Nsp Week 3: Eye Movements And Reflexes (Blair)

Front 1

List the steps of the pupillary light reflex

Back 1

1. Retina
2. Optic nerve
3. Optic chiasm
4. Optic tract
5. Pretectal nucleus in the dorsal midbrain
6. Edinger-Westphal nucleus
7. Oculomotor nerve
8. Ciliary ganglion
9. Sphincter (circular) muscle of iris

Front 2

The axons of primary afferents that innervate the cornea travel in which nerve?
Where do they terminate?

Back 2

Opthalmic (V1) div. of Trigeminal N
*Terminate in the spinal trigeminal nucleus

Front 3

Which nerve innervates the Orbicularis oculi M?

Back 3

Facial N (CN VII)

Front 4

Describe the blink reflex if the left V1 is damaged and the left cornea is touched.

Back 4

Neither eye will blink (no reflex)

Front 5

Describe the blink reflex if the left CN VII is damaged and the left cornea is touched

Back 5

Left eye will NOT blink (no reflex)
Right eye WILL blink

*Damage to CN VII prevents eyelid from blinking

Front 6

What are the movements of the lateral and medial rectus muscles and which cranial nerves supply them?

Back 6

Lateral rectus (CN VI) --> moves eye laterally (abduction)
Medial rectus (CN III) --> moves eye medially (adduction)

Front 7

If the eye is looking straight ahead, what are the PRIMARY effects of contraction of the superior & inferior rectus muscles, and superior & inferior oblique muscles?

Back 7

Superior rectus --> upward
Inferior rectus --> downward
Superior oblique --> inward (intorsion)
Inferior oblique --> outward (extorsion)

Front 8

If the eye is looking laterally, what are the effects of contraction of the superior/inferior rectus and oblique muscles?

Back 8

Superior rectus --> elevation
Inferior rectus --> depression
Superior oblique --> inward (intorsion)
Inferior oblique --> outward (extorsion)

Front 9

If the eye is looking medially, what are the actions of the superior/inferior rectus and oblique muscles upon contraction?

Back 9

Superior rectus --> inward (intorsion)
Inferior rectus --> outward (extorsion)
Superior oblique --> depression
Inferior oblique --> elevation

Front 10

What is the term for rapid eye movements that are used typically to change the point of visual fixation?
Are these movements voluntary or involuntary?

Back 10

Saccades

*Can be voluntary or elicited by reflexes

Front 11

What is the term for slow eye movements that track a target?
Are these movements voluntary or involuntary?

Back 11

Smooth pursuit

*Involuntary

Front 12

Which muscles are engaged in the horizontal gaze?

Back 12

Medial and lateral rectus muscles

Front 13

Which nucleus do the neurons in the Paramedian pontine reticular formation (PPRF) project to? What eye movements do these neurons control?

Back 13

Abducens nuclei

*Control horizontal saccadic eye movements

Front 14

Neuronal activity in which nucleus is necessary for the eyes to remain in a give position once the saccadic movement has occured

Back 14

Nucleus prepositus hypoglossi

Front 15

Which region of the brain is involved in voluntary saccadic eye movements?

Back 15

Frontal eye field (Brodmann's area 8)

*Produce contralateral conjugate eye movements

Front 16

Which region of the brain is primarily involved in reflexive saccadic eye movements?

Back 16

Superior colliculus

Front 17

Does the RIMLF function in verticle gaze or horizontal gaze?

Back 17

Verticle

Front 18

Which regions of the RIMFL are responsible for upward gaze and downward gaze?

Are these projections bilateral or ipsilateral?

Back 18

Dorsal --> upward
Ventral --> downward

Projections that affect elevator muscles --> bilateral
Projects that affect depressor muscles --> ipsilateral

Front 19

What is the role of the nucleus of the posterior commissure?

Back 19

Contributes to vertical gaze

Front 20

A lesion to the abducens nuclei will produce what type of gaze paralysis?

Back 20

Horizontal gaze paralysis
*Inability of either eye to look toward the side of the lesion

Front 21

What is the result of a lesion affecting the abducens nucleus or PPRF and the nearby MLF?

Back 21

One-and-a-half syndrome
*the ipsilateral eye loses all of its horizontal movements, but the contralateral eye loses only half of its horizontal movements-- it can still move laterally

Front 22

Damage to which regions will cause a vertical gaze palsy?

Back 22

Posterior commissure and nearby regions

Front 23

A lesion in which location will cause intranuclear opthalmoplegia (INO)?

What is the main feature of INO?

Back 23

A lesion to the medial longitudinal fasciculus (MLF) between the abducens and oculomotor nuclei

*Inability to adduct one eye during attempted horizontal gaze. The unaffected eye often exhibits nystagmus during the attempted movement

Front 24

What are the 2 major causes of intranuclear opthalmoplegia?

Back 24

1. Multiple sclerosis
2. Vascular problems

Front 25

Do vergence movements require the MLF?

Back 25

No.
In intranuclear opthalmoplegia (lesion of the MLF), vergence movements are usually preserved

Front 26

If the left optic nerve is transected and a light is shined into the left eye, what will be the direct and consensual responses?

Back 26

Direct response --> NONE
Consensual response --> NONE

Front 27

If the left optic nerve is transected and a light is shined into the right eye, what will be the direct and consensual responses?

Back 27

Direct response --> PRESENT
Consensual response --> PRESENT

Front 28

If the left oculomotor nerve is transected and a light is shined into the left eye, what will be the direct and consensual responses?

Back 28

Direct response --> NONE
Consensual response --> PRESENT

Front 29

If the left optic nerve is transected and a light is shined into the right eye, what will be the direct and consensual responses?

Back 29

Direct response --> PRESENT
Consensual response --> NONE

Front 30

Which cranial nerves are involved in the pupillary reflex?

Back 30

Sensory --> CN II
Motor --> CN III

Front 31

Which cranial nerves are involved in the blink reflex?

Back 31

Sensory--> CN V1
Motor --> CN VII

Front 32

If the left Opthalmic N is transected and the left cornea is touched, what will be the direct and consensual reflexes?

Back 32

Direct --> NONE
Consensual --> NONE

Front 33

If the left Opthalmic N is transected and the right cornea is touched, what will be the direct and consensual reflexes?

Back 33

Direct --> PRESENT
Consensual --> PRESENT

Front 34

If the left Facial N is transected and the left cornea is touched, what will be the direct and consensual reflexes?

Back 34

Direct --> NONE
Consensual --> PRESENT

Front 35

If the left Opthalmic N is transected and the right cornea is touched, what will be the direct and consensual reflexes?

Back 35

Direct --> PRESENT
Consensual --> NONE

Front 36

In which part of the brain is the PPRF located?

Back 36

Caudal pons

Front 37

In which part of the brain is the Abducens nuclei located?

Back 37

Caudal pons

Front 38

In which part of the brain is the nucleus prepositus hypoglossi located?

Back 38

Rostral medulla

Front 39

In which part of the brain is the oculomotr nuclei located?

Back 39

Midbrain

Front 40

Which cranial nerves are involved in horizontal gaze?

Back 40

CN III, VI

Front 41

Which cranial nerves are involved in vertical gaze?

Back 41

CN III, IV