106 



ANATOMY FOR NURSES. 



[Chap. IX. 



Fig. 80. — Diagram of Heart and Peri- 

 cardium. In A, heart and pericardium lying 

 separately. In B, pericardium lying around 

 heart. 7/, heart; P, pericardium; P.O. peri- 

 cardial cavity ; P.P. parietal portion of pericar- 

 dium ; V.P. visceral portion. 



serous fluid. As their 

 opposing surfaces, owing 

 to the constant contrac- 

 tions of the heart, are 

 continually sliding one 

 upon the other, they are 

 admirably constructed to 

 protect the heart from any 

 loss of power by friction. 

 The interior of the 

 heart is lined by a deli- 

 cate, smooth membrane, 

 called the endocardium. 

 This pavement membrane lines all the cavities of the heart, 



and is continued into 

 the blood-vessels, form- 

 ing their innermost coat. 

 The cavities of the 

 heart. — The heart is 

 divided from the base 

 to the apex, by a fixed 

 partition, into a right 

 and left half. The two 

 sides of the heart have 

 no communication with 

 ch other: the right 

 side always contains 

 venous, and the left 

 ide arterial, blood. 

 Each half is sub- 

 divided into two 

 cavities, the up- 

 per, called auri- 

 cle ; the lower, 

 ventricle. These 

 cavities com- 

 municate with 

 Fig. 81. — Right Side of Heart. A, cavity of right ven- .-, i 



tricle ; 5, sup. vena cava; C, inf. vena cava; «, wall of right ^^^® anotner Dy 

 ventricle; 6, c, columnie carneae ; r/, pulmonary vein ; e,/, tri- means of COn- 

 cuspid valve; m, semilunar valve; o, wall of left ventricle ; . • - i 

 p, q, V, ascending aorta, arch and descending aorta. StriCtecl Open- 



