Science Section 3 Flashcards
When do you become aware of external stimulus
Only when the stimulus make its way up to the cerebral cortex that you become aware
What is phototransduction
when a receptor is activated by its preferred stimulus, the receptor is cell is depolarized leading to an action potential and or transmitter release
What cells transmit information out of the eye via action potentials potentials via their long axons
Retinal Ganglion Cells
Where is the blind spot in the eye
The point of where all these axons come together to exit out of the eye
What is the center of retina?
The center of the retina is called the fovea
What does the pupil do?
It the part of the eye that can dilate and contract to let light in
What functions do the pigmented epithelial cell have?
It has many functions as absorbing excess light, so it does not scatter and blur the images. and getting rid of the old, broken down segments of the photo receptors cells.
What are the two general photoreceptor cells
Rod & cones
How many cones are in cone systems are in a primate
There are three cones (Trichromantic) system
What do photoreceptor cells do when depolarized?
Release nuerotransmitter glutamate
why is the optic nerve considered a blind spot?
There are no photoreceptors there and no light can be transduced from this spot in the retina
Where do all the axons of the retinal ganglion cells come together?
The optic nerve
Amacrine cells can…
distribute information from one bipolar cell to many ganglion cells
Horizontal cells…
form connections between one central rod or cone to many other more distant photoreceptors and between several bipolar cells
Lateral Inhibition
refers to the capacity of excited neurons to reduce the activity of their neighbors, happens when a photoreceptor depolarizes a horizontal cell and the horizontal cell acts to inhibit the more distant bipolar cells
center-surround receptive fields
When neurons in the retina become stimulated, the neurons can choose to sharpen edges and enhance contrast in the images, creating clarity in the image
purpose of center-surround receptive fields
sharpen edges and enhance contrast in the images by amplifying the edges and borders
retinal edges in the fovea are very…
small, the horizontal cell connects fewer retinal ganglion cells to a single photoreceptor allowing highly acute vision
receptive fields in the peripheral parts f the retina are..
large and reduce less sharp vision
Once light has been transduced and processed the retinal ganglion cells…
transmit that information out the eye via action potentials down their long axons
retinofugal pathway
lating for feeling, the axons of the retinal ganglion exit at the back of the eye making up the optic nerve, and go all the ay back to the thalamus and then to the visual areas of the cerebral cortex
Optic chasim
the point where axons from both eyes come together as the cross targeting the thalamus on the opposite side of the head, named after the Greek letter “chi” which looks like an “X”
optic tract
the bundles of axons after reaching the optic chiasm, used to distinguish from the optic nerve
Left vs Right
Information about the left side of the world reaches the right side of the brain and vise versa