Biology Questions and Answers
(impulses that command some body
action).
- What are nerves?
Axons extend throughout the inside nerves. Nerves are axon-body
containing structuraxons and covered by connective tissue.es presenting many (^)
The nerves connect neural nuclei and
ganglia with the tissues.
Nerves may contain only sensory axons
(sensory n(motor neurons) or erves), only mboth types ootor axonsf axons (^)
(mixed nerves).
- What are ganglia?
Ganglia (singular ganglion), ganglia, are structures located oor neuralutside (^)
the central nervous system (for
example, near viscera) mabeside the spinal columde of concentrationn or of (^)
neuron bodies.
Examples oganglia that concentrate f neural ganglia are cell bodies ofthe (^)
sensory nthe spinal cord and the ganglia of theeurons in the dorsal roots of
myenteric plexus responsible for the
peristaltictube. movements of the digestive
In the central neconcentrations ofrvous system neuron bodies are (CNS) the
called nuclei and not ganglia.
- What is meant by the
peripheral nervous system
(PNS)?
The peripheral ncomprehends the nerves and ganglia ofervous system (^)
the body.
- What is the function of the
myelin sheath? Do all axons
present a myelin sheath?
The function oimprove the safety anf the myelin d speed of thesheath is to
neural impulse transmission along the
axon. The myelin shelectrical insulator peath sereventing therves as an
dispersion of the impulse to other
adjacent structures. Sisheath has gaps called Ranviers’ nce the myelinnodes (^)
in its length, the neural impulse “jumps”
from one node to another thusincreasing the speed of the neural (^)
transmission.
Not all nThere are myelinated eurons have a myelin shaxonal fibers andeath. (^)
unmyelinated ones.
- What are the cells that
produce the myelin sheath? Of
which substance is the myelin
sheath formed?
In the central nervous system (CNS) the
myelin sholigodendrocyte meath is made by apposition ofembranes. Each
oligodendrocyte can cover portions of
axons of several dthe peripheral nervous system (PNS)ifferent neurons. In
the myelin sheath is made by
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