20 ELEMENTS OF MAMMALIAN ANATOMY 



sarcolcmma, the nucleus is central, and the shape is spindle-like 

 or the cells may be joined together to form a syncytium (Fig. 8). 

 The cardiac muscle is composed of broad branching fibers of 

 cells united into a syncytium. The nucleus is central and the 

 fibrils striated. A sarcolemma has been described surrounding 

 the cardiac libers (Fig. 9). 



Nucleus. Sarcoplasm. Fibrils. Lateral branch. 



X. Conn, tissue. Capillaries. 



Fig. 9. — Longitudinal Section of a Papillary Muscle from the Human 



Heart. X 240. {Lewis and Stohr.) 

 The transverse lines (x) are partly light (where the fiber has broken) and partly 



dark (intercalated discs). 



Nervous tissues are made up of two kinds of elements: 

 nerve cells and nerve fibers. Nerve cells vary much in size and 

 shape, but typically comprise cell body, a fiber-process or axone, 

 and a series of branching processes, the dendrites. The nerve 

 cell with all its processes is known as a neurone (Fig. 112). The 

 nerve fiber has as its axis or core the axone, which in most cases 



