Autonomics Of The Eye And Orbit

Question 1

Preganaglionic neuron cell body of sympathetic nervous system

Answer 1

T1-L2

Question 2

Postganglionic neuron of sympathetic

Answer 2

Close by in the sympathetic chain

-longest fiber

Question 3

NT for sympathetic

Answer 3

Epi/norepi

Question 4

Where do all of the head and neck sympathetic synapse?

Answer 4

Superior cervical ganglion

Question 5

Preganglionic nerve cell body in parasympathetic

Answer 5

Brainstem or sacral spinal cord

-long

Question 6

What are the parasympathetic cranial nerves

Answer 6

3,7,9,10

Question 7

Where is the postganglionic cell body in parasympathetic

Answer 7

In a ganglion near the target organ

Question 8

Length of parasympathetic postganglionic fibers

Answer 8

Short

Question 9

What is the NT of parasympathetic

Answer 9

Ach

Question 10

Ocular structures innervated by the autonomic nervous system

Answer 10

• iris muscles (iris sphincter and iris dilator muscles)
• ciliary muscles
• smooth muscles of the eyelids (Mullers Muscle)
• choroidal and conjunctival blood vessels
• lacrimal glands

Question 11

What are the main parasympathetic CN that innervate the eye

Answer 11

3,7

Question 12

Where does the sympathetic nervous system originate

Answer 12

In the lateral gray column of the thoracic and upper lumbar segments of the spinal cord

Question 13

Where doe sympathetic innervation for ocular structures originate?

Answer 13

Segments T1-T3

Question 14

Where does the parasympathetic innervation of ocular structures originate

Answer 14

In the midbrain and pons (CN III and VII)

Question 15

Where is the preganglionic neuron of the efferent pathway located of the ANS

Answer 15

In the brain or spinal cord

Question 16

Where is the cell body of the second neuron in the ANS efferent pathway located

Answer 16

In a ganglion outside the CNS

Question 17

Where does the preganglionic fiber of the ANS efferent pathway terminate?

Answer 17

Myelinated, terminates in an autonomic ganglion, where synapse occurs

Question 18

Where does the postganglionic fiber of the ANS efferent pathway go

Answer 18

Nonmyelinated

-exits the ganglion and innervates the target structure

Question 19

Sympathetic ganglia usually are located __________, whereas parasympathetic ganglia are located ________

Answer 19

• near the spinal column

- near the target structure

Question 20

Ocular structures supplied by the sympathetic system

Answer 20

Iris dilator
Ciliary muscle
Smooth muscle of lids
Lacrimal gland
Choroidal and conjunctival blood

Question 21

Ocular structures innervated by the parasympathetic

Answer 21

Iris sphincter
Ciliary muscle
Lacrimal gland
Blood vessels

Question 22

What is the main difference between the structure that are innervated by the parasympathetic and the sympathetic

Answer 22

Iris muscles

Question 23

Where do the sympathetic preganglionic fibers synapse that are going to ocular structures

Answer 23

Superior cervical ganglion

Question 24

What do the postganglionic sympathetic fibers do after they leave the superior cervical ganglion?

Answer 24

• form the carotid plexus and the internal carotid artery

- and enter the skull through the carotid canal

Question 25

How do the network of fine sympathetic fibers destined for ocular structures leave hte plexus?

Answer 25

In the cavernous sinus and take multiple pathways to the target structures

Question 26

Where do all postganglionic sympathetic fibers go before they branch off to where they need to go?

Answer 26

Cavernous sinus

Question 27

What is the first sympathetic pathway

Answer 27

Some travel with the ophthalmic division of trigeminal nerve -once in orbit, they follow the nasociliary nerve, then travel with the long ciliary nerves to innervate the iris dilator and the ciliary muscle

Question 28

What is the second sympathetic pathway

Answer 28

- other fibers follow same as #1 to nasociliary nerve and then branch to the ciliary ganglion as the sympathetic root - these pass through ciliary ganglion without synapsing. Enter globe as the short ciliary nerves to innervate the choroidal blood vessels

Question 29

What innervates the choroidal blood vessels

Answer 29

Short ciliary nerves

Question 30

What is the pathway to the conjunctival vasculature through?

Answer 30

May be through either the long or shirt ciliary nerves

Question 31

What is the 3rd sympathetic pathway in the ocular structures

Answer 31

- others fibers join the oculomotor nerve and go into orbit to innervate the smooth muscle of the upper eyelid (Mullers) - follow same path as superior division of CN III as it supplies the levator muscle

Question 32

What innervates the smooth muscle of the upper eyelid (Mullers muscle)

Answer 32

CN III

Question 33

Alternate route to mullers muscle

Answer 33

From the infratrochlear or lacrimal nerve has been suggested but not confirmed

Question 34

Activates the iris dilator, causing pupillary dilation and thereby increasing retinal illumination

Answer 34

Sympathetic

Question 35

Causes vasoconstriction of the choroidal and conjunctival vessels

Answer 35

Sympathetic

Question 36

Widens the palpebral fissure by stimulating the smooth muscle of the eyelids (mullers muscle)

Answer 36

Sympathetic

Question 37

Exhibits a small inhibitory effect on the ciliary muscle

Answer 37

Sympathetic

Question 38

What size are pupils when you sleep

Answer 38

Tiny

Question 39

Where is the preganglionic neuron in the parasympathetic pathway to the intrinsic ocular muscles located?

