22 THE ELEMENTARY TISSUES 



esophagus to the anus, (2) in the capsule of the pelvis of the 

 kidney, (3) in the trachea and bronchi, (4) in the ducts of 

 glands, (5) in the gall-bladder, (6) in the vas deferens and 

 seminal vesicles of the male reproductive organs, (7) in the 

 uterus, vagina and oviducts of the female reproductive or- 

 gans, (8) in the blood-vessels and lymphatics, (9) in the 

 iris, ciliary bodies and eye-lids, and ( 10) in the hair follicles, 

 sweat glands, and skin of the scrotum and in some other 

 places throughout the body. 



The structural unit of smooth muscle is the fiber-cell 

 which is a delicate spindle with its nucleus usually situated 

 nearer one end than the other. The nuclei of the fiber-cells 

 are usually elongated and oval. These fiber-cells are held 

 together by a delicate connective-tissue network which is 

 composed of both white and elastic fibers. Smooth muscle 

 is very poorly supplied with blood-vessels in comparison to 

 striated muscle. The blood-vessels run along the connective- 

 tissue septa and small branches are distributed to the fiber- 

 cells. The lymphatics, also, follow the connective-tissue 

 septa. The nerves which supply the smooth muscle are from 

 the sympathetic system. 



The Nervous Tissues. 



These tissues will be considered under the chapter on the 

 Physiology of the Nervous System. 



