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41 Cards in this Set

  • Front
  • Back
List the steps of the pupillary light reflex
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
The axons of primary afferents that innervate the cornea travel in which nerve?
Where do they terminate?
Opthalmic (V1) div. of Trigeminal N
*Terminate in the spinal trigeminal nucleus
Which nerve innervates the Orbicularis oculi M?
Facial N (CN VII)
Describe the blink reflex if the left V1 is damaged and the left cornea is touched.
Neither eye will blink (no reflex)
Describe the blink reflex if the left CN VII is damaged and the left cornea is touched
Left eye will NOT blink (no reflex)
Right eye WILL blink

*Damage to CN VII prevents eyelid from blinking
What are the movements of the lateral and medial rectus muscles and which cranial nerves supply them?
Lateral rectus (CN VI) --> moves eye laterally (abduction)
Medial rectus (CN III) --> moves eye medially (adduction)
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?
Superior rectus --> upward
Inferior rectus --> downward
Superior oblique --> inward (intorsion)
Inferior oblique --> outward (extorsion)
If the eye is looking laterally, what are the effects of contraction of the superior/inferior rectus and oblique muscles?
Superior rectus --> elevation
Inferior rectus --> depression
Superior oblique --> inward (intorsion)
Inferior oblique --> outward (extorsion)
If the eye is looking medially, what are the actions of the superior/inferior rectus and oblique muscles upon contraction?
Superior rectus --> inward (intorsion)
Inferior rectus --> outward (extorsion)
Superior oblique --> depression
Inferior oblique --> elevation
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?
Saccades

*Can be voluntary or elicited by reflexes
What is the term for slow eye movements that track a target?
Are these movements voluntary or involuntary?
Smooth pursuit

*Involuntary
Which muscles are engaged in the horizontal gaze?
Medial and lateral rectus muscles
Which nucleus do the neurons in the Paramedian pontine reticular formation (PPRF) project to? What eye movements do these neurons control?
Abducens nuclei

*Control horizontal saccadic eye movements
Neuronal activity in which nucleus is necessary for the eyes to remain in a give position once the saccadic movement has occured
Nucleus prepositus hypoglossi
Which region of the brain is involved in voluntary saccadic eye movements?
Frontal eye field (Brodmann's area 8)

*Produce contralateral conjugate eye movements
Which region of the brain is primarily involved in reflexive saccadic eye movements?
Superior colliculus
Does the RIMLF function in verticle gaze or horizontal gaze?
Verticle
Which regions of the RIMFL are responsible for upward gaze and downward gaze?

Are these projections bilateral or ipsilateral?
Dorsal --> upward
Ventral --> downward

Projections that affect elevator muscles --> bilateral
Projects that affect depressor muscles --> ipsilateral
What is the role of the nucleus of the posterior commissure?
Contributes to vertical gaze
A lesion to the abducens nuclei will produce what type of gaze paralysis?
Horizontal gaze paralysis
*Inability of either eye to look toward the side of the lesion
What is the result of a lesion affecting the abducens nucleus or PPRF and the nearby MLF?
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
Damage to which regions will cause a vertical gaze palsy?
Posterior commissure and nearby regions
A lesion in which location will cause intranuclear opthalmoplegia (INO)?

What is the main feature of INO?
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
What are the 2 major causes of intranuclear opthalmoplegia?
1. Multiple sclerosis
2. Vascular problems
Do vergence movements require the MLF?
No.
In intranuclear opthalmoplegia (lesion of the MLF), vergence movements are usually preserved
If the left optic nerve is transected and a light is shined into the left eye, what will be the direct and consensual responses?
Direct response --> NONE
Consensual response --> NONE
If the left optic nerve is transected and a light is shined into the right eye, what will be the direct and consensual responses?
Direct response --> PRESENT
Consensual response --> PRESENT
If the left oculomotor nerve is transected and a light is shined into the left eye, what will be the direct and consensual responses?
Direct response --> NONE
Consensual response --> PRESENT
If the left optic nerve is transected and a light is shined into the right eye, what will be the direct and consensual responses?
Direct response --> PRESENT
Consensual response --> NONE
Which cranial nerves are involved in the pupillary reflex?
Sensory --> CN II
Motor --> CN III
Which cranial nerves are involved in the blink reflex?
Sensory--> CN V1
Motor --> CN VII
If the left Opthalmic N is transected and the left cornea is touched, what will be the direct and consensual reflexes?
Direct --> NONE
Consensual --> NONE
If the left Opthalmic N is transected and the right cornea is touched, what will be the direct and consensual reflexes?
Direct --> PRESENT
Consensual --> PRESENT
If the left Facial N is transected and the left cornea is touched, what will be the direct and consensual reflexes?
Direct --> NONE
Consensual --> PRESENT
If the left Opthalmic N is transected and the right cornea is touched, what will be the direct and consensual reflexes?
Direct --> PRESENT
Consensual --> NONE
In which part of the brain is the PPRF located?
Caudal pons
In which part of the brain is the Abducens nuclei located?
Caudal pons
In which part of the brain is the nucleus prepositus hypoglossi located?
Rostral medulla
In which part of the brain is the oculomotr nuclei located?
Midbrain
Which cranial nerves are involved in horizontal gaze?
CN III, VI
Which cranial nerves are involved in vertical gaze?
CN III, IV