Cardiac Anatomy and Physiology Flashcards

Which structure separates the right and left atria and may harbor a patent foramen ovale (PFO) in adults?

Answer: Fossa ovalis

The fossa ovalis is a thin fibromuscular remnant of the foramen ovale in the interatrial septum; incomplete fusion leaves a PFO, present in ~25% of adults.

Cardiac output is calculated as:

Answer: Heart rate × stroke volume

Cardiac output (CO) equals heart rate (HR) multiplied by stroke volume (SV), representing the total volume of blood pumped per minute.

Which type of cardiomyocytes has the fastest intrinsic depolarization rate and therefore sets the heart's rhythm?

Answer: Sinoatrial nodal cells

SA nodal cells depolarize spontaneously at 60–100 times per minute, the fastest of all pacemaker cells, making them the dominant cardiac pacemaker.

Which valve is bicuspid (has two leaflets)?

Answer: Mitral valve

The mitral (bicuspid) valve has two leaflets — the anterior and posterior — and guards the left atrioventricular orifice.

The aortic valve opens when left ventricular pressure exceeds:

Answer: Aortic diastolic pressure

The aortic valve opens once rising LV systolic pressure surpasses aortic diastolic pressure (approximately 80 mmHg at rest), allowing blood ejection into the aorta.

Which portion of the interventricular septum is thinnest and most commonly involved in membranous ventricular septal defects?

Answer: Membranous septum

The membranous septum is the small fibrous upper portion of the interventricular septum and is the most common site for congenital ventricular septal defects.

During diastole, the left ventricle fills primarily due to which mechanism in early diastole?

Answer: Ventricular suction from elastic recoil

Early diastolic LV filling is driven largely by active ventricular relaxation (lusitropy) and elastic recoil, creating a suction effect that draws blood from the left atrium.