phys unit 2

The right side of the heart receives: a. oxygenated blood from the systemic circuit. b. deoxygenated blood from the pulmonary circuit. c. deoxygenated blood from the systemic circuit. d. oxygenated blood from the pulmonary circuit.

deoxygenated blood from the systemic circuit.

TRUE OR FALSE. An electrocardiogram recording is the same thing as an action potential.

false

TRUE OR FALSE. Stroke volume (SV) can be calculated by subtracting the end-diastolic volume (EDV) from the end-systolic volume (ESV).

false

true or false. There are two phases of the cardiac cycle in which all four heart valves are open: the isovolumetric contraction phase and the isovolumetric relaxation phase.

false

The rapid influx of calcium ions into pacemaker cells creates a positive membrane potential inside the cell and is responsible for the: a. minimum potential phase. b. repolarization phase. c. full depolarization phase. d. slow initial repolarization phase.

full depolarization phase

Cardiac output is determined by what two variables? a. heart rate and stroke volume b. end-diastolic volume and end-systolic volume c. stroke volume and ejection fraction d. heart rate and ejection fraction e. preload and afterload

heart rate and stroke volume

Which of the following factors determines ventricular filling (preload) a. heart rate and venous return b. the pressure in the aorta and the lungs c. end-diastolic volume and end-systolic volume d. parasympathetic activity of the ventricles e. peripheral resistance and tension

heart rate and venous return

As ventricular systole begins, all four heart valves are closed during the: a. ventricular ejection phase. b. isovolumetric contraction phase. c. isovolumetric relaxation phase. d. ventricular filling phase.

isovolumetric contraction phase.

Which component of an ECG represents atrial depolarization? a. P wave b. P-R interval c. T wave d. Q-T interval e. QRS complex

p wave

During what phase of the action potential will calcium ions enter the contractile cell as potassium ions exit? a. rapid depolarization phase b. initial repolarization phase c. repolarization phase d. plateau phase

plateau phase

Which of the following can be used to measure heart rate? a. R-R interval b. S-T segment c. Q-T interval d. P-R interval

r-r interval

The SA node is innervated by the a. sympathetic nervous system only. b. parasympathetic nervous system only c. somatic nervous system only. d. sympathetic and parasympathetic nervous systems. e. sympathetic, parasympathetic, and somatic nervous systems.

sympathetic and parasympathetic nervous systems

What is the primary function of the AV and semilunar valves? a. to permit blood to flow forward while preventing it from flowing backward b. to keep the right and left sides of the heart separated c. to coordinate the autorhythmic movements of the heart d. to control the speed at which blood enter and leaves the heart e. to coordinate the autorhythmic movements of the heart

to permit blood to flow forward while preventing it from flowing backward

TRUE OR FALSE. The sympathetic nervous system increases cardiac output by increasing both heart rate and stroke volume.

true

true or false. The left ventricle has greater muscle mass than the right ventricle since it pumps against greater resistance.

true

Blood is ejected from the left ventricle once pressure within the a. ventricle is greater than pressure within the aorta. b. ventricle is less than pressure within the aorta. c. ventricle is greater than pressure within the pulmonary artery. d. ventricle is less than pressure within the pulmonary artery. e. muscles of the pulmonary semilunar valve relax.

ventricle is greater than pressure within the aorta.