688 



ANGIOLOGY 



Lympn Glands (lymphoglandulce] . The lymph glands are small oval or bean- 

 shaped bodies, situated in the course of lymphatic and lacteal vessels so that the 

 lymph and chyle pass through them on their way to the blood. Each generally 

 presents on one side a slight depression thehilus through which the bloodvessels 

 enter and leave the interior. The efferent lymphatic vessel also emerges from the 

 gland at this spot, while the afferent vessels enter the organ at different parts of 

 the periphery. On section (Fig. 597) a lymph gland displays two different struc- 

 tures: an external, of lighter color the cortical; and an internal, darker the 

 medullary. The cortical structure does not form a complete investment, but is 

 deficient at the hilus, where the medullary portion reaches the surface of the 

 gland; so that the efferent vessel is derived directly from the medullary structures, 

 while the afferent vessels empty themselves into the cortical substance. 



Lymphoid 



tissue in 



cortex 



Svbcapsular 

 lymph-path 





Lymph-path 

 in medulla 



FIG. 597. Section of small lymph gland of rabbit. X 100. 



Structure of Lymph Glands. A lymph gland consists of (1) a fibrous envelope, or capsule, 

 from which a frame-work of processes (trabeculce) proceeds inward, imperfectly dividing the 

 gland into open spaces freely communicating with each other; (2) a quantity of lymphoid tissue 

 occupying these spaces without completely filling them; (3) a free supply of bloodvessels, which 

 are supported in the trabeculae; and (4) the afferent and efferent vessels communicating through 

 the lymph paths in the substance of the gland. The nerves passing into the hilus are few in 

 number and are chiefly distributed to the bloodvessels supplying the gland. 



The capsule is composed of connective tissue with some plain muscle fibers, and from its internal 

 surface are given off a number of membranous processes or trabeculse, consisting, in man, of 

 connective tissue, with a small admixture of plain muscle fibers; but in many of the lower animals 

 composed almost entirely of involuntary muscle. They pass inward, radiating toward the center 

 of the gland, for a certain distance that is to say, for about one-third or one-fourth of the space 

 between the circumference and the center of the gland. In some animals they are sufficiently 

 well-marked to divide the peripheral or cortical portion of the gland into a number of compart- 

 ments (so-called follicles), but in man this arrangement is not obvious. The larger trabeculae 

 springing from the capsule break up into finer bands, and these interlace to form a mesh-work 

 in the central or medullary portion of the gland. In these spaces formed by the interlacing 

 trabeculae is contained the proper gland substance or lymphoid tissue. The gland pulp does 

 not, however, completely fill the spaces, but leaves, between its outer margin and the enclosing 

 trabeculae, a channel or space of uniform width throughout. This is termed the lymph path 



