Term
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Definition
keep eyes moist
prevent scratches fom external forces |
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Term
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Definition
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Term
| In comparison to regular hair, eyelashes are |
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Definition
| more sensitive than other hair |
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Term
| Name the glands in between the eyelashes. |
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Definition
tarsal gland
ciliary gland |
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Term
| What is the purpose of the tarsal gland and ciliary gland? |
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Definition
| produce lubricants to keep eyelids from sticking together |
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Term
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Definition
| blockage of a tarsal or ciliary gland |
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Term
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Definition
| membrane that lines the eyelids and anterior surface of the eyeball, except for the cornea |
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Term
| What part of the eyeball does the conjunctiva not cover? |
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Definition
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Term
| What is the purpose of the conjunctiva? |
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Definition
| protection and lubrication |
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Term
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Definition
| pink eye, caused by infection, very contagious, causes inflamation of the eye |
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Term
| What is the lacrimal apparatus? |
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Definition
| part of eye that is made of glands and tear ducts. |
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Term
| Where are tears made and secreted? |
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Definition
| In the ducts of the larcrimal in the upper lateral part of the eye. They run across the eye towards the nose. |
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Term
| The tears run into the nose? |
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Definition
| through the nasolacrimal duct |
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Term
| Name the 6 extrensic eye muscles. |
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Definition
superior rectus
inferior rectus
medial rectus
lateral rectus
inferior oblique
superior oblique |
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Term
| What two muscles move the eye lids? |
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Definition
| orbicularis oculi and levator palpebrae superioris |
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Term
| What are the two basic eye movements? |
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Definition
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Term
| _____ ______ are among the most precisely and rapidly controlled skeletal muscles in the body. |
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Definition
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Term
| Where is aqueous humor stored? |
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Definition
| between the cornea and lens |
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Term
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Definition
| a clear, gel-like material stored behind the lens |
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Term
| What are the three tunics of the eye? |
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Definition
Outer, fibrous, cornea & sclera
Middle, vascular, choroid
Inner, sensory, retina |
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Term
| Which part of the tunic is avascular? |
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Definition
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Term
| Sclera: what is it, where is it, what is its function? |
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Definition
White part of eye
Fibrous Tunic
eye muscles anchor to it |
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Term
| Cornea: what is it, where is it, what is its function? |
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Definition
clear part of the eye that bends light so helps focus
it is in the fibrous tunic |
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Term
| The cornea is largely made out of ________, but it is lined on both surfaces with ________ tissue |
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Definition
collagen
epithelial tissue |
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Term
| Why do the epithelial layers of the cornea have sodium pumps? |
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Definition
| they pump sodium ions across cornea, water follows it by osmosis. the water keeps the cornea compact-no over hydrating, swelling or loosing transparency |
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Term
| From where does the cornea get nutrients and oxygen? |
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Definition
|
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Term
| What are the components of the middle vascular tunic? |
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Definition
| choroid, ciliary body and Iris |
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Term
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Definition
| highly vascular part of the vascular tunic, it is brown, deeply pigmented it absorbs stray light. |
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Term
| What is the ciliary body? |
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Definition
a thickened extension of the choroid, forms a muscular ring around the lens. Supports the iris and lens and secretes aqueous humor.
Maintains the shape of the lens. |
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Term
| What shapes of muscle fibers are in the Iris? |
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Definition
Circular fibers
radial fibers |
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Term
| What happens when the circular fibers of the iris contract? |
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Definition
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Term
| What happens when the radial fibers of the iris contract? |
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Definition
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Term
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Definition
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Term
| What are the problems associated with complete albanism and eyes. |
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Definition
| No pigment in eyes, look pink, have low vision, hard to get light to focus on eye and have bad depth perception |
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Term
| What are the components of the sensory tunic? |
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Definition
|
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Term
| how is the retina held to the back of the eye? |
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Definition
|
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Term
| What is the fovea centralis? |
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Definition
| a tiny pit in the middle of the macula lutea that produces the most finely detailed images |
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Term
| What is the macula lutae? |
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Definition
| a patch of cells directly posterior to the center of the lens on the visual patch of the eye |
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Term
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Definition
| Where the optic nerve leaves the rear (fundus) of the eye. |
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Term
| What is the blind spot of the eye? |
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Definition
| the optic disc where there are no rods and cones |
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Term
| What is retinal detachment and how does it happen? |
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Definition
Retinal detachment is a disorder of the eye in which the retina peels away from its underlying layer of support tissue. Initial detachment may be localized, but without rapid treatment the entire retina may detach, leading to vision loss and blindness.
