Vision Flashcards
1
Q
Cornea
A
- front of eye
- clear, dome-like structure that allows light to enter into eye
- gathers and focuses incoming light
2
Q
Pupil
A
light for cornea enters this gap in the iris
3
Q
Iris
A
- color portion of the eye
- regulates size of pupil with its contractile muscles – smaller iris = larger pupil and vice versa
4
Q
What happens to pupil when exposed to bright light?
A
- pupil will constrict to protect retina
- involuntary muscles in iris relax
5
Q
What happens to pupil in the dark?
A
- pupil will dilate to get more light into retina
- involuntary muscles in iris contract
6
Q
Lens
A
- located behind the iris
- focuses/refracts light to create a focal point
7
Q
Fovea
A
- focal point of light located at the back of the eye
- only cones located here, no axons
8
Q
Retina
A
- located at back of eye, innermost layer of eye
- translates photons in light into an electrical impulse that is transmitted to body via neurons
- “image detector”
9
Q
Optic Nerve
A
sends information from retina to brain
10
Q
Retinal Cells
A
- rods and cones
- light absorbing cells of the retina
- responsible for transduction of photons into an electrical signal
11
Q
Structure of Rods and Cones
A
- contain mitochondria and nucleus
- light absorbing portion (membrane shelves lined with rhodopsin) face back of the eye
- specialized synapse facing front of eye so they can transduce electrical signal to other cell types that carry signal to optic nerve
12
Q
Rods
A
- contain single rhodopsin pigment
- low sensitivity to detail
- permit night vision
- no color perception
- normally turned on but turn off when light hits
- mostly found in periphery
- slow recovery time
13
Q
Cones
A
- contain 3 different types of photopsin pigments
- sensitive to both color and detail
- absorb light in red/green/blue spectrum
- best in bright light
- concentrated at fovea
- fast recovery time
14
Q
Bipolar Cells
A
- first cells that receive light
- direct input from rods/cones
- highlight gradients
- pass signal to ganglion cells
15
Q
Horizontal and Amacrine Cells
A
- two cell types that affect the bipolar cell before they send signal to ganglion cells
- work together to take information from multiple retinal cells to detect edges and contrasts