Cardiovascular System

Middle Mediastinum

Contains the heart, pericardium, and roots of the great vessels.

Pericardium

Fibroserous sac enclosing the heart and roots of the great vessels.

Fibrous Pericardium

Tough, inelastic outer layer anchoring the heart to the diaphragm and great vessels.

Serous Pericardium

Inner layer with parietal and visceral (epicardium) parts.

Parietal Layer

Lines the fibrous pericardium.

Visceral Layer (Epicardium)

Covers the surface of the heart.

Pericardial Cavity

Space between pericardial layers containing serous fluid.

Apex of Heart

Points downward, forward, and to the left.

Base of Heart

Posterior surface directed backward and to the right.

Anterior Surface

Sternocostal surface against sternum and ribs.

Inferior Surface

Diaphragmatic surface resting on the diaphragm.

Right Pulmonary Surface

Surface contacting the right lung.

Left Pulmonary Surface

Surface contacting the left lung.

Right Atrium

Receives deoxygenated blood from SVC, IVC, and coronary sinus.

Left Atrium

Receives oxygenated blood from four pulmonary veins.

Right Ventricle

Pumps blood into pulmonary trunk through pulmonary valve.

Left Ventricle

Pumps blood into aorta through aortic valve.

Endocardium

Inner smooth lining of the heart.

Myocardium

Muscular layer responsible for contraction.

Epicardium

Outer covering of the heart (visceral pericardium).

Atrioventricular Sulcus

Groove separating atria from ventricles.

Interventricular Sulcus

Groove dividing right and left ventricles.

Auricle

Muscular pouch of each atrium.

Crista Terminalis

Ridge separating smooth and rough parts of right atrium.

Pectinate Muscles

Muscles in atria that aid in expansion.

Sinus Venarum

Smooth posterior wall of right atrium receiving venous openings.

Fossa Ovalis

Remnant of fetal foramen ovale.

Chordae Tendineae

Fibrous cords connecting valve cusps to papillary muscles.

Papillary Muscles

Muscles that prevent AV valve prolapse during contraction.

Trabeculae Carneae

Irregular muscular ridges in ventricles.

Supraventricular Crest

Muscular ridge dividing inflow and outflow tracts of right ventricle.

Moderator Band

Conduction pathway in right ventricle connecting septum to papillary muscle.

Tricuspid Valve

Right atrioventricular valve with three cusps.

Bicuspid (Mitral) Valve

Left atrioventricular valve with two cusps.

Pulmonary Valve

Semilunar valve between right ventricle and pulmonary trunk.

Aortic Valve

Semilunar valve between left ventricle and aorta.

Cardiac Cycle

Sequence of contraction and relaxation of heart chambers during one heartbeat.

Atrial Systole

Atria contract to push blood into ventricles.

Ventricular Systole

Ventricles contract, ejecting blood into arteries.

Ventricular Diastole

Ventricles relax and refill with blood.

Heart Sound S1 (Lub)

Closure of AV valves at the start of ventricular systole.

Heart Sound S2 (Dub)

Closure of semilunar valves at the start of ventricular diastole.

Sinoatrial (SA) Node

Pacemaker of the heart initiating impulses.

Atrioventricular (AV) Node

Delays impulse before ventricular contraction.

Bundle of His

Conducts impulses from AV node to ventricles.

Right Bundle Branch

Conduction pathway along right side of septum.

Left Bundle Branch

Conduction pathway along left side of septum.

Purkinje Fibers

Distribute impulse through ventricular myocardium.

Sympathetic Stimulation

Increases heart rate and contractility.

Parasympathetic Stimulation

Decreases heart rate.

Blood Vessels

Tubes that carry blood throughout the body.

Pulmonary Vessels

Carry blood between the heart and lungs.

Systemic Vessels

Carry blood between the heart and the rest of the body.

Tunica Intima

Inner smooth lining minimizing friction.

Tunica Media

Middle muscular layer controlling vessel diameter.

Tunica Externa

Outer connective tissue layer anchoring vessels.

Arteries

Thick-walled vessels carrying blood away from the heart.

Veins

Vessels carrying blood toward the heart; contain valves.

Capillaries

Smallest blood vessels for exchange of materials.

Continuous Capillaries

Capillaries with uninterrupted endothelium.

Fenestrated Capillaries

Capillaries with pores for rapid exchange.

Sinusoidal Capillaries

Capillaries with wide gaps for large exchange.

Systemic Circulation

Left ventricle → body → right atrium.

Pulmonary Circulation

Right ventricle → lungs → left atrium.

Coronary Circulation

Circulation supplying the heart muscle itself.

Hepatic Portal Circulation

Blood from GI organs to liver for processing.

Renal Circulation

Blood flow through kidneys for filtration and regulation.

Circle of Willis

Arterial ring at brain base ensuring constant cerebral blood flow.

Right Coronary Artery

Supplies right atrium, ventricle, and part of septum.

Left Coronary Artery

Divides into anterior interventricular and circumflex arteries.

Coronary Sinus

Venous channel returning blood from myocardium to right atrium.

Superior Vena Cava

Returns blood from upper body to right atrium.

Inferior Vena Cava

Returns blood from lower body to right atrium.

Aorta

Main systemic artery carrying blood from left ventricle to body.

Pulmonary Trunk

Artery carrying deoxygenated blood from right ventricle to lungs.

Right Pulmonary Artery

Carries blood to right lung.

Left Pulmonary Artery

Carries blood to left lung.

Right Pulmonary Veins

Carry oxygenated blood from right lung to left atrium.

Left Pulmonary Veins

Carry oxygenated blood from left lung to left atrium.