Vision Flashcards
Photo stimuli are electromagnetic waves between and ___ and ___ nm long
400 and 750
What part of the eye regulates the amount of light that comes into the eye?
Pupil
What controls the diameter of the pupil besides light?
Muscles in the iris
When light enters the eye the pupil dilates, what is another name for this?
Mydriasis
When the pupil constricts, what is the other name for it?
Mioisis
What makes up the optic apparatus of the eye?
Lens + Cornea
What determines the curvature of the lens?
Zonules + Ciliary muscles
What region of the eye is the fovea found in?
Macula
What is the inner cellular layer of the eye?
Retina
What kind of fluids is found in front of the lens?
Aqueous humor
What kind of fluids is found behind the lens?
Vitreous humor
Aqueous humor is continuously secreted by the _____ ______, while the vitreous humor is a stable ______ mass
ciliary process
gelatinous
Where specifically does the aqueous humor secrete between in the ciliary process?
Between the lens and iris (posterior chamber) thens through pupil into the space between iris and cornea (anterior chamber)
What kind of nutrients does the aqueous humor provide to the lens and cornea?
Glucose
Aqueous humor exits the eye through the ______ meshwork and ______ canal then drains into the ocular veins. Exits the eye through the _______ outflow pathway
trabecular
Schlemm’s
Uveoscleral
Intraocular pressure is maintained within the normal range of….?
15mmHg (+/-3mmHg)
High intraocular pressure causes what?
Glaucoma
How do you treat high intraocular pressure?
Increase aqueous humor drainage.
Use Latanoprost (prostaglandin-like)
What recycles the visual pigment molecules that are degraded using phototransduction?
Retina
What is the outermost layer of epithelial cells of the eye?
Non-neuronal retina (retinal pigment layer)
Of the retina, the outer segment faces the retinal pigment epithelium and has membrane folds called…? What does it contain?
disks
Rhodopsin
What does rhodopsin have?
Protein opsin and retinal (vitamin A derivatives)
Rods are (sensitive/not sensitive) to light and allow objects to be seen in (low/high) light intensity
sensitive
low
Cones are (sensitive/not sensitive) to light and allow objects to be seen in (low/high) light intensity
not sensitive
high
Highest density of cones are found in ….?
fovea
What are the three types of cone photoreceptors?
Blue (Short)
Green (Medium)
Red (Long)
In the dark, photoreceptors are depolarizing because…?
cGMP activates nonselective cation channels to open (Na+ influx), which causes release of glutamate
In the light, retina absorbs the photons and causes what?
11-cis-retinal to all trans retinal (conformational change in opsin and rhodopsin is activated). Opsin is associated w/ GTP binding protein called transducin
In the light, activation of transducin results in what?
Activation of PDE which degrades cGMP to 5’-GMP. The decrease in cGMP leads to closure of CNG channels
When light energy is converted into a receptor potential, receptor potential for rods and cones are (depolarizing/hyperpolarizing)
hyperpolarizing
In the light, closure of Na+ channels = ??? = reduction of ???? released
hyperpolarization
glutamate
Visual signals are transmitted into the superior portions of the ____ lobe and _____ posterior portions of the _____ lobe
occiptal
parietal
Visual signals representing color are transmitted mainly into the ______ visual cortex of the occipital lobe for further processing and interpretation
secondary
What degrades cGMP to 5’GMP?
PDE
The decrease in cGMP leads to closure of what?
CNG channels
What activates PDE enzymes to be released?
Activation of transducin
What activates the release of transducin?
Rhodopsin activating
