40 



ANATOMY FOR NURSES 



[Chap. IV 



plates wrapped around them. It forms a fine framework in many 

 organs. 



Lymphoid or adenoid ' tissue. — This is reticular tissue in which 

 the meshes of the network are occupied by lymph corpuscles. 

 This is the most common condition of retiform tissue. 



Function. — Lymphoid tissue forms the principal part of the 

 substance of the spleen and lymph nodes. It also enters into the 

 composition of the tonsils and some of the intestinal glands. 



Cartilage. — This is the well-known substance called " gristle." 

 Although cartilage can be readily cut with a sharp knife, it is never- 

 theless of very firm consistence, but at the same time highly elastic, 



so that it readily yields to exten- 

 sion or pressure, and immediately 

 recovers its original shape when 

 the constraining force is with- 

 drawn. When a very thin section 

 is examined with a microscope, it 

 is seen to consist of nucleated cells 

 disposed in small groups in a mass 

 of intercellular substance. This 

 intercellular substance is some- 

 times transparent, and to all ap- 

 pearances structureless ; some- 

 times it is pervaded with white 

 fibres and sometimes with yellow 

 fibres. According to the amount 

 and texture of the intercellular 

 substance, we distinguish three 

 principal varieties : — 



(1) Hyaline or true cartilage. 



(2) White fibro-cartiloge. 



(3) Yellow or elastic fihro-cartilage. 

 Hyaline cartilage. — This variety is named from the Greek 



word for glass. A comparatively small number of cells are em- 

 bedded in an abundant quantity of intercellular substance which 

 has the appearance of ground glass. 



White fibro-cartilage. — The intercellular substance is pervaded 



Z. SAILS 



Fio. 18. — Articular Hyaline 

 Cartilage from the Femur of an 

 Ox. s, intercellular substance; p, pro- 

 toplasmic cell ; n, nucleus. (Ranvier.) 



1 Adenoid (from the Greek aden, "a gland," and eiodos, " form" or "resemblance." 

 Pertaining to or resembling a gland. 