Answer 39

In the midbrain in the parasympathetic accessory third nerve nucleus, also called the ending ER-westphal nucleus

Question 40

What happens to the preganglionic parasympathetic neuron fibers going to ocular structures after it leave the nucleus?

Answer 40

With the motor fibers of the oculomotor nerve and follow the inferior division of that nerve into the orbit -they leave the inferior division and enter the ciliary ganglion as the parasympathetic root

Question 41

Where do the parasympathetic preganglionic fibers synapse that are headed to ocular structures?

Answer 41

Ciliary ganglion

Question 42

Where is the ciliary ganglion located

Answer 42

Within the muscle cone between the lateral rectus muscle and the optic nerve, approximately 1cm anterior to the optic canal

Question 43

What are the three roots located at the posterior edge of the ciliary ganglion?

Answer 43

1. parsympathetic root 2. Sensory root, carries fibers from globe and joins with nasociliary nerve 3. Sympathetic root, which supplies the blood vessels

Question 44

What kind of fibers synapse in the ganglion

Answer 44

Parasympathetic

Question 45

What do the short ciliary nerves located at the anterior edge of the ciliary ganglion carry?

Answer 45

1. Sensory 2. Sympathetic 3. Parasympathetic fibers

Question 46

How do the postganglionic parasympathetic fibers exit the ganglion

Answer 46

In the short ciliary nerves, enter the globe, and travel to the anterior segment of the eye to innervate the sphincter and ciliary muscles

Question 47

What do most of the parasympathetic fibers that enter the globe through the shirt ciliary nerves innervate

Answer 47

The ciliary body

Question 48

Parasympathetic stimulation causes _____________, thus decreasing retinal illumination and reducing chromatic and spherical aberrations

Answer 48

Pupillary constriction

Question 49

Parasympathetic stimualtion causes __________ enabling the eye to focus on near objects in accommodation

Answer 49

Contraction of the ciliary muscle

Question 50

The iris contains muscles innervated by

Answer 50

Both autonomic systems

Question 51

The PNS and SNS nerves are in some state of balance in the normal, healthy, awake individual, and the size of the pupil changes constantly and rhythmically, reflecting this balance, this is called what

Answer 51

Pupillary unrest called hippus

Question 52

Pupils during sleep

Answer 52

Small because the SNS shuts down and the PNS predominates

Question 53

The efferent autonomic pathway to the lacrimal gland

Answer 53

Lacrimal nucleus---facial nerve----grater petrosal nerve----Vivian nerve----pterygopalatine ganglion----maxillary nerve-----zygomatic nerve-----lacrimal nerve----lacrimal gland

Question 54

Fibers controlling the parasympathetic innervation originate in the pons in an area within the nucleus for cranial nerve VII designated as the

Answer 54

Lacrimal nucleus

Question 55

Preganglionic fibers from the lacrimal nucleus exit the pons with the motor fibers of the facial nerve and enter

Answer 55

The internal auditory canal, and pass through the geniculate ganglion of the facial nerve without synapsing

Question 56

How do the parasympathetic fibers to the lacrimal gland leave the geniculate ganglion of the facial nerve?

Answer 56

S the greater petrosal nerve, which exits the petrous portion of the tmpeoral bone

Question 57

What is the Vivian nerve

Answer 57

The greater petrosal nerve is joined by the deep petrosal nerve, composed of sympathetic postganglionic fibers from the carotid plexus

Question 58

Where does the Vivian nerve go once it is formed?

Answer 58

Enters the pterygopalatine ganglion, where the parasympathetic fibers synapse, sympathetic fibers pass through without synapsing

Question 59

What do the autonomic fibers do once they leave the pterygopalatine ganglion?

Answer 59

Join with the maxillary branch of the trigeminal nerve, pass into the zygomatic nerve and then form a communicating branch to the lacrimal nerve Alternate pathway bypasses the zygomatic nerve and travels from the ganglion directly to the gland

Question 60

The parasympathetic fibers that innervate the lacrimal gland are of the secretomotor type and thus

Answer 60

Increase secretion

Question 61

Sympathetic innervation of lacrimal gland

Answer 61

Sympathetic fibers innervate the blood vessels of the gland and might indirectly cause decreased production of lacrimal gland secretion by restricting blood flow

Question 62

Sympathetic fibers to the lower eyelid

Answer 62

Sympathetic fibers from the zygomatic nerve also branch into the lower eyelid and innervate mullers muscle of the lower lid (opens eye larger)

Question 63

Reflex tearing

Answer 63

Irritation of any branch of the trigeminal nerve activates a reflex afferent pathway, precipitating increased lacrimation

Question 64

Corneal touch initiates the three part corneal reflex

Answer 64

1. Lacrimation 2. Miosis (shrinking pupil) 3. Protective blink Done by interneurons, no cerebral processing