112 Genekal Biology 



planes. It is areolar which forms the fascia for each muscle, and is 

 modified into a tendon at the end. 



The looser tissue of the lymphatic glands is called adenoid 

 ( ) and is composed of an irregular network of 



sheets and strands which forms a fine meshwork of supporting cells. 



The various ligaments uniting the bones are formed of a dense and 

 non-elastic variety of white fibrous tissue. White fibrous tissue is also 

 found in the cutis of the skin, the submucosa of the alimentary canal, 

 in the walls of the blood vessels, in the substance of glands, and in the 

 capsules covering various organs. 



Adipose tissue is regarded as a form of connective tissue in which 

 the cells have enlarged by being gorged with fat. The nucleus here lies 

 toward one side of the cell, while the cell-wall and a thin pellicle of pro- 

 toplasm surround the fat globule. 



Cartilage is a dense and massive variety of connective tissue. The 

 predominant type in the frog is known as hyaline ( ), 



the matrix of which appears transparent and homogeneous 

 ( ), although it really consists of numerous fibers of 



different types which can only be observed after chemical treatment. 

 The cells in this type of tissue are contained in little rounded spaces, 

 or lacunae, scattered quite irregularly through the matrix. There may 

 be two or more cells in one lacuna, which leads to the belief that the 

 cells may have been formed quite recently by a division of the parent 

 cell. An intercellular substance is deposited around each cell, there 

 being a sort of partition grown between each of the cells which gradually 

 increases in thickness and presses them farther and farther apart. The 

 outer surface of the cartilage is covered by a thin layer called the 

 perichondrium ( ). 



Hyaline cartilage is found at the ends of the bones of the limbs, 

 between the spinal vertebrae and the ends of their transverse processes, 

 at the tip of urostyle, in the pubis of the pelvic girdle, in the hyoid, and 

 the cartilage of the larynx and of both ends of the sternum. It also 

 forms the basis of the cranium and the central axis of the lower jaw. 



Calcified cartilage is that which contains a deposit of lime salts in 

 the matrix. It is found in the pelvis of old frogs, in the suprascapula, 

 and at the ends of the larger bones in the limbs such as the head of the 

 humerus and femur. 



Bone structure is quite similar to that of cartilage and also contains 

 cells embedded in a solid matrix. In bone, however, the matrix is made 

 more firm by a deposit of carbonate and sulphate of lime. If the bone 

 is immersed in acid so as to remove the lime solids, the histological 

 structure of bone is quite like that of cartilage. It does not follow from 

 this, however, that bone is merely calcified cartilage, for bone and 

 cartilage differ from each other both histologically and chemically. 

 Cartilage often is followed by bone, but when it is, the cartilage has 

 been broken down and the bony tissue has taken its place. We speak 



