Cardiac output is normally expressed as
liters per minute.
The sinoatrial (SA) node is referred to as the _____________ of the heart.
pacemaket
When blood is flowing out of the left ventricle, the bicuspid valve
is __________ and the aortic semilunar
valve is __________.
closed/ open
Excess potassium ions in cardiac tissue will cause the heart rate and stroke volume to
decrease
Coronary arteries are _____ when all four heart chambers are relaxed.
patent (open)
During which event of the cardiac cycle are all four valves closed while both the atria and ventricles relax?
isovolumetric relaxation
Because the ventricular myocardium is compressed during ventricular _______, most coronary flow occurs during ventricular _______.
contraction/ relaxation
What variables determine the effects on cardiac output?
changes in both HR and SV
Without a plateau extending the refractory period in cardiac muscle, sarcomeres might be stimulated so quickly that they would contract and not relax and instead would experience a sustained contraction, also called
tetany
Oxygenated blood flows from the __________ to the __________ before being pumped into the systemic circulation.
left atrium; left ventricle
Which of the following does not contribute to the ability of cardiac muscle to meet it's energy demands?
Glycolytic enzymes
What is the correct order of spread of the action potential through the heart's conduction system?
SA node, AV node, AV bundle, Purkinje fibers/cell gap junctions
During which event of the cardiac cycle do the atria both relax and contract?
Ventricular filling
Referred pain, often down the left shoulder and arm, in response to myocardial ischemia is called
angina pectoris.
What is the correct order of mechanical events associated with cardiac muscle contraction?
Calcium entry into the sarcoplasm, calcium binds to troponin, muscle contracts, closing of calcium channels, calcium released from troponin, muscle relaxes
Given that cardiac output equals ____________, there are only two ways to change it: change the heart rate or change the stroke volume.
HR X SV