Lecture 52 - Ocular Structure 1 Flashcards
in dogs, what bones comprise the orbit?
Frontal
Lacrimal
Maxillary
Sphenoid
Zygomatic
Palatine
what bone is present in the equine orbit but not the dogs’
temporal instead of maxillary
what is retrobulbar disease
tumor/abscess development behind the globe which pushes the globe forward
what is the job of the retractor bulbi mm.
pulls the eye back (caudally)
what is the job of the dorsal rectus mm.
rotates globe upward
what is the job of the ventral rectus mm.
rotates globe downward
what is the job of the medial rectus mm.
rotates globe medially
what is the job of the lateral rectus mm.? what innervates it?
rotates globe laterally
abducens
what is the job of the dorsal oblique mm.? What innervates it?
rotates dorsal globe medially and ventrally
trochlear
what is the job of the ventral oblique mm.
rotates ventral globe medially and dorsally
what innervates the retractor bulbi mm.
abducens
what is strabismus
deviation of the eye due to damage to oculomotor mm.
explain the bulbar conjunctiva
sits over the globe itself
explain the palpebral conjunctiva
sits on the eyelid
explain the conjunctival fornix
creates a pocket to keep things out of the body cavity between the bulbar and palpebral
what are the 3 layers of the tear film
- lipid layer
- aqueous layer
- mucoid layer
describe the drainage system of the lacrimal system
- lacrimal puncta
- canaliculi
- nasolacrimal duct
- nasal punctum
what is a Jones Test?
used to test the lacrimal drainage system
what are the 3 layers of the globe
- fibrous tunic
- vascular tunic
- neural layer
what is within the fibrous tunic
cornea and sclera
what is the main difference between conjunctiva and sclera
the conjunctiva is a thin translucent membrane whereas the sclera is the thick, white CT
what is within the vascular tunic
iris, ciliary body, and choroid
the components of the vascular tunic are often referred to as
uvea
what is within the neural layer
retina and optic nerve
what is the anterior chamber
contains aqueous humor, between the cornea and lens
what is the posterior chamber
contains aqueous humor, sits between the ciliary and lens
what is the vitreous chamber
contains vitreous humor (gel) sits behind the lens
what is contained in the anterior segment of the globe
- cornea
- iris
- ciliary body
- lens
- anterior & posterior chamber
what is contained in the posterior segment of the globe
- choroid
- retina
- optic nerve
- vitreous chamber
what does this structure look like on histology:
orbicularis oculi m.
elongated/tubular cells
peripherally located nuclei
what facial nerves are in charge of the palpebral reflex
CN V (sensation) and CN VII (motor)
what is the tarsal plate
sheet of dense connective tissue that maintains structural integrity and shape of eyelids
Describe meibomian glands
sebaceous glands within the tarsal plate
produces meibum (lipid) component of tear film
what does this structure look like on histology:
conjunctiva
stratified columnar epithelium with goblet cells
describe the third eyelid
- protects and lubricates the eye
- produces aqueous component of tears
- secondary lymphoid organ
what are the 4 layers to the cornea
- epithelium
- stroma
- descemet’s membrane
- endothelium
what is the importance of the corneal endothelium
pumps aqueous humor out of the corneal stroma
what cranial nerves are involved in the corneal reflex
CN V (sensation)
CN VI (motor to retractor bulbi)
CN VII (motor to eyelids)
describe the dilator muscles of the iris
smooth mm.
sympathetic innervation
describe the constrictor muscles of the iris
smooth mm.
parasympathetic innervation
what are zonular fibers
connective tissue protein that secures the lens in the optical axis
where is the origin of zonular fibers and aqueous humor
ciliary body
what are the non-pigmented ciliary body epithelium responsible for
production of aqueous humor
what is the iridocorneal angle and what is the clinical significance
space between the iris and ciliary body anteriorly
responsible for the outflow of aqueous humor (glaucoma)
describe the anterior lens epithelial cells
progenitors for new lens fibers and regulates lens homeostasis
T/F: no lens epithelial poles are found in the posterior pole
TRUE
Describe the fundus
inside, black surface if the eye containing the retina, choroid, tapetum lucidum, and blood vessels
____ receives and organizes visual stimuli and ____ transmits sensory to neural info
retina; optic nerve
