Cardiovascular System Flashcards
7 cards from real Anatomy and Physiology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Cardiovascular System flashcards as text
On an electrocardiogram (ECG), the P wave represents:
Answer: Atrial depolarization
The P wave reflects electrical depolarization spreading through the atria from the SA node, triggering atrial contraction.
During which phase of the cardiac cycle do the ventricles primarily fill with blood?
Answer: Diastole
During diastole, the ventricles relax and AV valves open, allowing blood to flow from the atria into the ventricles.
Cardiac output is calculated by multiplying:
Answer: Heart rate × stroke volume
Cardiac output (CO) = Heart rate (HR) × Stroke volume (SV), representing the volume of blood pumped by the heart per minute.
The Frank-Starling law of the heart states that:
Answer: The heart contracts more forcefully as ventricular filling (preload) increases
The Frank-Starling law describes how greater ventricular filling stretches cardiac muscle fibers, resulting in a more forceful contraction and larger stroke volume.
Which ion plays the primary role in triggering cardiac muscle contraction?
Answer: Calcium (Ca2+)
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.
The refractory period of cardiac muscle is important because it prevents:
Answer: Tetanic (sustained) contractions that would stop effective pumping
The long refractory period of cardiac muscle ensures complete relaxation between contractions, preventing sustained tetanic contractions that would prevent the heart from filling and pumping.
Which component of the cardiac conduction system is responsible for delaying the electrical signal between the atria and ventricles?
Answer: Atrioventricular (AV) node
The AV node introduces a brief conduction delay (~0.1 second) that allows the atria to finish contracting and the ventricles to fill before ventricular contraction begins.