SOLUTIONS TO EXERCISES, LESSON 11
Two types of nervous tissues are neurons (nerve cells) and glia (neuroglia). The
neuron is the basic structural unit of the nervous system. The glia are cells of
Nervous tissues are specialized to:
A neuron is a nerve cell body and all of its processes. (para 11-3)
A dendrite carries impulses toward the cell body. (para 11-5a)
An axon is a neuron process which transmits information from the cell body to the
More than two poles: multipolar neuron.
Two poles: bipolar neuron.
One pole: unipolar neuron.
From receptor organs to the CNS: sensory neurons.
From the CNS to muscles and glands: motor neurons.
The term "continuity without contact" refers to the fact that neurons do not actually
touch. Thus, there is no electrical transmission of impulses from one neuron to the
next. In fact, information is transferred across the synaptic cleft by chemicals
A synapse is a "connection" between two neurons. An axon terminates in tiny
branches. At the end of each branch is a terminal bulb. Neurotransmitters are
stored in bundles called synaptic vesicles located within each terminal bulb. The
presynaptic membrane is the thickened layer of the terminal bulb which faces the
synaptic cleft and through which pass the neurotransmitters before entering the
synaptic cleft. The synaptic cleft is the space between the terminal bulb of the first
neuron and the dendrite or cell body of the second neuron. The postsynaptic
membrane is that portion of the membrane of the second neuron which lies near