CARLA 13
Which of the following is true regarding cardiac muscle? 1) Neither summation or tetany can occur 2) Both summation and tetany can occur 3) Summation, but not tetany, can occur 4) Tetany, but not summation, can occur 5) None of these are true
1) Neither summation or tetany can occur
Which of the following is longer? 1) the refractory period of cardiac muscle 2) the refractory period of skeletal muscle
1) the refractory period of cardiac muscle
In which situation would the stroke volume be the greatest? 1) when venous return is increased 2) when venous return is decreased 3) when calcium channel blockers are present 4) when the difference between the end diastolic volume and the systolic volume is small 5) when the force of contraction is decreased
1) when venous return is increased
Each of the following factors will increase cardiac output except one. Identify the exception 1) increased venous return 2) increased parasympathetic stimulation 3) increased force of ventricular contraction 4) increased heart rate 5) increased sympathetic stimulation
2) increased parasympathetic stimulation
The following are various component of the conducting system of the heart 1) Purkinje cells 2) AV bundle 3) AV node 4) SA node 5) Bundle branches the sequence in which an action potential would move through the system is
4,3,2,5,1
Depolarization of the ventricles is represented on the electrocardiogram by the
QRS complex
The pacemaker cells of the heart are located in the___
SA node
The P wave of the ECG corresponds to
atrial depolarization
The heart is innervated by
both parasympathetic and sympathetic nerves
Under conditions of hypercalcemia
cardiac muscles become extremely excitable
The function of an atrium is to
collect blood
The left and right pulmonary veins carry blood to the___
heart
Blood returning from the systemic circuit first enters the
right atrium
The volume of blood ejected from each ventricle during a contraction is called the___
stroke volume
The cardioacceleratory center in the medulla oblongata activates ____ neurons
sympathetic
As a result of the long refractory period, cardiac muscle cannot exhibit
tetany
The first heart sound is heard when
the AV valves close
The left ventricle pumps blood to
the systemic circuit
According to Starling's Law of the heart, the cardiac output is directly related to...
the venous return
Relaxation of the ventricles is called
ventricular diastole
