112 VASCULAR SYSTEM. 



tected, is this protection the only benefit derived by^ the 

 arteries? 



<ft. It is not; for the motions of the parts in which 

 the yood-vessels are imbedded facilitates the passage of 

 blood, and the arterial pulsation itself favours the func- 

 tional operations and vital activity of the surrounding 

 organs. 



Q. What are the advantages of the tortuous arterial 

 courses? 



#. It serves to protect the arteries themselves from in- 

 jury, in the action of some parts; and again, it in other 

 parts tends to the safety of the organs. 



Q. What is the use of arterial anastomosis? 



A. It facilitates the passage of blood into the capillaries, 

 whose vitality being so often deranged are liable to con- 

 gestion. You are well aware of the value of anastomosis, 

 after taking up principal arterial trunks. 



Q. Is the sum of the diameter of the branches equal to 

 the calibre of the trunk? 



/#. It exceeds it. 



Q. Why is aneurism more frequent in the aorta than in 

 remoter parts of the arterial system ? 



ft. Because in proportion to the calibre of the artery, 

 the parietes are thinner than in the other arteries. 



Q. Where do the arteries terminate? 



<ft. In the capillaries. 



On the Organization of the Vascular System with Red 

 Blood. 



Q. In what arteries is their peculiar coat thickest? 

 #. In the large arteries, and it becomes thinner in the 



