Question

peripheral nervous system
the peripheral nervous system (pns) consists of nerves and scattered ganglia (groups of neuronal cell bodies found outside the cns). we have already considered one type of ganglion—the dorsal root (1. ) of the spinal cord. we will cover others in the discussion of the autonomic nervous system. here, we will concern ourselves only with nerves.
structure of a nerve
as noted earlier in this chapter, a nerve is a bundle of neuron fibers found outside the cns. within a nerve, neuron fibers, or processes, are wrapped in protective connective tissue coverings. each fiber is surrounded by a delicate (2. ) tissue sheath, an endoneurium (endo - nure - um). groups of fibers are bound by a coarser connective tissue wrapping, the perineurium (pert - nure - um), to form fiber bundles, or fascicles. finally, all the fascicles are bound together by a tough fibrous sheath, the (3. ), to form the cordlike nerve (figure 7.22, p. 257).
conceptlink
the terms for the connective tissue coverings of a nerve should seem familiar. we discussed similar structures in the muscle chapter (figure 6.1, p. 183). names of muscle structures include the root word mys, whereas the root word neuro tells you that the structure relates to a nerve. for example, the endomysium covers one individual (4. ) fiber, whereas the endoneurium covers one individual neuron fiber.
like neurons, nerves are classified according to the direction in which they transmit impulses. nerves that carry impulses only toward the cns are called sensory (afferent) nerves, whereas those that carry only motor fibers are motor (efferent) nerves. nerves carrying both sensory and motor fibers are called mixed nerves, all (5. ) nerves are mixed nerves.

1 spinal 2 ganglion 3 connective 4 epineurium 5 muscle

1 connective 2 epineurium 3 muscle 4 spinal 5 ganglion

1 muscle 2 spinal 3 ganglion 4 connective 5 epineunum

1 epineurium 2 muscle 3 spinal 4 ganglion 5 connective

1 ganglion 2 connective 3 epineurium 4 muscle 5 spinal

Explanation:

1. The dorsal root of the spinal cord is a type of ganglion, so 1 is ganglion.
2. Each fiber in a nerve is surrounded by a delicate connective - tissue sheath, so 2 is connective.
3. All the fascicles are bound together by a tough fibrous sheath, the epineurium, so 3 is epineurium.
4. The endomysium covers one individual muscle fiber, so 4 is muscle.
5. All spinal nerves are mixed nerves, so 5 is spinal.

Answer:

1. ganglion 2. connective 3. epineurium 4. muscle 5. spinal