DIRECTIONS FOB LABORATORY WORK 781 



section of a medullated nerve, a tendon or compact white fibrous tissue 

 and smooth muscle? 



(b) Non-Medullated Axon (R&mak's fibers; Unmyelinated fibers). 

 (1) Search for sympathetic (autonomic) nerves, both transversely and 

 longitudinally cut, in a stained section of some portion of the alimentary 

 tract, in the connective tissue between the two muscle layers. Note also 

 an occasional sympathetic ganglion cell. Sketch: (a) a bundle of fibers 

 cross cut (122) ; (b) longitudinally cut (123) ; and (c) several ganglion 

 cells (124). Study also a cross-section of the trunk of the vagus nerve; 

 here non-medullated fibers are mixed with medullated fibers of all sizes. 

 Sketch (125). Tease a fragment of the vagus nerve in Ringer's solu- 

 tion. Add a drop of stain. Differentiate between the myelinated and 

 unmyelinated fibers and sketch (126) a few of the latter. 



(C) GANGLIA. 



(a) Spinal (Dorsal, Sensory). (1) Study a stained section of a 

 spinal ganglion. Sketch (127) several cells. Note nucleated capsule. 

 How is this capsule related to the dendrons and to the neurolemma of 

 the axon ? Compare these cells with those of the sympathetic ganglia. 



(2) Sketch (128) the several types of atypical cells in a spinal or 

 cerebral ganglion (e.g., Gasserian) in a specially prepared section (Ran- 

 son-Cajal's pyridin-silver method). Note: (a) 'fenestrated' cells; (b) 

 multipolar cells; (c) cells with collaterals ending in 'end bulbs'; and 

 (d) the usual unipolar type. Explain the origin of the unipolar type. 

 Which of the two divisions of its single process corresponds to a den- 

 dron? 



(b) Sympathetic (Autonomic). (1) Sketch (129) small area of a 

 sympathetic ganglion (e.g., ciliary; otic; ganglia of myenteric plexus). 

 Are the cells of the sympathetic ganglia enveloped by a nucleated cap- 

 sule? 



(D) NEUROGLIA. 



Study a section of the cerebral cortex or spinal cord treated accord- 

 ing to the Golgi technic for neuroglia. Sketch: (a) a larger long-rayed 

 astrocyte (130) ; (b) a smaller short-rayed astrocyte or mossy cell 

 (131). Study a second section treated according to the Benda or Wei- 

 gert neuroglia technic. Sketch (132) a few cells and fibers. What 

 structure in ganglia is the homologue of the neuroglia of the brain and 

 spinal cord? What is the analogue? 



