Anatomy and Function of the Heart (Chapter 11 part 1)

A set of 50 vocabulary flashcards covering cardiac anatomical structures, tissue layers, chambers, valves, systemic and pulmonary pathways, coronary blood flow, and associated clinical correlations.

Mediastinum

The central anatomical compartment of the thoracic cavity situated between the right and left lungs where the heart is located.

Apex of the Heart

The pointed inferior end of the heart that tilts anteriorly toward the left fifth intercostal space.

Base of the Heart

The broad superior aspect of the heart where the great blood vessels attach.

Pericardium

The double-walled fibroserous sac that encloses and protects the heart within the mediastinum.

Fibrous Pericardium

The tough, superficial layer of the pericardial sac that anchors the heart, prevents overfilling, and shields it from trauma.

Parietal Pericardium

The serous membrane lining the inner surface of the outer fibrous pericardium, adhering securely to chest wall structures.

Visceral Pericardium (Epicardium)

The smooth serous membrane that forms the external surface of the heart, containing coronary blood vessels and adipose padding.

Pericardial Cavity

A potential space between the parietal and visceral pericardial layers containing lubricating serous fluid that eliminates friction during cardiac contraction.

Pericarditis

Inflammation of the pericardium that roughens the membrane surfaces, producing a characteristic auscultatory pericardial friction rub.

Cardiac Tamponade

Compression of the heart chambers resulting from excess inflammatory exudate accumulating within the rigid pericardial cavity, severely restricting ventricular diastolic filling.

Myocardium

The thick muscular middle layer forming the bulk of the heart wall that contracts forcefully to propel blood.

Endocardium

A glistening endothelial sheet composed of simple squamous epithelium resting on connective tissue that lines the internal heart chambers and covers cardiac valves.

Cardiomyocytes

Short, branched, striated, uninucleate cardiac muscle cells arranged in spiral bundles around the heart chambers.

Intercalated Disks

Dense specialized cellular junctions connecting the ends of adjacent cardiomyocytes.

Desmosomes

Mechanical anchoring junctions within intercalated disks that prevent cardiac muscle cells from pulling apart during forceful contraction.

Gap Junctions

Protein channels located in intercalated disks that facilitate rapid ion exchange between cardiomyocytes, enabling electrical coupling.

Functional Syncytium

The property of the myocardium to contract synchronously as a single coordinated unit due to ion transfer across gap junctions.

Auricle

A wrinkled, dog-ear-shaped expandable muscular pouch protruding externally from each atrium that expands to hold excess venous blood volume.

Atrial Natriuretic Peptide (ANP)

A hormone secreted by specialized atrial myocytes upon atrial stretch that stimulates the kidneys to excrete sodium and water, reducing blood pressure.

Right Atrium

The chamber of the heart that receives deoxygenated blood returning from systemic tissues via the superior vena cava, inferior vena cava, and coronary sinus.

Left Atrium

The chamber of the heart that receives freshly oxygenated blood returning from pulmonary circulation through four pulmonary veins.

Right Ventricle

The chamber with a wall thickness of $4\text{--}5\,\text{mm}$ that pumps deoxygenated blood through the pulmonary trunk into the low-resistance pulmonary capillary bed.

Left Ventricle

The thickest-walled heart chamber ($12\text{--}15\,\text{mm}$, approximately $3\times$ thicker than the right ventricle) that ejects oxygenated blood into the aorta against systemic vascular resistance.

Interatrial Septum

The internal cardiac wall separating the right atrium from the left atrium.

Fossa Ovalis

A shallow depression on the interatrial septum representing the closed remnant of the embryonic foramen ovale.

Interventricular Septum

The thick muscular internal wall separating the right and left ventricles that contributes significantly to overall pumping force.

Septal Defect

An abnormal cardiac opening in an internal septum that shunts blood from the high-pressure left heart into the right heart, elevating pulmonary pressure.

Atrioventricular (AV) Valves

Valves positioned between the atria and ventricles that enforce unidirectional blood flow by preventing backflow into the atria during ventricular systole.

Tricuspid Valve

The atrioventricular valve composed of three flexible cusps situated between the right atrium and the right ventricle.

Bicuspid (Mitral) Valve

The heavy-duty atrioventricular valve composed of two cusps situated between the left atrium and the left ventricle.

Chordae Tendineae

Tough collagenous cords, known as heart strings, connecting the free edges of atrioventricular valve cusps to papillary muscles.

Papillary Muscles

Muscular projections of the ventricular myocardium that contract during systole to pull chordae tendineae taut, preventing AV valve prolapse into the atria.

Pulmonary Semilunar Valve

A three-cusped valve guarding the orifice at the base of the pulmonary trunk, opening as the right ventricle ejects blood toward the lungs.

Aortic Semilunar Valve

A three-cusped valve guarding the exit of the left ventricle into the ascending aorta, closing tightly during diastole when arterial backpressure fills its crescent cusps.

Mitral Stenosis

Narrowing and fusion of the bicuspid valve leaflets, often due to rheumatic fever, which restricts diastolic flow from the left atrium into the left ventricle.

Diastolic Rumbling Murmur

The characteristic low-pitched heart murmur heard at the cardiac apex that indicates mitral stenosis.

Pulmonary Circuit

The low-pressure circulatory pathway driven by the right heart that transports deoxygenated blood to alveolar capillary beds for gas exchange and returns oxygenated blood to the left atrium.

Systemic Circuit

The high-pressure circulatory pathway driven by the left heart that supplies oxygenated blood to all peripheral organs and tissues of the body.

Superior Vena Cava

A large systemic vein that delivers deoxygenated blood returning from body regions superior to the diaphragm directly into the right atrium.

Inferior Vena Cava

A large systemic vein that delivers deoxygenated blood returning from body regions inferior to the diaphragm into the right atrium.

Pulmonary Trunk

The great arterial trunk departing from the right ventricle that bifurcates into pulmonary arteries leading to the lungs.

Pulmonary Veins

Four vessels entering the posterior left atrium that deliver oxygenated blood from the pulmonary capillary beds.

Aorta

The main arterial trunk exiting the left ventricle that distributes oxygenated blood to the systemic circulation.

Aortic Sinuses (Sinuses of Valsalva)

Anatomical pockets located in the aorta immediately superior to the aortic semilunar valve cusps that give origin to the coronary arteries.

Right Coronary Artery (RCA)

A major branch of the ascending aorta traveling along the coronary sulcus, giving rise to the right marginal branch and posterior interventricular artery.

Left Coronary Artery (LCA)

A major branch of the ascending aorta that bifurcates into the circumflex artery and the left anterior descending artery.

Left Anterior Descending (LAD) Artery

A branch of the left coronary artery that courses down the anterior interventricular sulcus to supply the anterior ventricular walls and interventricular septum.

Coronary Sinus

A broad, thin-walled venous vessel on the posterior coronary sulcus that collects blood from cardiac veins and empties directly into the right atrium.

Myocardial Ischemia

A pathologic state of inadequate arterial blood flow to the heart wall that starves cardiomyocytes of essential oxygen and glucose.

Athlete's Heart

Beneficial physiological cardiac hypertrophy resulting from endurance conditioning, marked by chamber enlargement, enhanced stroke volume, and resting bradycardia ($<60\,\text{bpm}$).