Mixed cranial nerves containing both motor and sensory fibers include all except which of the following?
a. oculomotor
b. facial
c. trigeminal
d. olfactory

Answer is option D.

Olfactory nerve is a sensory cranial nerve.

Explanation:

Nerves are the part of peripheral nervous system, which transmit signals from brain or spinal cord (central nervous system) to the different parts of the body and vice versa.

Based on the direction of signal transmission, they are classified into three groups;  sensory nerves (afferent nerves) pass signals from sensory receptors (pain, pressure, temperature etc) in various parts of the body to the central nervous system, motor nerves (efferent nerves) transmit signals from the central nervous system to the muscles and glands all throughout the body, mixed nerves contain both sensory and motor fibers which conduct both sensory information and muscle commands throughout the body.

Based on where they are connected to the central nervous system, they are classified into two groups; spinal nerves connected to the spinal cord and cranial nerves attached to the brain.  All the 31 spinal nerves are combined sensory and motor axons.

Of the 12 cranial nerves, three are sensory nerves, four are motor nerves and five are mixed nerves. The sensory cranial nerves are olfactory (smell), optic (vision) and acoustovestibular (hearing and balance) nerves.  The motor cranial nerves are trochlear (controls the superior oblique muscle of the eyeball), abducens (controls the lateral rectus muscle of the eyeball), accessory (controls the trapezius muscle in the back and shoulders), hypoglossal (controls the muscles of the throat and helps in swallowing) nerves.  The five mixed cranial nerves are occulomotor, trigeminal, facial, glossopharyngeal and vagus nerves.

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