Orbital Autonomics Flashcards

1
Q

where do sympathetic nerve fibres for the eye leave the spinal cord?

A

T1 spinal nerve

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2
Q

where do sympathetics for the eye synapse?

A

the superior cervical sympathetic ganglion

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3
Q

where do post synaptic sympathetic axons for the eye enter after they synaose?

A

the internal and external carotid nerves which pass onto the carotid arteries

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4
Q

what carries the sympathetic axons into the orbit?

A

the ophthalmic artery

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5
Q

where do all parasympathetic axons leave the CNS?

A

cranial nerves 3,7,9 and 10 OR via sacral spinal nerves

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6
Q

what parasympathetic ganglion supplies the eye?

A

the ciliary ganglion

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7
Q

what cranial nerve contributes to the ciliary ganglion?

A

CN III

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8
Q

where is the ciliary ganglion located?

A

the bony orbit

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9
Q

what is CN III?

A

the oculomotor nerve

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10
Q

where does CN III connect with the CNS?

A

the junction of the midbrain and the pons

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11
Q

where does CN III exit the cranial cavity?

A

the superior orbital fissure

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12
Q

what two modalities does CN III carry?

A

somatic motor

parasympathetic

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13
Q

what does CN III carry somatic motor nerve to?

A

the majority of the extraocular muscles

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14
Q

what are the two divisions of CN III after it passes through the superior orbital fissure, and which is then part of the ciliary ganglion?

A

superior

inferior - this one

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15
Q

what supplies sensory innervation of the face?

A

the branches of the trigeminal nerve

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16
Q

where does the trigeminal nerve originate?

A

the lateral surface of the pons

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17
Q

what is another name for the corneal reflex?

A

blinking

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18
Q

what type of reflex is the corneal reflex?

A

sensory

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19
Q

what is the function of the corneal reflex?

A

to protect the eye

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20
Q

what are the three components of the corneal reflex?

A

sensory (afferent)
central
motor (efferent)

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21
Q

what happens in the sensory limb of the corneal reflex?

A

AP’s conducted from the cornea via CN V1 and taken to the trigeminal ganglion

travels along CN V to the pons

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22
Q

what are the central CNS connections involved in the corneal reflex?

A

connections between CN V and CN VII

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23
Q

what happens in the motor limb of the corneal reflex?

A

AP’s conducted from the brain via CN VII

to the palpebral part of orbicularis oculi = a blink

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24
Q

what does the vestibulo-ocular reflex do?

A

turns the eye in the opposite direction to head movement, to stabilise gaze

25
Q

what are the CNS connections in the VOR?

A

between CN 7 and CN’s 3,4 and 6

26
Q

what is the oculocardiac reflex?

A

when reflex bradycardia occurs in response to tension on extraocular muscles or pressure on the eye

27
Q

what are the CNS connections in the oculocardiac reflex?

A

between CN V1 and CN X

28
Q

what happens to the eyes in the sympathetic response?

A

open wider to get more light in
focus on far objects
emotional lacrimation

29
Q

what happens to the eyes in the parasympathetic response?

A

get less light in
focus on near objects
reflex lacrimation

30
Q

what two muscles are involved in opening the eyes wider?

A

levator palpebrae superioris (LPS)

mueller’s muscle

31
Q

what does the LPS do?

A

raises the upper eyelid

32
Q

what muscle type is found in the LPS?

A

skeletal and smooth

33
Q

what is another name for mueller’s muscle?

A

superior tarsus muscle

34
Q

where is the mueller’s muscle attached?

A

LPS

35
Q

what type of muscle is mueller’s muscle and what innervates it?

A

smooth

sympathetics

36
Q

what is the function of mueller’s muscle?

A

elevates the eyelid by an additional 2mm

37
Q

what effect does parasympathetic stimulation have on the pupil?

A

constricts

38
Q

what muscles are involved in the constriction of the pupil?

A

sphincter pupillae muscles - contract

39
Q

what effect does sympathetic stimulation have on the pupil?

A

dilates

40
Q

what muscle is involved in the dilation of the pupil?

A

dilator pupillae

41
Q

what is another name for a non-physiologically enlarged pupil?

A

mydriatic

42
Q

what is another name for a non-physiologically constricted pupil?

A

miotic

43
Q

what makes up the sensory limb of the pupillary light reflex?

A

CN II on the side light is shone in

44
Q

where do the CNS connections for the pupillary light reflex occur?

A

the midbrain

45
Q

what makes up the motor limb of the pupillary light reflex?

A

CN III on both sides

46
Q

where does the suspensory ligament of the lens attach?

A

the ciliary body

47
Q

what type of muscle is found in the ciliary body?

A

smooth

48
Q

what type of vision causes the ciliary body to relax?

A

far vision

49
Q

what happens when the ciliary body relaxes?

A

suspensory ligament of the lens tightens and the lens flattens

this allows the eye to focus on distant objects

50
Q

what type of vision causes the ciliary body to contract?

A

near vision

51
Q

what happens when the ciliary body contracts?

A

suspensory ligament of the lens relaxes and the lens becomes spherical

this allows the eye to focus on near objects

52
Q

what are the three different types of tears produced by the eyes?

A

basal
reflex
emotional

53
Q

when are basal tears produced?

A

all the time

54
Q

what is the function of basal tears?

A

clean and hydrate the cornea

55
Q

what immune component is found in basal tears?

A

lysozyme

56
Q

when are reflex tears produced?

A

in response to mechanical or chemical stimulation

57
Q

what is the afferent limb for production of reflex tears?

A

CN V1 from the cornea and conjunctiva

58
Q

what is the efferent limb for the production of reflex tears?

A

parasympathetic axons from CN VII

59
Q

when are emotional tears produced?

A

due to an emotion e.g. sad, scared