Cardiovascular System: Heart Anatomy, Physiology, and Cardiodynamics

A complete set of vocabulary flashcards covering heart anatomy, histology, conducting system, ECG features, cardiac cycle phases, cardiodynamics formulas, and autonomic innervation.

Pulmonary Circuit

The blood vessel circuit that carries blood to and from the gas exchange surfaces of the lungs.

Systemic Circuit

The blood vessel circuit that carries blood to and from the body tissues.

Arteries

Blood vessels that carry blood away from the heart.

Veins

Blood vessels that carry blood toward the heart.

Capillaries

Microscopic exchange vessels located between arteries and veins that exchange dissolved gases, nutrients, and wastes between blood and tissues.

Right Atrium

Heart chamber that collects oxygen-poor blood from the systemic circuit.

Right Ventricle

Heart chamber that pumps oxygen-poor blood into the pulmonary circuit.

Left Atrium

Heart chamber that collects oxygen-rich blood from the pulmonary circuit.

Left Ventricle

Heart chamber that pumps oxygen-rich blood into the systemic circuit.

Base of the Heart

The broad superior region of the heart attached to the great veins and arteries.

Apex of the Heart

The pointed tip located at the inferior end of the heart.

Parietal Pericardium

The outer layer of the serous pericardium that forms the inner lining of the pericardial sac.

Visceral Pericardium

The inner layer of the serous pericardium that directly covers the surface of the heart, also known as the epicardium.

Pericardial Cavity

The fluid-filled space situated between the parietal and visceral layers of the pericardium containing pericardial fluid.

Pericardial Sac

A fibrous tissue structure that surrounds and stabilizes the heart within the mediastinum.

Auricle

An expandable outer flap or pouch on the surface of an atrium.

Coronary Sulcus

A deep surface groove on the heart that marks the boundary separating the atria from the ventricles.

Anterior Interventricular Sulcus

A groove on the anterior surface of the heart separating the left and right ventricles, housing blood vessels supplying cardiac muscle.

Epicardium

The outer layer of the heart wall formed by the visceral pericardium.

Myocardium

The middle muscular layer of the heart wall composed of concentric layers of cardiac muscle tissue.

Endocardium

The innermost layer of the heart wall lined by simple squamous epithelium (endothelium) and loose connective tissue.

Intercalated Discs

Specialized cell-to-cell junctions in cardiac muscle tissue secured by desmosomes and linked by gap junctions to convey contractile forces and propagate action potentials.

Interatrial Septum

The internal muscular partition that separates the right atrium from the left atrium.

Interventricular Septum

The thick internal partition that separates the right ventricle from the left ventricle.

Superior Vena Cava

A large vein returning blood to the right atrium from the head, neck, upper limbs, and chest.

Inferior Vena Cava

A large vein returning blood to the right atrium from the trunk, viscera, and lower limbs.

Coronary Sinus

A large venous channel on the posterior surface of the heart into which cardiac veins return blood before opening into the right atrium.

Right Atrioventricular (AV) Valve

Also known as the tricuspid valve; a valve with three cusps located between the right atrium and right ventricle that prevents backflow into the atrium.

Left Atrioventricular (AV) Valve

Also known as the bicuspid valve or mitral valve; a valve with two cusps situated between the left atrium and left ventricle.

Chordae Tendineae

Tendinous fibrous cords attaching the free edges of AV valve cusps to papillary muscles, preventing valves from opening backward into the atria.

Papillary Muscles

Muscular projections on the internal ventricular walls connected to chordae tendineae that contract to maintain valve cusp tension.

Semilunar Valves

The pulmonary and aortic valves, each containing three tripod-like cusps without muscular support, that prevent backflow from the pulmonary trunk and aorta into the ventricles.

Aortic Sinuses

Sac-like dilations at the base of the ascending aorta that prevent valve cusps from sticking to the aortic wall and give origin to the left and right coronary arteries.

Sectional Anatomy of the Heart

Diagram illustrating internal structures including chambers, septa, atrioventricular valves, semilunar valves, chordae tendineae, and papillary muscles.

Cardiac Skeleton

A network of four dense fibrous tissue bands surrounding the heart valves and bases of the aorta and pulmonary trunk that physically supports muscle fibers, stabilizes valves, and electrically insulates ventricular cells from atrial cells.

