Cardiovascular Anatomy and Physiology Flashcards

The bundle of His divides into the right and left bundle branches at which anatomical location?

Answer: Top of the interventricular septum, just below the membranous septum

After passing through the AV node, the impulse travels through the bundle of His, which divides into the right and left bundle branches at the upper muscular portion of the interventricular septum.

Which chambers of the heart are separated by the interatrial septum?

Answer: Right atrium and left atrium

The interatrial septum is the wall that separates the two atria. It contains the fossa ovalis, a remnant of the foramen ovale from fetal circulation.

What is the Frank-Starling law of the heart?

Answer: The strength of ventricular contraction increases as preload (end-diastolic volume) increases, up to a physiologic limit

The Frank-Starling law states that within physiologic limits, the heart contracts more forcefully when it is filled with more blood — greater stretch of the myocardial fibers results in stronger contraction.

Which valve separates the left atrium from the left ventricle?

Answer: Mitral (bicuspid) valve

The mitral valve (also called the bicuspid valve because it has two leaflets) is located between the left atrium and left ventricle, controlling blood flow during the cardiac cycle.

Blood returning from the lungs enters the heart through which structure?

Answer: Pulmonary veins into the left atrium

Oxygenated blood from the lungs returns to the heart via four pulmonary veins that drain into the left atrium, completing the pulmonary circulation circuit.

What is the approximate duration of the normal PR interval and what does it represent?

Answer: 0.12-0.20 seconds; conduction time from SA node through the atria and AV node to the ventricles

The normal PR interval is 0.12-0.20 seconds (3-5 small squares) and represents the time for the electrical impulse to travel from the SA node through the atria and be delayed in the AV node before reaching the ventricles.