Question

Which one of the following cranial nerves is carrying the nerve fibres originating from the Edinger-Westphal nucleus?
A. Oculomotor
B. Trochlear
C. Abducens
D. Vagus

Answer 1

Hint: Cranial nerves are a part of the Peripheral Nervous System. The peripheral nervous system is subdivided into the somatic neural system and the autonomic nervous system. There are twelve pairs of cranial nerves in man.

Complete answer:
Edinger-Westphal nucleus is located near the level of the superior colliculus in the midbrain, positioned immediately dorsal to the oculomotor nucleus. The other two-lobed of the corpora quadrigemina are present on the lower side and are called the inferior colliculi. Sensory impulses are received from the eyes and muscles of the head to the superior pair of colliculi and control visual reflexes. They control and coordinate the movement of the head and eye at the same time to fix and focus on an object.
Oculomotor is a motor cranial nerve that starts from the floor of the midbrain in the Edinger-Westphal nucleus and distributes in the eye and the four muscles of the eyeball. It controls the movements of the eyeball, iris, lens, and eyelid.
Trochlear is a motor cranial nerve originating from a pair of trochlear nuclei within the midbrain at the level of the inferior colliculus and distributes to the eye and superior oblique muscles of the eyeball. Its main function is the rotation of the eyeball.
Abducens: It originates from Pons of the hindbrain and distributes to the external rectus muscle of the eyeball. It is a motor cranial nerve and helps in the rotation of the eyeball.
Vagus (Pneumogastric): It is a sensory as well as motor cranial nerve which arises from the side of the medulla and distributes to the muscles of the pharynx, vocal cords, lungs, heart, esophagus, stomach, and intestine.

Therefore, the answer is (A) Oculomotor.

Note:
- Vagus nerve helps in the movement of vocal cords, respiratory reflexes, peristaltic movements, speech, swallowing, secretion of gastric glands, slows down the heartbeat, and lung movements.
- Other cranial nerves are Olfactory, Optic, Trigeminal, Facial, Auditory, Glossopharyngeal, spinal accessory, and hypoglossal.