Coronary Circulation (Anterior View)

Anatomy of blood vessels supplying the heart muscle on its anterior surface, including the right coronary artery, left coronary artery, circumflex artery, anterior interventricular artery, and great cardiac vein.

Right Coronary Artery (RCA)

Coronary artery originating at the aortic sinus that supplies blood to the right atrium, portions of both ventricles, SA and AV nodes, marginal arteries, and posterior interventricular artery.

Left Coronary Artery (LCA)

Coronary artery originating at the aortic sinus that divides into the circumflex artery and anterior interventricular artery to supply the left ventricle, left atrium, and interventricular septum.

Arterial Anastomoses

Interconnections between the anterior and posterior interventricular arteries that stabilize blood supply to the myocardium.

Great Cardiac Vein

A cardiac vein that drains blood from the region supplied by the anterior interventricular artery and empties into the coronary sinus.

Contractile Cells

Cardiac muscle cells that produce contractions propelling blood through the cardiovascular system.

Conducting System of the Heart

A specialized network of cardiac muscle cells including the SA node, AV node, AV bundle, bundle branches, and Purkinje fibers that initiates and distributes electrical impulses to coordinate heartbeats.

Automaticity

The intrinsic property of cardiac muscle tissue to generate electrical impulses and contract automatically without neural stimulation.

Cardiac Muscle Action Potential Phases

The electrical profile of cardiac muscle cells comprising Rapid Depolarization ($Na^+$ entry, $3\text{--}5\,msec$), Plateau ($Ca^{2+}$ entry, $\sim 175\,msec$), and Repolarization ($K^+$ loss, $75\,msec$).

Sinoatrial (SA) Node

The natural pacemaker tissue located in the wall of the right atrium that generates $70\text{--}80$ action potentials per minute.

Atrioventricular (AV) Node

Conducting node located at the junction between atria and ventricles generating $40\text{--}60$ action potentials per minute, introducing a $100\,msec$ delay to allow atrial contraction to complete.

Purkinje Fibers

Conduction fibers that distribute electrical impulses throughout the ventricular myocardium to trigger ventricular contraction.

Bradycardia

An abnormally slow heart rate.

Tachycardia

An abnormally fast heart rate.

Ectopic Pacemaker

Abnormal cardiac cells generating action potentials at a high rate that bypass the conducting system and disrupt ventricular contractions.

Electrocardiogram (ECG / EKG)

A recording of electrical events in the heart obtained by placing electrodes at specific body locations, featuring P wave, QRS complex, and T wave.

P Wave

The ECG deflection corresponding to atrial depolarization.

QRS Complex

The ECG deflection corresponding to ventricular depolarization.

T Wave

The ECG wave corresponding to ventricular repolarization.

Cardiac Cycle

The sequence of events occurring between the start of one heartbeat and the beginning of the next, encompassing atrial and ventricular systole and diastole.

Systole

The contraction phase of a heart chamber during the cardiac cycle, accompanied by rising blood pressure.

Diastole

The relaxation phase of a heart chamber during the cardiac cycle, accompanied by falling blood pressure.

First Heart Sound (S1)

Loud heart sound produced by the closure of the atrioventricular (AV) valves at the onset of ventricular systole.

Second Heart Sound (S2)

Loud heart sound produced by the closure of the semilunar valves at the onset of ventricular diastole.

Cardiac Output (CO)

The total volume of blood pumped by the left ventricle per minute, defined by the formula $CO = HR \times SV$.

Stroke Volume (SV)

The volume of blood ejected by a ventricle during a single contraction, measured in $\text{mL/beat}$.

Bainbridge Reflex

Also known as the atrial reflex; an automatic reflex that adjusts heart rate in response to venous return, mediated by stretch receptors in the right atrium that increase sympathetic activity.

Autonomic Innervation of Heart

Neural regulation of the heart involving the cardioinhibitory and cardioacceleratory centers in the medulla oblongata, vagus nerve (N X), and sympathetic ganglia.

Cardioacceleratory Center

A center in the medulla oblongata that controls sympathetic neurons to increase heart rate and force of contraction.

Cardioinhibitory Center

A center in the medulla oblongata that controls parasympathetic neurons via vagus nerves (N X) to reduce heart rate.