42 



THE ESSENTIALS OF HISTOLOGY 



external auditory meatus, the larynx, and the windpipe ; in these places 

 it serves to maintain the shape and patency of the orifices and tubes. 



Articular cartilage. The cells of articular cartilage are mostly 

 scattered in groups of two or four throughout the matrix (fig. 48). 

 The latter is free from fibres, except at the extreme edge of the 



FIG. 48. ARTICULAR CARTILAGE FROM HEAD OF METATARSAL BONE OF MAN 

 (OSMIC ACID PREPARATION). THE CELL-BODIES ENTIRELY FILL THE SPACES 

 IN THE MATRIX. (340 diameters.) 



a, group of two cells ; 6, group of four cells ; h, protoplasm of cell, with g, fatty granules 



n, nucleus. 



cartilage, where the connective-tissue fibres from the synovial mem- 

 brane extend into it ; and here also the cartilage-cells are often 

 branched, and offer transitions to the branched connective-tissue cor- 

 puscles of that membrane (transitional cartilage, fig. 49). By long 

 maceration, however, some observers have obtained evidence of a 

 fibrous structure even in the matrix of true hyaline cartilage. The 

 matrix immediately around the cartilage-cells is often marked off from 

 the rest by a concentric line or lines, this part being known as the 

 capsule of the cell. The cells are bluntly angular in form, the sides 

 opposite to one another in the groups being generally flattened. The 

 protoplasm is very clear, but it may contain droplets of fat ; and with 

 a high power fine interlacing filaments and granules have been 

 observed in it (fig. 50). During life the protoplasm entirely fills the 



