Anatomy and Physiology Cardiovascular System 3

Question 1

On an electrocardiogram (ECG), the P wave represents:

Accepted Answer

Atrial depolarization

Answer

The P wave reflects electrical depolarization spreading through the atria from the SA node, triggering atrial contraction.

Question 2

During which phase of the cardiac cycle do the ventricles primarily fill with blood?

Accepted Answer

Diastole

Answer

During diastole, the ventricles relax and AV valves open, allowing blood to flow from the atria into the ventricles.

Question 3

Cardiac output is calculated by multiplying:

Accepted Answer

Heart rate × stroke volume

Answer

Cardiac output (CO) = Heart rate (HR) × Stroke volume (SV), representing the volume of blood pumped by the heart per minute.

Question 4

The Frank-Starling law of the heart states that:

Accepted Answer

The heart contracts more forcefully as ventricular filling (preload) increases

Answer

The Frank-Starling law describes how greater ventricular filling stretches cardiac muscle fibers, resulting in a more forceful contraction and larger stroke volume.

Question 5

Which ion plays the primary role in triggering cardiac muscle contraction?

Accepted Answer

Calcium (Ca2+)

Answer

Calcium ions (Ca2+) enter cardiac muscle cells during the plateau phase of the action potential and bind to troponin, initiating the cross-bridge cycling that produces contraction.

Anatomy and Physiology Practice Test

Anatomy and Physiology Practice Test

Anatomy and Physiology Cardiovascular System 3