Cardiac Anatomy & Physiology Flashcards

Which structure in the fetal heart allows blood to bypass the lungs by connecting the pulmonary artery to the aorta?

Answer: Ductus arteriosus

The ductus arteriosus is a fetal shunt connecting the pulmonary artery to the descending aorta, diverting blood away from the non-functioning lungs.

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

Answer: Volume of blood in the ventricle at end-diastole

Preload refers to the volume of blood filling the ventricle at end-diastole (end-diastolic volume), which stretches the myocardial fibers before contraction.

Which ECG waveform is absent in atrial fibrillation?

Answer: P wave

In atrial fibrillation, the organized atrial depolarization that produces distinct P waves is replaced by chaotic fibrillatory waves.

The left anterior descending (LAD) artery primarily supplies which area of the heart?

Answer: Anterior wall of the left ventricle and anterior septum

The LAD artery supplies the anterior wall of the left ventricle, the anterior two-thirds of the interventricular septum, and the apex.

Which cardiac valve has only two leaflets (cusps)?

Answer: Mitral valve

The mitral (bicuspid) valve has only two leaflets — the anterior and posterior cusps — unlike the tri-leaflet aortic, pulmonic, and tricuspid valves.

Starling's Law of the Heart states that increased ventricular filling leads to:

Answer: Increased stroke volume due to greater myocardial stretch

Frank-Starling's Law states that the heart contracts more forcefully when its muscle fibers are stretched by greater preload, increasing stroke volume.

Which layer of the pericardium directly contacts the epicardium of the heart?

Answer: Visceral pericardium

The visceral pericardium (epicardium) is the innermost serous layer that directly covers the myocardium and is considered part of the heart wall.