BODY TISSUES 



307 



FIGURE 13-3. Motor neuron sliowing the nerve cell with dendrites (D) which pick 

 up the impulse for transmission through the axon (A) and terminal arborizations 

 (T) to the site of action. Such cells transmit impulses only in the direction of the 



terminal arborizations. 



/ 



o 



CHs 



CH3C— O— CH2CH2— N+— CH3 



CH3 



acetylcholine 



decreases sharply on transmission of an impulse (Figme 13-4). Young 

 rats contain 7 to 12 m/j. moles of acetylcholine per g. of brain tissue. 

 With the application of current across inserted electrodes, this level 



