Concepts of Human Anatomy & Physiology   5/e   Van De Graaff/Fox
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I. Structure of the Heart

Concept: The structure of the heart enables it to serve as a transport system pump that keeps blood continuously circulating through the blood vessels of the body.

II. Cardiac Cycle, Heart Sounds, and the Electrocardiogram

Concept: The two atria fill with blood and then contract simultaneously. This is followed by the simultaneous contraction of both ventricles, which sends blood through the pulmonary and systemic circulations. The AV valves close when the ventricles contract, and the semilunar valves close when the ventricles relax, producing the heart sounds. Contraction of the myocardium results from electrical excitation, which can be recorded as an electrocardiogram.

III. Blood Vessels

Concept: The structure of arteries and veins allows them to transport blood from the heart to the capillaries and from the capillaries back to the heart. The structure of capillaries permits the exchange of blood plasma and dissolved molecules between the blood and surrounding tissues.

IV. Principal Arteries of the Body

Concept: The aorta ascends from the left ventricle to a position just above the heart, where it arches to the left and then descends through the thorax and abdomen. Branches of the aorta carry oxygenated blood to all of the cells of the body.

V. Principal Veins of the Body

Concept: After systemic blood has passed through the tissues, this oxygen-depleted blood is returned through veins of progressively larger diameters to the right atrium of the heart.

VI. Fetal Circulation

Concept: All of the respiratory, excretory, and nutritional needs of the fetus are provided for by diffusion across the placenta instead of by the fetal lungs, kidneys, and gastrointestinal tract. Fetal circulation is adaptive to these conditions.

VII. Development of the Heart

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