Heart Anatomy

§Approximately the size of  fist

§Location

§Superior surface of diaphragm

§Left of the midline

§Anterior to the vertebral column, posterior to the sternum

Coverings of the Heart: Anatomy

§Pericardium – a double-walled sac around the heart composed of:

        A superficial fibrous pericardium

        A deep two-layer serous pericardium

        The parietal layer lines the internal surface of the fibrous pericardium

        The visceral layer or epicardium lines the surface of the heart

       They are separated by the fluid-filled pericardial cavity

§Epicardium – visceral layer of the serous pericardium

§Myocardium – cardiac muscle layer forming the bulk of the heart

§Endocardium – endothelial layer of the inner myocardial surface

External Heart: Major Vessels of the Heart (Anterior View)

  §Vessels returning blood to the heart include:

        Superior and inferior venae cavae

        Right and left pulmonary veins

  §Vessels conveying blood away from the heart include:

        Pulmonary trunk,     which splits into right and left pulmonary arteries

        Ascending aorta (three branches) –

        Brachiocephalic

        Left common carotid

        Subclavian arteries

External Heart: Vessels that Supply/Drain the Heart (Anterior View)

§Arteries – right and left coronary (in atrioventricular groove), marginal, circumflex, and anterior interventricular arteries

§Veins – small cardiac, anterior cardiac, and great cardiac veins

External Heart: Major Vessels of the Heart (Posterior View)

§Vessels returning blood to the heart include:

Right and left pulmonary veins

Superior and inferior venae cavae

§Vessels conveying blood away from the heart include:

Aorta

Right and left pulmonary arteries

External Heart: Vessels that Supply/Drain the Heart (Posterior View)

§Arteries – right coronary artery (in atrioventricular groove) and the posterior  interventricular artery (in interventricular groove)

§Veins – great cardiac vein, posterior vein to left ventricle, coronary sinus, and middle cardiac vein

Gross Anatomy of Heart: Frontal Section

 Atria of the Heart

§Atria are the receiving chambers of the heart

§Each atrium has a protruding auricle

§Pectinate muscles mark atrial walls

§Blood enters right atria from superior and inferior venae cavae and coronary sinus

§Blood enters left atria from pulmonary veins

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Ventricles of the Heart

§Ventricles are the discharging chambers of the heart

§Papillary muscles and trabeculae carneae muscles mark ventricular walls

§Right ventricle pumps blood into the pulmonary trunk

§Left ventricle pumps blood into the aorta

Pathway of Blood Through the Heart and Lungs

§Right atrium à tricuspid valve à right ventricle

§Right ventricle à pulmonary semilunar valve à pulmonary arteries à lungs

§Lungs à pulmonary veins à left atrium

§Left atrium à bicuspid valve à left ventricle

§Left ventricle à aortic semilunar valve à aorta

§Aorta à systemic circulation

Pathway of Blood Through the Heart and Lungs

Coronary Circulation

§Coronary circulation is the functional blood supply to the heart muscle itself

§Collateral routes ensure blood delivery to heart even if major vessels are occluded

Coronary Circulation: Arterial Supply

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Heart Valves

§Heart valves ensure unidirectional blood flow through the heart

§Atrioventricular (AV) valves lie between the atria and the ventricles

§AV valves prevent backflow into the atria when ventricles contract

§Chordae tendineae anchor AV valves to papillary muscles

Heart Valves

§Semilunar valves prevent backflow of blood into the ventricles

§Aortic semilunar valve lies between the left ventricle and the aorta

§Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk

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Note: Images are subjected for representative purposes only.