Cardiac Anatomy & Physiology Flashcards

During isovolumetric contraction, which of the following best describes the state of the heart valves?

Answer: All valves closed

During isovolumetric contraction, all four valves are closed as ventricular pressure rises but has not yet exceeded aortic or pulmonary pressure to open semilunar valves.

The left circumflex artery (LCx) most commonly supplies which region of the heart?

Answer: Lateral wall of the left ventricle

The left circumflex artery runs in the left atrioventricular groove and primarily supplies the lateral wall of the left ventricle and the left atrium.

What does the term 'preload' refer to in cardiac physiology?

Answer: Ventricular wall tension at end-diastole

Preload refers to the ventricular wall tension (stretch) at end-diastole, which is determined by end-diastolic volume and reflects the degree of myocardial fiber stretch before contraction.

Which structure separates the right and left ventricles?

Answer: Interventricular septum

The interventricular septum is a thick muscular wall that divides the left and right ventricles and contributes significantly to left ventricular pumping function.

What is the primary pacemaker of the heart under normal conditions?

Answer: Sinoatrial (SA) node

The SA node, located in the right atrium near the superior vena cava, spontaneously depolarizes at the fastest intrinsic rate (~60–100 bpm) and serves as the heart's primary pacemaker.

Which great vessel carries deoxygenated blood from the right ventricle to the lungs?

Answer: Pulmonary artery

The pulmonary artery (and its right and left branches) carries deoxygenated blood from the right ventricle to the lungs for oxygenation.

Starling's Law of the Heart states that stroke volume increases when:

Answer: End-diastolic volume increases

Frank-Starling's law states that within physiologic limits, increased ventricular filling (end-diastolic volume) stretches the myocardium and increases stroke volume due to enhanced actin-myosin overlap.