Cardiovascular and Respiratory Systems I - The Human Heart and Vasculature

Vocabulary practice flashcards covering cardiac anatomy, heart chambers, internal landmarks, valves, coronary vasculature, conduction system, clinical ischemic conditions, and vessel histology based on HSC1007 lecture notes.

Human Heart (Embryology and Location)

A 4-chambered fibromuscular pump approximately the size of a fist; it is the $1^{\text{st}}$ organ to develop during the $3^{\text{rd}}$ week of intrauterine life and is located in the middle mediastinum of the thoracic cavity resting on top of the diaphragm.

Pericardium

The fibroserous protective covering of the heart consisting of an outer fibrous pericardium and an inner double-layered serous pericardium (parietal layer and visceral layer/epicardium), separated by a fluid-filled pericardial cavity that minimizes friction.

Posteroanterior (PA) Projection

The standard chest X-ray view where the X-ray beam traverses the patient from posterior to anterior with the chest held against the film detector, avoiding artificial magnification of the anteriorly positioned cardiac silhouette.

Sternocostal (Anterior) Surface

The anterior external surface of the heart oriented toward the sternum and costal cartilages, formed predominantly by the right ventricle, along with portions of the right atrium and left ventricle.

Diaphragmatic (Inferior) Surface

The inferior, slightly concave surface of the heart that rests upon the central tendon of the diaphragm, formed mainly by the left ventricle and partly by the right ventricle.

Base (Posterior Surface) of the Heart

The posterior aspect of the heart directed toward the vertebral bodies, formed primarily by the left atrium with a smaller contribution from the right atrium.

Crista terminalis

A smooth vertical muscular ridge along the internal posterolateral wall of the right atrium that separates the smooth-walled sinus venarum from the anterior pectinate-muscled region.

Musculi pectinati (Pectinate muscles)

Prominent, comb-like muscular ridges lining the anterior internal wall of the right atrium and extending into the right and left auricles.

Fossa ovalis

An oval depression situated on the right atrial side of the interatrial septum, representing the remnant of the fetal foramen ovale and bordered by the limbus of fossa ovalis.

Trabeculae carneae

Muscular ridges and columns projecting into the lumen from the internal muscular walls of both the right and left ventricles.

Septomarginal trabecula (Moderator band)

A curved muscular band crossing the right ventricular cavity from the interventricular septum to the base of the anterior papillary muscle, carrying a component of the cardiac conduction system (right bundle branch).

Chordae tendineae

Tough, fibrous cord-like structures extending from ventricular papillary muscles to the free borders of atrioventricular valve cusps, preventing valve eversion and prolapse into the atria during ventricular systole.

Mitral valve (Bicuspid valve)

The left atrioventricular valve consisting of two cusps (anterior and posterior) that prevents retrograde blood flow from the left ventricle into the left atrium during ventricular contraction.

Cardiac auscultation sites

Anatomical surface landmarks used to listen to valve closures: Aortic valve ($2^{\text{nd}}$ right intercostal space), Pulmonary valve ($2^{\text{nd}}$ left intercostal space), Tricuspid valve ($5^{\text{th}}$ left intercostal space at sternal border), and Mitral valve ($5^{\text{th}}$ left intercostal space at the midclavicular line / apex).

Fibrous skeleton of the heart

A dense connective tissue framework composed of four fibrous rings and two trigones (right and left) that anchors the heart valves, provides attachment for the atrial and ventricular myocardium, and functions as an electrical insulator between atria and ventricles.

Sinu-atrial (SA) node

The primary specialized pacemaker of the cardiac conduction system, located in the right atrium near the opening of the superior vena cava, which initiates the spontaneous electrical depolarization waves of the heart.

Anterior interventricular branch (LAD)

A major branch of the left coronary artery that travels down the anterior interventricular sulcus toward the apex, supplying both ventricles and the anterior two-thirds of the interventricular septum.

Coronary sinus

The wide venous channel lying in the posterior atrioventricular groove that collects deoxygenated venous blood from the great, middle, small, and posterior cardiac veins and empties directly into the right atrium.

Angina pectoris

Transient chest pain or discomfort precipitated by reversible myocardial ischemia due to narrowed coronary arteries without irreversible cell necrosis.

Myocardial infarction

Irreversible necrosis and death of cardiac muscle cells caused by complete or prolonged occlusion of a coronary artery, leading to severe lack of blood flow and oxygen.

Intercalated disc

A microscopic junctional complex between adjoining cardiac muscle fibers containing adherens junctions and desmosomes for structural mechanical adhesion, and gap junctions for low-resistance electrical communication.

Tunica media

The middle layer of a blood vessel wall composed of smooth muscle cells and elastic fibers, distinctly thicker in arteries than in veins to regulate vascular diameter and withstand systemic blood pressure.

Capillary

A microscopic blood vessel consisting entirely of a single endothelial cell layer and an underlying basal lamina, devoid of smooth muscle, optimized for exchange of nutrients, respiratory gases, and wastes between blood and tissues.