Anatomy - Important Reflexes of the Orbital Region Flashcards Preview

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Flashcards in Anatomy - Important Reflexes of the Orbital Region Deck (35)
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1

Sensory innervation of the face is as a result of which nerve?

Trigeminal nerve (CN V)

2

Which regions of the face does the opthalmic nerve provide sensory innervation to?

  1. Upper eyelid
  2. Cornea
  3. Conjunctiva
  4. Skin of root/bridge/tip of nose

3

Which regions of the face does the maxillary nerve nerve provide sensory innervation to?

  1. Skin over lower eyelid
  2. Skin over maxilla
  3. Skin over ala of nose
  4. Skin/mucosa of the upper lip

4

Which regions of the face does the mandibular nerve provide sensory innervation to?

  1. Skin over mandible*
  2. Skin over TMJ

(*Excludes angle of mandible)

5

What is the function of the blink/corneal reflex?

Protects eye

6

Describe the path of a sensory action potential during the blink/corneal relfex

  1. Cornea via CN V1 branches
  2. Trigeminal ganglion
  3. CN V
  4. Pons

7

During the blink/corneal relfex, which nerve carries the motor response?

CN VII

(to eyelid part of orbicularis oculi)

8

Sympathetic axons can exit the spinal cord between whcih levels?

T1-L2

9

Where can sympathetic signals pass?

  1. Up/down sympathetic chain
  2. Spinal nerves via anterior/posterior rami
  3. Splanchnic nerves

10

Where do presynpatic sympathetic axons synapse?

Superior cervical sympathetic ganglion

11

How do post-synaptic sympathetic axons travel to organs in the head?

Via internal and external carotid arteries

12

Parasympathetic axons leave the spinal cord via which nerves?

  1. Cranial nerves III, VII, IX and X
  2. Sacral spinal nerves

13

Where does the oculomotor nerve connect with the CNS?

Junction between midline and pons

14

Where does the oculomotor nerve enter the orbit?

Superior orbital fissure

(via cavernous sinus)

15

What does the oculomotor nerve supply?

Somatic motor to:

  1. Superior rectus (superior division)
  2. Levator palpebrae superioris (superior division)
  3. Medial rectus (inferior division)
  4. Inferior rectus (inferior division)
  5. Inferior oblique (inferior division)

It also innervates the ciliary ganglion (inferior division)

 

16

What is the function of ciliary nerves?

Supply autonomic axons to control iris diameter and refractive shape of lens

17

What types of innervation do long ciliary nerves provide?

  1. Somatic sensory
  2. Sympathetic (to dilator pupillae muscle)

18

What types of innervation do short ciliary nerves provide?

  1. Sympathetic
  2. Parasympathetic (ciliary body and iris)

19

What are the main autonomic reflexes of the eye?

  1. Maximal eyelid elevation (fight or flight)
  2. Pupillary dilation/constriction (light reflex)
  3. Focussing lens far and near (accomodation reflex)
  4. Tear production (lacrimation reflex)
  5. Turns eyes in opposite direction to head movement to maintain gaze (vestibulo-ocular reflex)
  6. Reflex bradycardia in response to tension on extraocular muscles or pressure on eye (oculocardiac reflex)

20

The sympathetic system functions to focus on _____ objects

The sympathetic system functions to focus on far objects

21

Which muscle is involved in widening the eyes during sympathetic stimulation?

Levator palpebrae superioris

(contains both skeletal and smooth muscle)

22

Which branch of the autonomic nervous system will dilate the pupil?

Sympathetic

23

Which types of drugs dilate the pupil?

Mydriatic drugs

24

Which muscle will dilate the pupil?

Dilator pupillae muscle

25

What is the term used to describe a non-physiologically constricted pupil?

Miotic

26

Which muscle is responsible for constricting the pupil?

Sphincter pupillae muscle

27

The pupillary light reflex involves a _-neurone chain

The pupillary light reflex involves a 4-neurone chain

28

Describe the pathway of the neurones involved in the pupillary light reflex

  1. Optic nerve
  2. Synapse in midbrain
  3. Pass (via 2nd neurone within midbrain) and synapse in Edinger-Westphal nucleus
  4. CN III inferior division
  5. Synpase in ciliary division
  6. Coarse in short ciliary nerves to sphincter pupillae muscles

29

When does the the ciliary muscle contract?

Under parasympathetic stimulation

(To focus on near vision)

30

What are the three components of the accomodation reflex?

  1. Bilateral pupillary constriction
  2. Bilateral convergence of both eyes towards to midline
  3. Bilateral relaxation of the lens