the heart pt2 Flashcards
cardiac cycle is what
one complete contraction and relaxation of all four chambers of the heart
what two variable govern fluid movement
pressure causes flow
resistance opposes it
fluid will only flow if there is a what?
pressure gradient(difference)
pressure is measure in what?
mmHg
opening and closing of valves are governed by these pressure changes:
AV valves limp when ventricles are relaxed
semilunar valves under pressure from blood in vessels when ventricles relaxed
valvular insufficiency(incompetence) is what
any failure of a valve to prevent the backward flow of blood
valvular stenosis is what?
cusps are stiffened and opening is constricted by scar tissue
valvular stenosis is a result of what?
rheumatic fever, an autoimmune attack on the mitral and aortic valves
heart murmur is what
an abnormal heart sound produced by regurgitation of blood thru incompetent valves
mitral valve prolapse is what
insufficiency in which one or both mitral valve cusps bulge into atria during ventricular contraction
auscultation is what
listening to sounds made by body
first heart sound is what
louder and longer because of closure of AV valves
second heart sound is what
softer and sharper because of closure of semilunar valves
phases of cardiac cycle
ventricular filling
isovolumetric contraction
ventricular ejection
isovolumetric relaxation
how long is the cardiac cycle
less than 1 second
ventricular filling is what
ventricles expand their pressure drops below that of the atria
second step of ventricular filling
AV valves open and blood flows into ventricles
filling of ventricular filling happens in three phases
rapid ventricular filling- first
diastasis- second- slower
atrial systole- final- atria contract
isovolumetric contraction is what
atria repolarize,
ventricles depolarize
AV valves close
Heart sound S1 occurs
ventricular ejection
semilunar valves open
pressure peaks in left ventricle at 120 mmHg and 25 mmHg in right
T wave occurs in this phase
ventricular ejection lasts about how long
200 to 250 ms
stroke volume is about
70 mL
isovolumetric relaxation
ventricles begin to expand
semilunar valves close
S2 heart sounds happen
in a resting person atrial systole last about
0.1 second
in a resting person ventricular systole lasts about
0.3 second
quiescent period is what
when all four chambers are in diastole
lasts about 0.4 second
in a resting person the cardiac cycle’s resting heart rate is what
75 bpm
end-systolic volume is what
60 mL
systolic volume is added to ventricle during atrial diastole is
+30 mL
added by atrial systole
+40 mL
total end diastolic volume is what
130 MI
stoke volume ejected by ventricular systole is what
-70 mL
congestive heart failure is what
failure of either ventricle to eject blood effectively
left ventricular failure is what
blood backs up into the lungs causing pulmonary edema(shortness of breath)
right ventricular failure is what
blood backs up in the vena cava causing systemic adema
cardioacceleratory center sends sympathetic innervation through?
cardiac nerves
cardioinhibitory center sends parasympathetic innervation through?
vagus nerve