KPITIIKLU'M. -M) 



so great that a net-like structure results. This is known as a 

 net-like or reticular tubular gland (liver). Most of the glands 

 of the body are tubular. We distinguish the following : 



(a) Simple unbranched tubular glands: fund us glands, 

 glands of Lieberkiihn, and the coil glands. 



(b) Simple branched tubular glands : pyloric glands, Brun- 

 ner's glands, small serous and mucous glands of the oral cavity, 

 uterine glands. 



(<} Compound tubular glands: salivary glands, lachrymal 

 glands, kidneys, testes, liver, Cowper's and Bartholini's glands, 

 and the prostate body. 



Similarly we distinguish between simple and compound 

 alveolar glands. The simple ones may be branched or 

 unbranched. Branched glands consist of many alveoli, com- 

 bined to form an alveolar system, and opening into a duct. If 

 many of such systems join to form a gland, we have to do with 

 a compound alveolar gland. Here, as in compound tubular 

 glands, many ducts open into a main duct. These may be put 

 down as follows : 



(a) Unbranched simple alveolar glands : small sebaceous 



glands. 



(b) Branched alveolar glands : large sebaceous glands, and 

 the Meibomian glands. 



(c) Compound alveolar glands : lungs, and mammary glands. 

 Some authors speak of a transition form, the so-called 



tubulo-alveolar glands. They claim that such glands as the 

 salivary glands have alveolar dilatations at the end of the 

 tubuli. 



Some glands possess no duct, as this has in the course of 

 development been closed. Such glands get rid of their secre- 

 tion in two ways. ' In the ovary, for example, the egg cell 

 bursts out from the Grraafian follicle and comes to the outside 1 

 world. This is a so-called dehiscent gland. Other glands 

 without a duct, such as the thyroid, adrenal, hypophysis, pass 

 their secretion into the blood which flows through them. This 

 is what is known as internal secretion. Certain glands have 

 both an external and an internal secretion, the functions of the 



