2. Functional Anatomy of the Heart

Flashcards covering functional anatomy of the heart.

Right Atrium

Receives deoxygenated systemic blood primarily via the cranial and caudal venae cavae.

Right Ventricle

Fills passively with blood from the right atrium through the open right AV valve; contracts to send blood through the pulmonary valve, into the pulmonary trunk, and to the lungs.

Pulmonary Valve

Opens when the right ventricle contracts, allowing blood to flow into the pulmonary trunk; closes when the right ventricle relaxes to prevent backflow.

Left Atrium

Receives oxygenated blood from the lungs via the pulmonary veins.

Left Ventricle

Fills with blood from the left atrium through the open left AV valve; contracts to send blood through the aortic valve and into the aorta.

Aortic Valve

Opens when the left ventricle contracts, allowing blood to flow into the aorta; closes when the left ventricle relaxes to prevent backflow.

Atrial Systole

Simultaneous contraction of both atria.

Ventricular Systole

Simultaneous contraction of both ventricles.

Diastole

Simultaneous relaxation of all four heart chambers.

First Heart Sound (Lubb)

Occurs during ventricular systole and is caused by the AV valves snapping shut.

Second Heart Sound (Dup)

Heard during diastole and is caused by the closure of the pulmonary and aortic valves.

Pulmonary Valve Auscultation (P of PAM)

Heard in the third intercostal space at the level of the costochondral junction on the left side.

Aortic Valve Auscultation (A of PAM)

Heard in the fourth intercostal space just below the level of the shoulder joint on the left side.

Left AV (Mitral) Valve Auscultation (M of PAM)

Heard in the fourth or fifth intercostal space just above the costochondral junction on the left side.

Right Atrioventricular Valve Auscultation

Heard at the third or fourth intercostal space at the costochondral junction on the right side.

SA Node

The pacemaker of the heart, located in the right atrial myocardium near the junction with the cranial vena cava. Has the highest rate of inherent rhythmicity.

AV Node

Located in the right ventral region of the interatrial septum, just above the entry of the coronary sinus; delays spread of depolarization until atrial systole is complete. Innervated by left vagus nerve.

AV Bundle

Specialized fibers that penetrate the fibrous skeleton of the heart, allowing electrical stimuli to pass from the atria to the ventricles.

Purkinje Fibers

Fibers that spread out through the ventricular myocardium from the apex, aiding in coordinated and rapid spread of electrical impulses to the ventricles.

Trabeculae Septomarginalis

Carry Purkinje fibers to aid coordinated and rapid spread of electrical impulses to the ventricles.

Cardiac Plexus

Formed by sympathetic and parasympathetic branches of cardiac nerves, located ventral to the bifurcation of the trachea, caudal and lateral to the arch of the aorta, and around the branches of the pulmonary trunk at its bifurcation.

Myogenic

The origin of the heartbeat is muscular.