Senses: Eye Flashcards
Light is detected by:
photoreceptors.
Name the difference spectrums of light:
Gamma rays X rays UV light visible light infared microwaves radio waves
Visible light ranges from (nm):
380nm to around 750nm.
What makes up color? Name the low and the high energy ends.
different wave lengths with in the visible light spectrum. (low - ROYGBIV - high). red has a longer wavelength
Opening in face that your eye is behind:
palpebral fissure
points of eye openings:
lateral and medial commissures
White of the eye:
sclera
pigmented part of eye:
iris
Eyelid is lined with a mucus membrane called the
conjunctiva
The photoreceptors on the retina are high dependent on:
blood flow from the vascular layer. for its nutrients and oxygen and so fourth.
Lacrimal apparatis:
tear glands
Tears get romoved by:
draining into the lacrimal canal which drains to the lacrimal sac, which dtrain through the nasolacrimal duct, which drains into the nasal cavity.
Eyes are controlled to muscles attached to the outside:
extrinsic muscles
We have 3 different cranial nerves controlling the different eye muscles.
trochlear nerve, abducens nerve, oculomotor nerve.
There are _ rectus muslces:
4 (rectus means straight). One on each of the 4 poles. superior, inferior, lateral, medial
there are _ oblique muscles.
- superior and inferior. They loop through a ring on the side and they twist your eyes.
Muscles inside the eye do two things:
opening of the pupil (iris) and control the thickness of the lens (ciliary body).
Define conjunctiva:
a transparent mucous membrane that lines the eyelids and covers anterior surface of eyeball except cornea.
a transparent mucous membrane that lines the eyelids and covers anterior surface of eyeball except cornea.
conjunctiva
What are the tunics?
the 3 layers that from the wall of the eye
Tunica fibrosa:
sclera and cornea (white, clear)
Tunica vasculosa:
choroid, ciliary body & iris (brown, pink)
Tunica interna:
retina (yellow)
space behind the cornea
anterior compartment
anterior compartment is made up of:
posterior chamber and anterior chamber
space posterior to the lens:
posterior compartment
The choroid is a muscle that’s attaches
the suspensory ligaments to the lens
Rods:
function in dim light. cannot see color
cones:
function in bright light and give you color information
light focuses directly on this portion of the retina:
macula lutea
the macula lutea has a little pit on it called the:
fovea centralis
the area where you have the highest concentration of cones, giving you the highest resolution:
on the fovea centralis (the pit in the macula lutea). H
highest rod concentration is where?
the peripheral areas of the retina
The optical components
are the inert non-neural components of the eye. They’re just sort of conduit for the light.
trace the path of light:
cornea, aqueous humor, then it hits the lens, then hits the vitreous body, retina
vitreous body is:
in the vitreous chamber and it presses the retina up against the choroid so that it stays alive.
glaucoma is when:
the aqueous humor builds up chronic high pressure in the eye. It can lead to eye damage eventually.
Neural components include what and do what?
they capture and process the information. includes: the retina, macula lutea, fovea centralis, optic disk
what is the optic disk:
where the optic nerve comes into the eye. its where all the neural info leaves the eye and where all the blood vessels enter the eye. no photoreceptor cells here (blind spot)
Fondus:
the inside rear of the eye
Macular degeneration:
it refers to damage and destruction to the macula lutea. people develop a black spot in the center of their vision.
Detached retina:
when the retina comes off the choroid. needs reattached or retina will die.
what part of neural tissue become the retinas:
the sides of the telencephalon.
motor output to the eye does what?
mainly involved i focusing the eye via changes in the lens. and it adjusts the pupil by acting on the iris of the eye.
Name 3 different things that cause an adjustment of the pupil
- changing light intensity
- changing focal distance
- emotional state and autonomic input
What two types of cells (muscles) change the pupil size?
sympathetic stimulation of pupillary dialator myoepithelial cells causes dilation of the pupil. they function kind of like a muscle.
parasympathetic reflex arc stimulates pupillary constrictor muscle, in response to light. both pupils constrict if one eye is illuminated.
refraction is:
the bending of light rays.
Two critical things that determine the bending of the light rays:
- incident angle
- relative densities of media (the greater the differences in density, the greater the bending of the light ray.)
Which refracts more light? cornea or lens?
the cornea refracts light more than the lens does. The lens fine-tunes the image, changing the shape to shift focus between near and distant objects. Thicker lens = more curvature than when its thin. So near light causes more bending via thicker lens because light is diverged more and needs to be adjusted more.
presbyopia:
your lens curvature doesn’t change
the image is inverted and backwards on your retina.
yea.
The near response occurs if the eyes:
focus on nearby objects
Covergence of eyes
eyes are pointing to something thats close up. essentially crossed. force is due to extrinsic muscles.
constriction of pupil is ___. aka ___.
it reduces the amount of light that goes around the edges of the pupil - aka pupillary miosis
accommodation of lens:
change the shape of the lens. nearby causes lens to be more convex (greater curvature). Light is refracted more strongly and focused onto retina.
What 3 things happen in a near response of the eye?
convergence of eyes.
constriction of pupil
accommodation of lens
extrinsic muscles of the eye are controlled by:
3 cranial nerves
Constriction of pupil and accommodation of lenses are ____
controlled via parasympathetic effects.
The condition where were looking at something far away:
emmetropia of the eyes
The condition where were looking at something close up:
convergence of the eyes.
Accommodation is due to what 2 things:
suspensory ligaments and the ciliary body
When the ciliary body contracts, the suspensory ligaments ___
the suspensory ligaments relax. this is when you’re looking at things up close
an opaque lens is commonly caused by___. When this happens, we have a condition that’s called ___.
UV light; cataracts
Hyperopia:
farsighted (eyeball too short).
How is hyperopia corrected?
corrected with convex lenses.
myopia:
nearsighted (eyeball too long)
How is myopia corrected?
corrected with concave lenses.
Nearsightedness is because:
eyeball too long
farsightedness is because:
eyeball too short
Rod cells:
don’t give color info, but are more sensitive to light. so they’re able to function in low light settings
Coe cells:
need more light to function. Functions in bright light and gives color information.
photoreceptors are modified:
modified cilia
the photoreceptor molecules are located where?
the outer segment. theres very extensive surface area here.
Rod’s outer segment looks like this:
stack of disks
cones outer segment looks like this:
a cone
outer segment is connected to inner segment via
stalk
inner segment of photoreceptor contains:
mitochondria
Endings of photoreceptor cells that release neurotransmitters are called:
outer fiber
Blood vessels of eye are located in the:
choroid
the outer segments of the rods and cones that absorb light are facing:
towards the choroid embedded in pigmented epithelium
Name the synapsing order starting with the photoreceptors
photoreceptors synapse on bipolar cells, which synapse on ganglion cells, which give rise to the axons that run through the optic nerve carrying the info to the brain.
ganglion cells also detect light, for what?
they detect it for our circadian rhythm, not for vision
the key to absorbing light is something called:___.
visual pigments
What are the 2 components of visual pigment molecules?
a protein called opsin & a vitamin A derivative called retinal
What changes the membrane voltage in the eye?
when the opsin and the vitamin A derivative called retinal detach and reattach.
Visual pigments are embedded where?
membrane of outer segments of rods and cones
