Anatomy: Autonomic Pathways and Eye Reflexes

Question 1

Organs in the head and neck with autonomic innervation

Answer 1

Skin
Eyes
Lacrimal Glands
Saliva Glands

Question 2

Skin Autonomic Innervation

Answer 2

Sympathetic innervation of arteriole, sweat glands and arrestor muscles

Question 3

Eyes autonomic innervation

Answer 3

Smooth muscle of iris (pupil diameter)

Smooth muscle of the ciliary body associated with the lens (focussing)

Question 4

Lacrimal Glands Autonomic Innervation

Answer 4

Lacrimal fluid production

Question 5

Saliva Glands autonomic innervation

Answer 5

Saliva production

Question 6

Sympathetic innervation: route

Answer 6

originates from autonomic centres in the brain.
passes down spinal cord
Exits spinal cord with T1-L2 region (thoracolumbar outflow)
Travel to sympathetic chains running length of vertebral column
Pass into all spinal nerves (anterior and posterior rami)
Pass into splanchnic nerves to eventually supply organs

Question 7

Presynaptic sympathetic axons from CNS

Answer 7

Exit spinal cord in T1 spinal nerve
Ascend within sympathetic chain
Synapse in superior cervical sympathetic ganglion

Question 8

Post-synaptic sympathetic axons

Answer 8

Enter internal and external carotid arteries.
Carried to the organs of the head on the surface of the branches of these arteries
ophthalmic artery carries sympathetic axons into the orbit.

Question 9

Parasympathetic Axons exit CNS

Answer 9

Leave the CNS via cranial nerves III, VII, IX and X and sacral spinal nerves

Craniosacral outflow

Question 10

Parasympathetic Supply

Answer 10

Internal organs, not body wall

In head
- eye, lacrimal gland and salivary glands

Question 11

Vagus nerve

Answer 11

Supples organs of the neck, chest, abdomen as far as the midgut

Question 12

Sacral spinal nerves

Answer 12

Carry parasympathetic axons to the handout, pelvis and perineums

Question 13

Ciliary ganglion

Answer 13

parasympathetic ganglion
Located in bony orbit
Fibres from CN III

Question 14

Cranial nerve III

Answer 14

Oculomotor
Connects with CNS at junction of midbrain and pons
passes through cavernous sinus
Exits via superior orbital issues

Somatic motor to majority of extra ocular muscles

presynaptic parasympathetic axons to the ciliary ganglion

Question 15

Sensory innervation: face

Answer 15

CN V1 (ophthalmic nerve) 
CN V2 (maxillary nerve)  
CN V3 (mandibular nerve)

Question 16

CN V1 innervates

Answer 16

Upper eyelid
Cornea
Conjunctiva

Question 17

CN V2 innervates

Answer 17

Skin of lower eyelid

Skin over the maxilla

Question 18

CN V3 innervates

Answer 18

Skin over mandible and TMJ (except angle of mandible)

Question 19

Corneal Reflex

Answer 19

Blink

Question 20

Corneal Reflex Afferent Limb

Answer 20

Sensory (afferent) limb

Action potentials conducted from cornea via CN V1 branches to trigeminal ganglion.
Then along CN V to pons

Question 21

Corneal Reflex Efferent Limb

Answer 21

Motor (Efferent) limb

Action potentials conducted via CN VII to eyelid part of orbiculares oculi

Question 22

Autonomic Reflexes of Eye (5)

Answer 22

Wide eye opening of fight or flight
Pupillary light reflex 
Accommodation Reflex 
Vestibula-ocular reflex 
Oculocardiac Reflex

Question 23

Vestibule-ocular reflex

Answer 23

Turns the eye in the opposite direction to a head movement

Stabilizes gaze on an object during head movement

Question 24

Vestibule-ocular reflex Cranial nerves

Answer 24

CNS connections between CN VIII and CN III, IV and VI

Question 25

Oculocardiac Reflex

Answer 25

Reflex bradycardia in response to tension on extra ocular muscles or pressure on eye

