THE ORGANIZATION OF THE INDIVIDUAL 



23 



ORGANS AND SYSTEMS 



Organs and systems represent successively higher stages in body 

 organization. An organ, as the term is used here, is typically composed 

 of a number of diverse kinds of tissues, brought together to perform some 

 definite and limited function that requires the cooperation of several or 

 many kinds of cells. A skeletal muscle, for example, is an organ whose 



Fig. 2.4. Types of glands. A, glandular cells in epithelium. B, simple tubular gland. C, sim- 

 ple alveolar gland. D, compound tubular gland. E, compound alveolar gland. F, simple 

 coiled tubular (sweat) gland. 



