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Cardiac muscle has more mitochondria and depends less on a continual supply of oxygen than does skeletal muscle
False - Does depend on oxygen
Anastomoses among coronary arterial branches provide collateral routes for blood delivery to the heart muscle
Congestive heart failure means that the pumping efficiency of the heart is depressed so that there is inadequate delivery of blood to body tissues
Chronic release of excess thyroxine can cause a sustained increase in heart rate and a weakened heart
Arterial blood supply to heart muscle is continuous whether the heart is in systole or diastole
False - It's intermittent
The "lub" sounds of the heart are valuable in diagnosis because they provide information about the function of the heart's pulmonary and aortic valves
False - It's the DUB sound
Autonomic regulation of heart rate is via two reflex centers found in the pons
False - It's found in the medulla
The papillary muscles contract after the other ventricular muscles so that they can take up the slack on the chordae tendineae before the full force of ventricular contractions sends blood against the AV valve flaps
False - The AV Flaps are closed
An ECG provides direct information about valve function
False - ECG is a composite of all the action potentials generated by nodal and contractile cells at any given time
As pressure in the aorta rises due to atherosclerosis, more ventricular pressure is required to open the aortic valve
Proxysmal atrial tachycardia is characterized by bursts of atrial contractions with little pause between them
Which of the events below does not occur when the semilunar valves are open?
Ventricles are in diastole
Hemorrhage with a large loss of blood causes_____
a lowering of blood pressure due to chance in cardiac output
The left ventricular wall of the heart is thicker than the right wall in order to ________
pump blood with a greater pressure
The term for pain associated with deficient blood delivery to the heart that may be caused by the transient spasm of coronary arteries is ________
To auscultate the aortic semilunar valve, you would place your stethoscope in the ________
second intercostal space to the right of the sternum
The source of blood carried to capillaries in the myocardium would be the ________
The fact that the left ventricle of the heart is thicker than the right ventricle reveals that it ________
pumps blood against a greater resistance
Which of the following is not an age-related change affecting the heart?
thinning of the valve flaps
If cardiac muscle is deprived of its normal blood supply, damage would primarily result from ________
a decreased delivery of oxygen
If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells _______
tetanic contractions might occur, which would stop the heart's pumping action
If the vagal nerves to the heart were cut, the result would be that ________
the heart rate would increase by about 25 beats per minute
Which of these vessels receives blood during ventricular systole?
both the aorta and pulmonary trunk
When viewing a dissected heart, it is easy to visually discern the right and left ventricles by _______
noticing the thickness of the ventricle walls
Select the correct statement about the heart valves
The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur
Select the correct statement about the function of myocardial cells
The entire heart contracts as a unit or it does not contract at all
Select the correct statement about the structure of the heart wall
The myocardium is the layer of the heart that actually contracts
Compared to skeletal muscle, cardiac muscle ________
has gap junctions that allow it to act as a functional syncytium
During the period of ventricular filling ________
blood flows passively through the atria and the open AV valves into the ventricles
The second heart sound is heard during which phase of the cardiac cycle?
isovolumetric relaxation "DUB"
If we were able to artificially alter the membrane permeability of pacemaker cells so that sodium influx is more rapid, ________
threshold is reached more quickly and heart rate would increase
Select the correct statement about cardiac output
A slow heart rate increases end diastolic volume, stroke volume, and force of contraction
During contraction of heart muscle cells ________
some calcium enters the cell from the extracellular space and triggers the release of larger amounts of calcium from intracellular stores
Isovolumetric contraction ________
refers to the short period during ventricular systole when the ventricles are completely closed chambers
Commotio cordis is heart failure due to a ________
relatively mild blow to the chest that occurs during a vulnerable interval (2 ms) when the heart is repolarizing
The enlarged coronary vessel outside the heart that empties blood into the right atrium is the _____
What structure in the fetal heart allows blood to flow from the right atrium directly to the left atrium?
The ___________ and _____________ valves of the heart have no chordae tendineae attached
Aortic and Pulmonary Semilunar
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