Heart

The right border of the heart is formed by the

1.- Right atrium and extends to the right of the sternum Note: this border is slightly convex and nearly in line with the superior and inferior vena cava 2.-Right ventricle and a small part of the left ventricle form the inferior border of the heart

structure and function of the endocardium

1.- lies with the myocardium 2.- is the innermost layer of the heart 3.- It is a thin, smooth membrane composed of a layer of the endothelial cells

the total weight of the heart is approximately

250-350 grams, depending on age and gender Note: the weigh and size increases through life, into advanced age. the increase size is more pronounced in men than women.

the size of the human heart

In normal adults, the heart is aprox. *12 cm in length *8-9 cm in width * 6 cm thick

the right ventricle occupies most of the

anterior surface of the heart and narrows superiorly to the level of the third intercostal space

the left ventricle lies

behind the right ventricle and forms the left border of the heart, sloping to the superior margin at the third intercostal space

the left atrium receives oxygen- carrying blood from the lungs via

four (4) pulmonary veins: 1.- Right inferior 2.- right superior 3.- Left inferior 4.- left superior

the inferior margin of the heart lies just above

the diaphragm and slopes slightly to form the apex that sitsat the fifth intercostal space at the midclavicular line