscle, epithelial and connective tissue
3 types of muscular tissue
skeletal, smooth, cardiac
where is the heart located
within the thorax, on the left
arteries
carry blood away from the heart
veins
carry blood toward the heart
ascending aorta
feeds the brain and the upper body
descending aorta
feeds lower body
coronary artery
ring around the heart; feeds the heart
ischemia
reduce blood flow to a body part, such as the brain
right coronary artery feeds
right ventricle, and consequently the lungs
left coronary artery feeds
left ventricle, and consequently the rest of the body
deoxygenated blood
is pumped into pulmonary (lungs) circuit by the right side of the heart
oxygenated blood
comes back from the pulmonary system and the left side of the heart distributes it
valve
ensure one-way blood flow
LAB RAT
left atrium bicuspid; right atrium tricuspid
heart mummer
irregular heart beat caused by leak in the valve
blood flow
1) right atrium
2) through the tricuspid valve, into the right ventricle
3) through pulmonary valve to pulmonary trunk and arteries
4) within pulmonary capillaries blood becomes oxygenated
5) the oxygenated blood goes to the pulmonary veins
6) left atrium to bicuspid valve
7) left ventricle to aortic valve
8) aorta & systemic arteries
9) within the systemic capillaries, the blood becomes deoxygenated
10) superior and inferior vena cava and coronary sinus carry the blood back to the right atrium
autorhythmic cells function
make action potentials without the nervous system stimulation
autorhythmic cell cycle
1) when the membrane potential is -60mV; If channels open (K+ and Na+ channels open; Na+ rushes into the cell faster than K+ leaves, and the threshold increases)
2) at -40mV, the If channels closes and the Ca2+ T-channels open and Ca2+ rushes in. Ca2+ L-channels (slow) also opens -> action potential rising phase
3) at the peak of the A.P., the Ca2+ T-channels first close, then the L-channels and slow K+ channels open causing repolarization to -60mV
4) at -60mV the process starts again
SA node causes
waves of action potential across the atrium and forces the blood down the ventricle
contractile cells function
moves blood through the heart
contractile cells process
1) resting potential is at -96 mV
2) initial depolarization via Na+ influx (Na+ channels open); threshold is -52mV
3) repolarization when Cl- and K+ go out the cell
4) plateau phase due Ca2+ influx and K+ efflux
5) repolarization due to K+ slowly leaving the cell
systole
heart contraction
diastole
ventricle relaxes
order of stimultion
SA node -> AV node -> bundle of His -> branches to left and right ventricles -> purkinje fibers
automatic nervous system
controls heart rate
sympathetic
fight or flight; raises heart rate via catecholamines increasing Na+ influx and calcium cycling in autorhythmic cells -> faster depolarization & recovery
parasypathetic
slows heart rate via Ach increasing K+ efflux lessening Na+ influx in autorhythmic cells
EKG
measures electrical conduction in the heart
P wave
atrial depolarization
QRS complex
ventricle depolarization (also atrial repolarization but it is “buried” )
T wave
recovery wave; ventricle repolarization
pressure - volume loop
relationship between ventricular volume and fluid pressure
isovolumetric ventricular contraction
first heart sound; blood hits against valve
ventricular ejection
semi-lunars open, blood leaves ventricle; amount moved: ESV-EDV
isovolumetric ventricular relexation
same volume, decreased blood pressure
cardiac output (Q)
measures volume in the heart (beat per minute / L per beat) ; average is 5L
two P waves on an EKG
SA node is fine, but AV node has issues
semilunar valves
aortic and pulmonary valve
bicuspid valve is also called
mitral valve
what starts the heart cycle
the firing of the SA node depolarizes the atria (P-wave)
what is sound 1
after atrial systole, when the blood is pushed from the atrium to the ventricles, the blood wants to go back up where the pressure is lower. However the valves (tricuspid and mitral) are closed, so the turbulence causes the sound
what is sound 2
ventricle pressure is falls below the pulmonary and aortic pressures and the semilunar valves closes (the blood wants to go back to low blood pressure, but it can’t)
isovolumetric contration
ventricles is filled with the blood from the atrium and the ventricle contracts while the semilunar valves are closed; the ventricle pressure increases, while the volume remains the same
ventricular systole
starts when the ventricle pressure is higher than the aortic and pulmonary valves, the semilunar valves open, and blood rushes out the ventricle
ventricular repolarization begins, ventricular pressure falls and the rate of ejection is lower
early ventricular diastole
semilunar valves close (S2), the ventricle relaxes but the valves are closed -> pressure decreases while the volume stays the same
late ventricular diastole
ventricular pressure drops below the atrial pressure (it was filling up with blood during the ventricular diastole), the tricuspid and mitral valves (AV valves) open, and the blood flows to the ventricle
atrial systole
atrial depolarization, atria contracts and its pressure increases, forcing blood into the ventricles
ESV
end systolic volume (blood in ventricle after contraction)
EDV
end diastolic volume ( ventricle is filled with blood)
cardiac output (Q)
stroke volume * heart beat
vasoconstriction
increase resistance, reduce blood flow
counterbalance by increasing pressure
dilation
decrease resistance, (pressure increases)
