The O wave of an ECG corresponds to
the depolarization of the atria
In order for blood to enter the heart
the atria must not only be at rest but the atrial pressure must be lower than the veins
Atrial contraction
begins during the latter part of the P wave
During the isovolumic phase of ventricular systole
the atrioventricular valves and semilunar valves are closed
According to Starling's law of the heart, the cardiac output is directly related to the
venous return
Each of the following changes will result in increased blood flow to a tissue except one. Ideneityf the exception
A increased blood pressure
B relaxation of precapillary sphincters
C increased blood volume
D decreased peripheral resistance
E decreased ves
decreased vessel diameter
The AV node is important because it
delays the transmission of the electrical impulses to the ventricles in order for the atria to finish contracting
Autorhythmic cells
are also called pacemakers because they set the rate of the heartbeat
What type of tissue, present in the walls of blood vessels, allows for regulation of vessel diameter
smooth muscle
Which two mechanisms influence the force of cardiac contraction
End diastolic volume and sympathetic nervous system stimulation
Mean arterial pressure is equal to diastolic pressure plus one-third of the pulse pressure. An equivalent equation is MAP= 2/3DBP+1/3 SBP. Why is diastolic blood pressure (DBP) a larger component of MAP than systolic blood pressure (SBP)
The heart spends more time in diastole than systole
Which set of changes correctly describes the baroreceptor reflex in response to increased blood pressure?
A Decreased vessel diameter, decreased resistance, decreased cardiac output
B Increased vessel diameter, decreased resistance, decreased cardiac outp
B
Blood flow to a tissue will increase if the
level of carbon dioxide at the tissue increases
The mean arterial pressure (MAP) is important because
it represents the driving pressure for blood flow.
The inner lining of blood vessels is called
endothelium.