Traumatic injury and the natural reduction of vitreous humor associated with aging |
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Term
| What are photoreceptor cells? |
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Definition
| cells that absorb light and generate a chemical or electrical signal, rods and cones |
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Term
| Which photoreceptor is black and white sensitive, most useful at night? |
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Definition
|
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Term
| How many rods are in the retina and where are they? |
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Definition
| 100 million, all over the eye |
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Term
| How many cones are in the eye and where are they located? |
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Definition
| 3 million, mostly in the macula lutea |
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Term
| ________ are the photoreceptors most useful during the day. |
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Definition
| Cones, they need bright light to work |
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Term
| What are the photoreceptors that interpret color? |
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Definition
|
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Term
| What are the three types of cones. |
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Definition
| red, green and blue types |
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Term
| Color blindness is X linked so it is more common in _____. |
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Definition
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Term
| Why you can see is because you break down _______ in rods and cones. |
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Definition
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Term
| Why you can see is because you break down _______ in rods and cones. |
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Definition
|
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Term
| What is neural convergence in the retina? |
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Definition
| it occurs where multiple rods or cones synapse with on bipolar cell and again where the multiple bipolar cells feed into one ganglion cell |
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Term
| What are the steps in light activation? |
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Definition
light->ganglion layer->bipolar cell layer->photoreceptors
the photoreceptor layer, bipolar layer, and horizontal layer, then the optic nerve. This is also the order that they "fire" Hope that makes sense!
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Term
| Name the photoreceptor pigments. |
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Definition
|
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Term
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Definition
| visual pigment of the rods. |
|
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Term
| list the steps for signals being sent to the brain through rods |
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Definition
light->rhodopsin=>retinal and opsin
opsin->other moleules->neurotransmitter release->signals sent to brain |
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Term
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Definition
| photoreceptor pigment in the cones, 3 types one for red, one for green and one for blue |
|
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Term
| what causes colorblindness? |
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Definition
| if you are missing one or more types of iodopsins |
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Term
| What are the functions of aqueous humor and how is it formed? |
|
Definition
function: nourishes cornea and lens and removes waste
formed: by ciliary process in the ciliary body on a continual basis. Drains by the canal of schlemm. |
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Term
| What are the functions of vitreous humor and how is it formed? |
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Definition
holds retina in place and helps eyeballs keep shape
Formed during fetal period, no more is made after birth |
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Term
| The _____ can change shape to allow precise focusing of light on the retina. |
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Definition
|
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Term
| what are the two regions of the lens? |
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Definition
lens epithelium on outside layers
lens fibers in inside, made out of protein and it is clear |
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Term
| What are the focusing features of the eye? |
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Definition
|
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Term
| What is vision accommodation? |
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Definition
| the eye making adjustments from far to near vision (far is considered normal state) |
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Term
| What are the three parts of vision accommodation? |
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Definition
lens shape change (by suspensory ligaments in the ciliary body)
Pupils constrict
Eyeballs converge, have to focus on same image at same time. |
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Term
| can you look someone directly into the eyes? |
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Definition
| no, can only look at one eye because of convergence |
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Term
| What is myopia and how is it treated? |
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Definition
nearsightedness, eyeball is longer than normal distance; distant objects focus in front of retina (hard to see far away objects)
Corrected with a concave lens l( |
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Term
| What is Hyperopia and how is it treated? |
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Definition
farsightedness, can't see objects close, eyeball is too short, near objects focus behind the retina
correct with convex lens () |
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Term
| What is astigmatism and how is it treated? |
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Definition
abnormal irregularities of the cornea or lens, where light is scattered so does not focus evenly on the retina
correct with glasses or contacts |
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Term
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Definition
inability of aqueous humor to drain via the canal of Schlemm, causing high pressure on eyeball. Increase pressure decreased blood supply to retina and optic nerve, cells in structures may die causing blindness
treated with eye drops then if needed surgery |
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Term
|
Definition
| inability to distinguish to a full range of colors. Usually caused by deficient number in a particular type of cone. Trouble distinguishing between red and green is often inherited b/c linked to X recessive trait. |
|
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Term
| What is cortical blindness? |
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Definition
| Cortical blindness is the total or partial loss of vision in a normal-appearing eye caused by damage to the visual area in the brain's occipital cortex.[1] This damage can be caused by loss of blood flow to the occipital cortex from hypoxia, meningitis, head trauma, hydrocephalus. Color vision often intact. CVI for child neurologically like adult learning to knit while walking a tightrope. |
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Term
| What is thermokeratoplasty? |
|
Definition
| heat shaping of the cornea |
|
|
Term
| What is radial keratotomy? |
|
Definition
|
|
Term
| what do contact lenses do? |
|
Definition
| temporarily reshape the cornea |
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Term
|
Definition
30 minutes before-numbing drops
laser cust flap in cornea, it's reshaped, flap laid down, no stitches
vision can fluctuate up to 6 months |
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