15.1 Flashcards
In the eye is parasympathic or sympathetic responsible for pupil size decreasing?
Parasympathetic
In the eye is parasympathic or sympathetic responsible for pupil size increasing?
Sympathetic
Which part of the eye contains the photosensitive neural layer of the eye?
The Retina
Rods or Cones
Dim light, peripheral vison receptors
rods
Rods or cones
vision receptors for bright light
cones
rods or cones
more numerous and more sensitive to light
rods
no color vision or sharp images
rods
high resolution color vision
cones
Numbers greatest at periphery
rods
Outer segment of photoreceptors are made of..
flattened plasma membrane
What is the term for the light sensitive molecule
chromophore
WHat is protein plus vitamin A dervived chromophore
Rhodopsin
Term for when a single photon (light particle) that causes entire protein to change shape
Isomerized
What is retinal originally derived from
B carotene
In retinal synthesis what happens after its isomertized by light
must be recycled by multi step enzymatic process that occurs partly in photoreceptor cells and partily in support (pigmented) cells
Which part of the eye contains mostly cones
macula
Which part of the eye contains all cones
Fovea centralis
Which part of the eye is responsible for the best vision
Fovea Centralis
Where is the cone density highest in
central vision
Which type of vision is rod density the greatest
peripheral vision
What is the cause of Glaucoma
pressure and pinching of the optic nerve
Which eye disease is caused by blocked drainage of aqueous humor increases pressure and causes compression of retina and optic nerve which eventually leads to blindness
Glaucoma
Clouding of the eye is referred to as
Cataracts
What eye disease is caused by crystalline proteins clump
Cataracts
Why do cataracts prevent eyesight
light cannot travel through the lens as well
Which is worse wet or dry AMD?
Wet
The fovea centralis is the center of what
macula
Rhodopsin is made from what
a G Protein Coupled Receptor
What are the four cells that vision works through
Photoreceptor to Bipolar to Retinal Ganglion to Brain
Do rods or cones have high sensitivity and function in dim light
rods
Do rods or cones have high acuity
Cones
Are there more rods or cones?
rods
Are rods or cones in peripheral retina
rods
Are rods or cones mostly in central retina
cones
B Carotene is involved in which process
Pigment synthesis
Isomerization is also known as
photoactivation
Enzymatic Regeneration is done where
partly in Retinal Pigment Epithelium cells
In phototransduction iare ion channels open or closed in response to light
closed
What are the five steps in phototransduction
light, receptor, g protein, enzyme and 2nd messenger
What are G Proteins powered by
GTP
In the dark are CNG channels open or closed
open
In the light are photorecepters on or off
off
In the light are CNG channels open or closed
closed
In the dark are photoreceptors on or off
on
In the dark when is GABA released
Constantly
In the light when is GABA released
Never
In the dark is the bipolar cell on or off
off
In the light are the biopolar cells on or off
on
In the dark are the Retinal Ganglion cells on or off
off
In the light are retinal ganglion cell on or off
on
What does the ciliary muscle do
changes the shape of the lens
how does the ciliary muscle change the shape of the lens
contraction looses the ciliary zonule fibers and relation tightens them
WHat shape is the lens in for distant vison
flat
What shape is the lens in for close vision
bulges
myopic is the term for
nearsighted
hyperopic eye is a term for
farsighted
myopic or nearsighted is because the eyeball is what
too long
What does intrinsically photosensitive do
signals directly to circadian centers
Which color eye has the most melanin
brown
