11/5 Anatomy Flashcards
What controls the pupil diameter?
two opposing forces of dilation from the sympathetics; and constriction from CN III- Parasympathetics.
What would happen if you knock out CN III to the eye
it would dialate because you remove the parasympathetic innervation and only the sympathetic is left!
what gives general sensory info to the eye and face etc.
CN V (V-1 to the eye)
Describe the control of the retina reflex!! (the sensory, the motor)
Sensory is CN V-1 from cornea; Brainstem level pons CNS processing center; Motor CN VII (facial n. proper to orb occuli m.; consensual reflex (both eyes blink)
what cranial nerve senses light shined in your eye?
CN II
What CN would constrrict the eye when light is shined in?
CN III
CNIII lesion
eye moves down and out (only CNs IV and VI work); ptosis and midrisis
CN IV lesion
can not look in and down
CN VI lesion
double vision when looking laterally to side of lesion
The sphincter muscle of the face…to close the eye
Orbicularis oculi mucle
nerves of the Orbicularis oculi muscle
Facial nerve proper (CN VII)
the two muscles that keep the eyelid up:
levator palpegrae superioris muscle; Superior tarsal muscle
the nerve of the levator palpebrae superioris muscle:
Oculomotor nerve (CN III)
the nerve of the superior tarsal muscle:
sympathetics from T1 spinal cord!
what if I knock out the T1 sypathetics to the eye or the CNIII?
Ptosis: droopy eye-lid
How do I get sympathetics to the superior tarsal muscle?
pregaglionic nerve from T1 goes out ventral root, trunk, vetral ramus, white matter communicon, up the chain, synapse in the supperior cervical ganglion then wrap around the IJV and head into the head and along vessels to the eyes!
what is the gland in the supior lateral section above the eye?
Lacrimal gland
what is the funciton of the lacrimal apparatus/gland
Make tears!
Where do the tears drain?
dowy the sup./Inf. puncat and to the lacrimal canaliculli and to the lacrimal sac and to the nasolacrimal duct and to the nasal cavity!
what is the function of the tears?
to keep the eye from drying out, to wash it out and to help fight infection.
what innervates
the facial nerve CNVII - greater petrosal nerve.
describe the course of the greater petrosal nerve:
out the internal acoustic meatus with the facial nerve, then thorugh the greater petrosal hiatus, then towards the nose and through the pterygopalatine ganglion near the nasal cavity. then it jumps onto V-2 and then skips up to V-1 and then innervates the lacrimal gland!
waht are the layers of the eyeball?
the sclera/cornea; the choroid layer; the retina
What is the sclera?
the white of the eye: dense fibrous connective tissue
the transparent portion of the eyeball that is in front of the iris and the lens
The cornea
Function of the cornia
to refract in coming light
What innervates the cornea with sensory innervation
CN V-1
what are the components of the choroid layer of the eye?
ciliary muscle that connects to the suspen. ligaments; that connect to the lens. The ciliary muscle also connects to the iris!
what are the muslces that let more and less light into the eye?
the pupillary sphinctor muscles
how do we bend the lens
innervate the cilliary muscles and they contract and like any sphincter get closer together, and this loosens the suspensory ligaments and this will allow the lens to relax and form a more oval shape.
when do we need to innervate the ciliary muscles?
when trying to see something that is close to us, need more refraction to focus on retnia therefore need more oval lens and need loose suspensory ligament and contracted ciliary muscles!
at innervates the cilliary muscle?
parasympathetics from CN 3
what is the muscle that makes the pupil diameter smaller?
the sphincter pupillae muscle that is around the edge of iris
what innervates the shincter pupillae?
the CN III
what is the path to innervate the shincter pupillae muscle?
along the CNIII to the ciliary ganglion to synapse and send post-synaptic to the sphincter pupillae to cause it to contract
what muscle dialates the pupil?
the pupil dialator muscle
what innervates the pupil dialator muscle?
the sympathetic nerves that also innervate the superior tarsal muscles.
describe the path to innervate the dilator pupillae and the superior tarsal muscles
the sypmatetics from the T1 and through the supeior cervical gangleon travel up the IJV to the skull to hop along what ever nerve possible to get to the eye.
What if we innerupt sympathetic innervation to the head?
Horner’s syndrome!
what is the symptoms of Horners?
P.A.M. Ptosis, Anhydrosis, and Miosis [droopy eye-lid; flush; pupil diameter smaller. “P.A.M has Horners”
what is the origin and course of the CN II
from the olfactory receptors in the nasal cavity, through little holes called the cribiform foramina and then synapse in the olfactory bulb and tract.
What is the clinical finding of knocking out CN I?
Anosmia: don’t smell
The course of CNII
from the retina, through the optic canal, to the optic chasim, and then some will be ipsolateral, some will cross over or decicate and go controlateral to the optic tract to the occiptial lobe.
What if you knock out the CNII
blind and lose the pupillary light reflex.
what are CN I and II extensions of?
the telencephalon and diencephalon respectively.
what do CN III, IV, and VI all have in common?
they innervate the extra-occular muscles
what is the course of the CN III
Arise from the midbrain and course through the cavernous sinus to the superior orbital fissure; and then to innervate extra–occular muscles and parasympatheitcs of the lens and pupil
what does the CNIII do?
SM: Inferior Oblique muscle; SM: Inferior rectus muscle; SM: Medial recuts; SM: superior rectus muscle and SM: levator palpebrae superioris muscle; AND VM: puplillary constrictor muscle and VM: cilliary muscles
Course of the CN IV
froml the midbrain through the cavernous sinus to the superior orbital fissure and to the superior oblique
the pully of the superior oblique motor
Trochlea
innervated by the CN IV
the superior oblique muscle
The course of the Abducens nerve (CN VI)
from the pons to the cavernous sinus to the superior orbital fissure and innervate the lateral rectus.
what is abduction of the eye?
movement to the lateral or the outside (abduct is to take away!)
What is adducted
towards the midline
what is the up and down movement o fhte eye?
elevation and deprestion
what is the pivotal movements of the eye?
intorsion and extorsion!
what muscle will abduct the eye
The lateral rectus
what muscle will adduct the eye?
The medial rectus
what action would the Superior rectus muscle have?
up and in since the vecor is at an angle of 23 degrees with the face back and
what action would the Inferior oblique have?
up and out.
What would be the action of the Inferior rectus muscle?
down and out
what would be the action of the superior oblique
down and out
what are the clinical testing of the muscles in the “H”
medial recuts medial then up to the IO, down to the SO, then lateral to the LR, and up to the SR and donw to the IR
what is the innervation of the eye muscles
“LR6SO4R3”
how to test the superior rectus muslce?
line the eye up with the muscle and then up…so adduct the eye and elevate.
how to test the IO muscle?
line the eye up with the muscle…so abduct the eye and then elevate
how to test eh SO?
adduct the eye and then down
how to test the IR
abduct the eye and look down.
