lecture 24 - pupillary reflexes and eye movements

Question 1

What are the brainstem nuclei involved with the oculomotor nerve?

Answer 1

Edinger-Westphal, Oculomotor

Question 2

What are the 6 key extraocular muscles that move the eye?

Answer 2

Superior/Inferior/Medial/Lateral rectus, Superior/Inferior Oblique

Question 3

Which extraocular muscles are supplied by the oculomotor nerve?

Answer 3

All rectus muscles except lateral, as well at the inferior oblique

Question 4

Which extraocular muscles are supplied by the trochlear nerve?

Answer 4

Superior oblique

Question 5

Which extraocular muscles are supplied by the abducens nerve?

Answer 5

lateral rectus

Question 6

Which cranial nerve supplies levator palpebrae superioris?

Answer 6

Oculomotor

Question 7

Which muscles facilitate activation of the lens in the eye?

Answer 7

Ciliary muscle

Question 8

Which nucleus is involved in the pupillary light reflex?

Answer 8

Edinger Westphal

Question 9

Which parasympathetic ganglion is involved in reflexes of the pupil?

Answer 9

Ciliary ganglion

Question 10

Which pupillary reflex requires cortical input?

Answer 10

Accomodation reflex

Question 11

What are the visible effects of a lower motor neuron lesions of the oculomotor nerve?

Answer 11

ptosis (inhibited eyelid opening), fixed/dilated pupils, inability to do eye movements

Question 12

Which cortical areas are involved in initiating eye movement?

Answer 12

Frontal eye field, occipital eye field

Question 13

What are the functions of the frontal eye field?

Answer 13

Voluntary, sudden movement of eyes to the side

Question 14

What are the functions of the occipital eye field?

Answer 14

Involuntary movements for fixation and tracking

Question 15

What structure lies between the cortical initiation centres and brain stem nuclei to facilitate eye movements?

Answer 15

Brainstem gaze centres, then to nuclei via medial longitudinal fasciculus

Question 16

What is the process of the light reflex, e.g. when light hits the left eye?

Answer 16

Light reachs left eye, afferent input is carried via optic nerve to the left and right Edinger Westphal nuclei (synapses with both), efferent signals carried from both EW nuclei to the pupillary constrictor muscles via the oculomotor nerves, the pupils constrict.

Question 17

What is the process of the accomodation reflex?

Answer 17

Blurred images reach the cortex, signal is relayed to the Edinger Westphal nucleus, signal is sent via the oculomotor nerve to the ciliary muscles, resulting in accomodation of the lens, and the eye muscles for medial deviation.