Question

question 10
the four structures that compose the conduction system of the heart are the
sa node, av node, av bundle, and purkinje fibers.
sa node, av node, av bundle, and chordae tendinae.
av node, av bundle, purkinje fibers, and chordae tendinae.
sa node, av node, av bundle, and papillary muscles.
question 11
a graphic record of the hearts electrical activity is a(n)
ecg.
eeg.
cat scan.
mri.
question 12
mechanical devices that permit the flow of blood in one direction only are called
ventricles.
atria.
valves.
vessels.

Explanation:

• Question 10: The conduction system of the heart starts with the SA (sino - atrial) node which initiates the electrical impulse. The impulse then goes to the AV (atrio - ventricular) node, then to the AV bundle (bundle of His), and finally to the Purkinje fibers. Chordae tendineae and papillary muscles are related to the heart valves (preventing valve prolapse) and not part of the conduction system.
• Question 11: An ECG (electrocardiogram) records the heart's electrical activity. An EEG (electroencephalogram) records the brain's electrical activity. A CAT scan (computerized axial tomography) and MRI (magnetic resonance imaging) are imaging techniques that do not specifically record electrical activity (CAT scan uses X - rays and MRI uses magnetic fields and radio waves for anatomical imaging).
• Question 12: Valves (such as the mitral, tricuspid, aortic, and pulmonary valves) in the heart and blood vessels ensure unidirectional blood flow. Ventricles are chambers of the heart that pump blood. Atria are the upper chambers of the heart that receive blood. Vessels are the tubes (arteries, veins, capillaries) through which blood flows.

Answer:

• Question 10: SA node, AV node, AV bundle, and Purkinje fibers.
• Question 11: ECG.
• Question 12: valves.