Eye Flashcards
what is a conjunctiva
a transparent mucous membrane that lines
eyelids and covers anterior surface of eyeball, except cornea
what do tears help with
help to wash away foreign particles, deliver
O2 and nutrients, and prevent infection with a bactericidal lysozyme
where do tears flow through
flow through lacrimal punctum (opening on edge of each eyelid)
to the lacrimal sac, then into the nasolacrimal duct emptying into
nasal cavity
what are the eye muscles
superior, inferior, medial, and lateral rectus, and superior and inferior obliques
what are the three principal components of the eyeball
the three tunics, the neural component, and the optical component
what is the tunica vasculosa
middle vascular layer
what is the tunica fibrosa
outer fibrous layer
what is the tunica interna
retina and beginning of optic nerve
what releases the aqueous humor
ciliary body
what reabsorbs the aqueous humor
scleral venous sinus
what is a cataract
the clouding of the lens caused by age, diabetes, smoking, drugs, etc
what is glaucoma
elevated pressure within the eye due to obstruction of scleral venous sinus and improper drainage of aqueous humor
when does pupil constriction and dilation occur
when light intensity changes or when our gaze shifts between distant and nearby objects
what is emmetropia
state in which the eye is relaxed and focused on an
object more than 6 m (20 ft) away
what are the 3 adjustments for the near response
convergence of eyes, constriction of pupil, and accommodation of lens
what is hyperopia and what eye shape is it?
farsightedness, short eye
how do you fix farsightedness?
convex lens
what is myopia and what eye shape is it?
nearsightedness, long eye
how do you fix nearsightedness?
concave lens
what do rod cells help with?
night vision, scotopic vision, or
monochromatic vision
what is the outer segment of rod cells?
modified cilium specialized to absorb light
what is the inner segment of rod cells?
contains organelles sitting atop cell body with nucleus
what do cone cells do?
color, photopic, or day
vision
what pigment do cone cells have?
phodopsin
