Quiz 3 (cardiovascular physiology and auscultation of Heart sounds) Flashcards
….. of the heart means “to listen to” and study the various sounds arising from the heart duirng its pumping activity
Auscultation
heart sounds may be heard by placing your ear on the chest or by using a…
stethoscope
the vibrations producing the sounds can be visually displayed through the use of a heart sound microphone and physiological recorder to produce a
Phonocardiogram
- produced at the beginning of systole when the atrioventricular (A-V) valves
close and the semilunar (S-L) valves open. This has a lower pitched tone commonly termed
the “lub” sound of the heartbeat.
1st heart sound
occurs during the end of systole and is produced by the closure of the S-L
valves, the opening of the A-V valves, and the resulting vibrations in the arteries and
ventricles. Due to the higher blood pressures in the arteries the sound produced is higher
pitched. It is commonly referred to as the “dub” sound
2nd heart sound
occurs during the rapid filling of the ventricles after the A-V valves open
and is probably produced by vibrations of the ventricular walls.
3rd heart sound
occurs at the time of atrial contraction and is probably due to the
accelerated rush of blood into the ventricles.
4th Heart sound
the pressure exerted by the blood against
the vessel walls, the arterial blood pressure being the most frequently measured pressure and the most
useful
blood pressure
: the highest pressure in the artery–produced during the heart’s
contraction (systolic) phase. Normal for a 20-year-old male is 120mm Hg.
Systolic Blood Pressure:
the lowest pressure in the artery–produced during the heart’s
relaxation (diastolic) phase. Normal for a 20-year-old male is 80mm Hg
Diastolic Blood Pressure:
the difference between the systolic and diastolic pressures. Normal value is
40mm Hg.
- Pulse Pressure:
Diastolic pressure + 1/3 of the pulse pressure. This is the average effective
pressure forcing blood through the circulatory system. Normal value is 96-100mm Hg
Mean Blood Pressure:
The mean blood pressure is a function of two factors
cardiac output (CO), the amount of blood pumped out of the left ventricle per unit of time, and total peripheral resistance (TPR):
Equation of mean B.P
Mean B.P (mm Hg) = cardiac output (ml/min) x total peripheral resistance (TPR units)
Equation of cardiac output
cardiac output (ml/min) = heart rate (beats/min) x stroke volume (ml/beat)
Peripheral resistance depends on…
the caliber (diameter) of the blood vessels and the viscosity of the blood.
Any factor that increases either the cardiac output or the total peripheral resistance causes….
an almost
immediate reflex rise in blood pressure
the force of
contraction of the heart
systolic B.P.
the condition of the systemic blood vessels
diastolic pressure
an increase in the diastolic pressure indicates a….
decrease in vessel elasticity
a cannula is
inserted into the artery and the direct, head-on pressure of the blood is measured with a transducer or
mercury manometer.
direct method