Question 26

Oculocardiac Reflex cranial nerves

Answer 26

CNS connections between CN VI and CN X

Question 27

Wide Eye Opening Reflex

Answer 27

Levator palpebrae superioris (controlled by CN III) - Contains skeletal muscle plus smooth muscle - Muellers muscle

Question 28

Muellers Muscle

Answer 28

used during wide eye opening reflex to elevate the eyelid by a further 2cm under sympathetic innervation

Question 29

Postsynaptic sympathetic fibres travel via... (4)

Answer 29

Superior cervical sympathetic ganglion internal carotid nerve internal carotid plexus Axons carried on ophthalmic artery and on its branches to orbital structures

Question 30

Pupillary Constriction

Answer 30

Parasympathetic constrict the pupil - in bright light and 'rest and digest' Sphincter pupilae fibres encircle pupil around the internal circumference of iris

Question 31

Miotic pupil

Answer 31

non-physiologically constricted pupil e.g. components off Horner's syndrome

Question 32

Fixed 'pin point' pupil

Answer 32

Often a serious pathological sign e.g. opiate drugs

Question 33

Fixed 'dilated' pupil

Answer 33

also called a blown pupil often a serious pathological sign E.g. CN III pathology

Question 34

Pupillary dilation

Answer 34

Sympathetic innervation dilates the pupil

Question 35

Mydriatic pupil

Answer 35

Non-physiologically enlarged pupil e.g. mydriatic drugs induce dilation of pupil

Question 36

Dilator Papillar Fibres arrangment

Answer 36

Radially arranged Originate around the external circumference of iris - fixed insert around the internal circumference of iris -mobile

Question 37

pupillary light reflex

Answer 37

Special sensory (afferent) limb of the reflex is the ipsilateral CN II (optic) CNS connections occur in the midbrain Motor (efferent) limb of the reflex is bilateral via CN III

Question 38

Light reflex- bilateral

Answer 38

Direct light reflex occurs in the stimulated eye Consensual light reflex occurs in the. non-stimulated eye

Question 39

Pupillary Light Reflex Neurones

Answer 39

``` 1st neurones 2nd Neurones (bilateral) 3rd neurones (bilateral) 4th neurones (bilateral ```

Question 40

Lens Accommodation Reflex

Answer 40

Suspensory ligament of lens connects the circumferences of the lens and the ciliary body

Question 41

Ciliary body

Answer 41

Muscular and vascular | Smooth muscle like a sphincter around circumference

Question 42

Ciliary muscle- 'far vision'

Answer 42

Relaxes - no parasympathetics Ligaments tighten and lens flattens to focus on an object in the distance

Question 43

Ciliary muscle - 'near vision'

Answer 43

Contracts -parasynmpathetic Ligament relaxes and lens become spherical to focus on near objects

Question 44

Clinical assessing components of accommodation reflex (3)

Answer 44

Bilateral pupillary constriction - parasympathetic constriction of sphincter pupillae Bilateral convergence of both eyes towards midline - medial rectus Bilateral relaxation of lens - lens becomes spherical due to contraction of ciliary muscles

Question 45

Cranial nerve for lens accommodation. reflex

Answer 45

CN III (oculomotor)

Question 46

Lacrimation (3)

Answer 46

basal tears Reflex tears Emotional tears

Question 47

basal tears

Answer 47

Corneal health Clean/nourish and hydrate vascular cornea Contains lysozyme 9hydrolyses bacterial cell walls)

Question 48

Reflex tears

Answer 48

Extra tears in response to mechanical or chemical stimulation Afferent limb in Cn V1 from cornea/ conjunctiva Efferent limb is psaarasympathetic axons originating from CN VII

Question 49

Emotional tears

Answer 49

happy, sad or frightened