Lecture 9 (DONE) Flashcards
What spectrum does visible light fall on?
390nm - 750 nm
What are some other waves on the electromagnetic spectrum?
Gamma rays, X-rays, UV rays, radar, FM, TV, shortwave, and AM
Which way do photoreceptors face and why?
Backwards towards the vasculature. This is because they need the most nutrients due to it needing to turn light in to neural signals
What does light do in the outer segment of the photoreceptors?
Light is absorbed by pigment in outer segment of rods and cones and triggers phototransduction.
What are the functions and description of cones?
*Day vision
*Operate at high levels
*Color Vision
*High spatial resolution
*Very Dense in Fovea
What are the functions and description of RODS?
*Night vision
*Operate at low levels
*Absent in fovea
*Low spatial resolution
What are photons?
Particles of energy, emitted from atoms, that travel in space as a wave.
How do we see objects?
The sun emits lights that is reflected off an object.
What are the thee major neuron types in the retina?
Photoreceptors, Bipolar cells, Retinal ganglion cells
What do the axons of the RGC leave the eye to form?
The optic nerve.
What are photoreceptors in the retina?
First neurons in the visual chain that respond to light and make up images of an object in the retina.
What are visual pigments?
They absorb light which result in a change in the membrane protection.
What does the outer segment of rods and contain?
Visual pigment
What is phototransduction?
The process in which light is turned in to a neural signal.
Why are cones high resolution and why are rods low resolution?
Cones to bipolar cells are a 1 to 1 ratio wheraas rods connect to bipolar cells making them not spatially accurate.
What is the projection for the eye to the visual cortex?
Retina to LGN to Visual Cortex
What is your blind spot?
A point in your vision where you cannot see anything. It is where the optic nerve is.
What is the purpose of visual pigment?
Visual pigment absorbs lights, which results in a change in the membrane potential.
What is one example of your cone vision failing?
For the constellation called Pleiades, it’s like 7 stars. They are very dim stars. If you focus on them with your fovea, they’ll disappear. Because there’s not enough light to activate your cones. And you have to look at the right of them just so your rods are activated. Then you can see the stars.
Why do rods have many connections compared to 1:1 in cones?
It is because rods work the best at night. So they want to take that very small amount of light and they want to make sure that the signal gets to the brain. So they start pooling all their inputs, so you get a bigger signal.
How do signals from the eye go back to your brain?
