156 PRACTICAL HISTOLOGY. [X. 



LESSON X. 

 CONNECTIVE TISSUE. 



THE group of Connective Tissues includes cartilage, ordinary 

 connective tissue (with adipose tissue), adenoid or retiform tissue, 

 mucous tissue, bone and dentine, (i) These all subserve more or 

 less mechanical functions in the organism; (2) they all have much 

 in common in structure, i.e., they are composed of cells, and an 

 intercellular matrix, but usually the development of the matrix 

 exceeds that of the cells ; and (3) they are all developed from the 

 mesoblast of the embryo. 



ORDINARY CONNECTIVE TISSUE. 



It consists of the following structural elements : 



A. Structural Elements. 



-r,.-, ( White or gelatinous. 

 Fibres. | Ye]lQw or & elastic> 



f fl. Flattened or lamellar cells, called also fixed oon- 



j j nective-tissue corpuscles. 



5 j Fixed . . { 2. Granular cells (eosinopliilous cells ?). 

 1,1 j 3. Vacuolated or plasma cells of Waldeyer. 



^o I I .Clasmatocytes of Ranvier (?). 



I Migratory. Wandering cells or leucocytes. 



B. Arrangement qf these Elements. 



(a.) Areolar, e.g. , subcutaneous and submucous tissues. 



(6.) Bundles in parallel groups, e.g. , tendon (with parallel fibres) and 



fasciae (fibres crossing at right angles), 

 (o.) Fenestrated fibrous membranes, e.g., omentum. 

 (d.) Compact bundles crossing in all directions, e.g., skin. 



The lamellar cells are flattened or winged plates which lie on 

 the bundles of fibrils. They have a large oval nucleus lying in a 

 clear plate. 



The granular cells, or " Mastzellen " of Ehrlich, are often found 

 near blood-vessels, and in the -fat present in areolar tissue, in 

 the submucous tissue of the intestine, and in Glisson's capsule. 

 The cells are often spherical, and the granules are numerous and 

 proteid in nature, and stain with aniline dyes, e.g., cosin, hence 

 the term sometimes applied to them "eosinopliilous cells." 



The plasma cells were formerly confused with the foregoing, 



