CHAPTER 



FOURTH. 



THE CIRCULATING SYSTEM. — ANGIOLOGY, OR HISTORY OF 

 THE ORGANS OF BLOOD CIRCULATION. 



DEFINITIONS AND DESCRIPTIONS. 



365. The Circulatory Org 

 this system are the Heart, 

 Arteries, Veins, and Capil- 

 laries, and are mainly tubes 

 of various diameters and a 

 hollow organ, with the double 

 office of receiving and propel- 

 ling the blood. 



366. The Heart. — The 

 Heart, or central engine of 

 circulation, is located in the 

 thorax or chest, resting by its 

 lower surface on the dia- 

 phragm, and somewhat to the 

 left of the middle line of the 

 body. It is of a conical form, 

 made of animal muscular fiber, 

 the fibers crossing themselves 

 in at least three directions; 

 and it is a singular fact that 



ans, — The organs composing 

 Fig. 202. 



An Anterior view of the Heart in a Ver- 

 tical Position, with its Vessels injected. 1, 

 Eight Auricle. 2, Left Auricle. 3, Right 

 Ventricle. 4, Left Ventricle. 5, Descend- 

 ing Vena Cava. 6, Aorta. 7, Left Pulmo- 

 nary Artery. 8, The Arteria lnnominata. 

 9, Left Primitive Carotid. 10, Left Sub- 

 clavian Artery. 11, Anterior Cardiac Ves- 

 sels in the Vertical Fissure. 12, Posterior 

 Vessels from the Transverse Fissure. 13, 

 Main Trunk of the Pulmonary Artery. 



365. What are the organs used for the circulation of the blood ? 366. Give the location 

 of the Heart. 



