GROSS ANATOMY
CRANIAL NERVES
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Oculomotor; controls most eye movements, pupil constriction, & upper eyelid rise
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Abducens; Abduction-moving laterally/ away from the midline
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Trochlear; Controls downward & inward eye movement
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Oculomotor; Controls downward & inward eye movement
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Detailed explanation-1: -The oculomotor nerve is the third cranial nerve (CN III). It allows movement of the eye muscles, constriction of the pupil, focusing the eyes and the position of the upper eyelid. Cranial nerve III works with other cranial nerves to control eye movements and support sensory functioning.
Detailed explanation-2: -The oculomotor nerve helps to adjust and coordinate eye position during movement. Several movements assist with this process: saccades, smooth pursuit, fixation, accommodation, vestibulo-ocular reflex, and optokinetic reflex. Saccades are rapid, jerky motions of the eye.
Detailed explanation-3: -Oculomotor nerve (III) is responsible for the control of the pupil (constriction) via parasympathetic fibres (this is opposed by dilator tone controlled by sympathetic pathways).
Detailed explanation-4: -Cranial nerves III (CNIII) (oculomotor), IV (trochlear), and VI (abducens) control the position of the eyeballs; CNIII influences the position of the eyelids and the size of the pupils.
Detailed explanation-5: -What are the functions of the oculomotor nerve? Nerve III controls muscles that turn eyeball up, down, and medially as well as controlling the iris, lens, and the upper eyelid.