204 



HITCHCOCK'S ANATOMY 



Fig. 206. point where the arteries are given off 



from each ventricle are found (in each) 

 three crescent-shaped folds of semi- 

 cartilaginous tissue called Semi-lunar 

 Valves, to allow the motion of blood in 

 an outward direction, but to prevent 

 the return, which is called regurgita- 

 tion. 



369. Pericardium, — In addition to 

 the fasciae and fatty matter which im- 

 mediately invest the heart, this organ is enclosed in another mem- 

 brane in the form of a shut sac, a fibro -serous membrane called 



Semi-lunar Valves of the 

 Heart closed. 



Fig. 207. 



Semi-lnnar Valves of the Aorta laid open, rr, Corpus Arantii on the Free Border. &, 

 Attached Border, c, Orifices of Coronary Arteries. 



the Pericardium (meaning about the heart). This contains a 

 small quantity of a fluid like water, so that the heart actually 

 floats in a liquid, and does not rest firmly upon any hard sur- 

 face. The pericardium not only exists as a loose sac about 

 the heart, but it is reflected upon it where the vessels are 

 given off ; covering it in the same manner as the fasciae cover 

 and protect the muscles. 



370. Arteries — Their Coats .—The Arteries are tough and 

 cylindrical tubes which convey the blood from the heart to the 

 different parts of the body. They are made up of three mem- 



Describe the Semi-lunar Valves and their location. 369. What is the sac called that 

 surrounds the heart ? What fluid does it contain? How much of it is there? Is the 

 pericardium attached at all to the heart? 370. Of how many coats are the arteries com- 

 posed ? 



