CONNECTIVE TISSUE. 



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connective tissue. It has been called cellular, areolar or fibrous, but most 

 of these names were given to it without a clear idea of its structure. Its prin- 

 cipal anatomical element is a fibre of excessive tenuity, wavy and with a sin- 

 gle contour. These fibres are collected into bundles of variable size and 

 are held together by an adhesive amorphous substance. The wavy lines that 

 mark the bundles of fibres give them a very characteristic appearance. 



The direction and arrangement of the fibres in the various tissues present 

 marked differences. In the loose areolar tissue beneath the skin and between 

 the muscles., and in the loose structure surrounding some of the glands and 

 connecting the sheaths of blood-vessels and nerves to the adjacent parts, the 

 bundles of fibres form a large net-work and are very wavy in their course. 

 In the strong, dense membranes, as the aponeuroses, the proper coats of many 

 glands, the periosteum and perichondrium and the serous membranes, the 

 waves of the fibres are shorter, and the fibres themselves interlace much more 

 closely. In the ligaments and tendons, the fibres are more nearly straight 

 and are arranged longitudinally. 



On the addition of acetic acid the bundles of inelastic fibres swell up, 

 become semi-transparent, and the nuclei and elastic fibres are brought into 



FIG. 153. Loose net-work of connective tissue from the human subject, showing the fibres and cells 



(Rollett). 

 a, a, a capillary blood-vessel. 



view. The proportion of elastic fibres differs very much in different situa- 

 tions, but they are all of the smallest variety, and they present a striking 

 contrast to the inelastic fibres in their form and size. Although they are 

 very small, they always present a double contour. 



Certain cellular and nuclear elements are always found in the connective 

 tissue. The cells are known as connective-tissue cells. They are very irregu- 

 lar in size and form, some of them being spindle-shaped or caudate, and 



