Important Reflexes of the Orbital Region Flashcards

1
Q

what parts of the eye does the opthalmic nerve (CNV1) supply?

A

upper eyelid
cornea
conjunctiva

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2
Q

what parts of the eye does the maxillary nerve (CNV2) supply?

A

lower eyelid

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3
Q

sensory nerve to the face?

A

trigeminal

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4
Q

only part of the face not to be supplied by the trigeminal nerve?

A

spinal nerves C2 + 3

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5
Q

describe the route a sensory afferent takes when you need to blink

A

from cornea to CNV1 branch

goes via trigeminal ganglion to pons

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6
Q

describe the route a motor efferent takes when you need to blink

A

action potentials conducted by CN 7

go to eyelid part of orbicularis oculi

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7
Q

how do sympathetic nerves of the eyes reach them?

A

exit at T1 of the symp chain
head up the chain alongside carotid arteries
synapses at the superior cervical ganglia
carried to the orbit by opthalmic artery

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8
Q

parasympathetic axons supply the body: T or F

A

F

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9
Q

what foramen does cn 3 exit via?

A

superior orbital fissure

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10
Q

what do the ciliary nerves do?

A

control diameter of iris

control refractive shape of lens

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11
Q

most important cranial nerve for parasympathetic innervation of the eye?

A

CN3

CN7 is also important

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12
Q

what makes up the short ciliary nerve?

A

inferior division of CN3

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13
Q

what makes up the long ciliary nerve?

A

CNV1

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14
Q

what type of ciliary nerve is responsible for parasympathetic innervation of the eye

A

short

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15
Q

what is the name of the reflex that causes you to blink when something is coming close to you?

A

accommodation reflex

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16
Q

what is the vestibulo-ochlear reflex?

A

eyes turn an opposite way to the head to focus on an object

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17
Q

which autonomic type allows the eye to focus on far objects and which allows you to focus on near objects?

A
near= parasympathetic
far= sympathetic
18
Q

which autonomic nerves are responsible for reflex lacrimation?

A

parasympathetic

19
Q

what controls smooth muscle?

A

autonomic nervous system

20
Q

how is the sympathetic nervous system able to open the eyes wider even if you dont want them to?

A

there is smooth as well as skeletal muscle in the levator palpebrae superioris

21
Q

name the muscle and autonomic nerves responsible for pupillary dilatation

A

dilator pupillae muscles

sympathetic

22
Q

what is a mydriatic pupil?

A

a non-physiologically enlarged pupil

23
Q

where do the dilator pupillae muscles attach?

A

around the iris circumference

24
Q

what nerves control pupillary constriction

A

parasympathetics

25
Q

cause of a fixed pin point pupil?

A

opiate drugs

26
Q

cause of a fixed dilated pupil?

A

cn3 pathology

27
Q

what nerves control the sensory and motor part of the pupil light reflex?

A
sensory= optic
motor= oculomotor
28
Q

what happens to the other eye when light is shone in one eye?

A

it should constrict

29
Q

why do pupils constrict when exposed to light?

A

to stop excess light damaging the retina

30
Q

how many neurones are in the pupillary light reflex chain?

A

4

31
Q

name the synaptic locations of each of the neurones of the pupillary light reflex chain

A
  1. pretectal nucleus in midbrain
  2. EW nucleus
  3. ciliary ganglion
32
Q

what is the ciliary body?

A

a sphincter controlling the lens of the eye

33
Q

the ciliary muscle is not innervated by any parasympatheitc nerves: T or F

A

F

34
Q

does the ciliary muscle contract in near or far vision?

A

near

35
Q

what nerves cause the relaxation of the lens?

A

sympathetic

36
Q

what nerves cause the contraction of the lens?

A

parasympathetic

37
Q

what happens to eyesight when the lens is contracted?

A

focuses on far sight

38
Q

how are tears antimicrobial?

A

contain lysozyme that hydrolyses bacterial cell walls

39
Q

afferent and efferent limbs of the lacrimal reflex?

A

CNV1 from cornea= afferent

parasympathetics from CN7= efferent

40
Q

symptoms of horners syndrome?

A
miosis
ptosis
reduced sweating
increased warmth
redness