Question

Distinguish between:

1. afferent neurons and efferent neurons
2. impulse conduction in a myelinated nerve fiber and unmyelinated nerve fiber
3. cranial nerves and spinal nerves.

Answer 1

a. afferent neurons and efferent neurons

Afferent Neurons	Efferent Neurons
They transport sensory signals to the central nervous system from receptors.	They transport motor impulses from the brain to the muscles and other effector organs.
They can be found in the sense organs.	The spinal cord and the brain both contain them.
These neurons are sensory ones.	These are motor neurons.

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b. impulse conduction in a myelinated nerve fiber and unmyelinated nerve fiber

Impulse Conduction in a Myelinated Nerve Fiber	Impulse Conduction in Non-myelinated Nerve Fiber
The path of an impulse is node to node.	The impulse traverses the complete length of the nerve fiber.
Conduction speed is 50 times faster than in non-myelinated nerve fibers.	The rate of conduction is slower.
Less energy is used during impulse transmission.	More energy is used during impulse transmission.

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c. cranial nerves and spinal nerves

Cranial Nerves	Spinal Nerves
The cranial nerves come in 12 pairs.	The spine has 31 pairs of nerves.
They originate in the brain and spread to other body parts	They start in the spinal cord and spread to other bodily regions.
They could be mixed, sensory, or motor.	They have a mixture of nerves.