Vision physiology Flashcards
What retinal layer contains cones and rods
Photoreceptor layer
what is the three main parts of rods and cones
cell body, outer segment, inner segment
what does cell body of neuron contain
nucleus and essential cellular component
what does outer segment of neuron contain
visual pigment molecules (capturing light)
Rod/Cones = elongated outer segments with free-floating disc
membranes, enhancing their ability to detect low light levels.
Rods
Rods/ Cones =shorter outer segments with infolded disc
membranes, optimizing them for detecting color and fine details.
Cones
what is the function of the inner segment in photoreceptors
- Connects to the outer segment via a modified cilium.
- Houses mitochondria and organelles for energy production.
- Site of visual pigment synthesis.
what connects the inner and outer segments of photoreceptors
modified cilium
Synaptic terminal in photoreceptors function?
form synaptic connections with bipolar and horizontal, transmitting visual signals to the retina’s neural network
respond to single proton => highly sensitive to light but unable to detect colors rods/cones
rods
requires hundreds of protons to be activated, function best in bright light and color vision
cones
How does visual pigment renewal occur in rods?
New pigments are inserted into newly formed discs that gradually move outward and are shed and phagocytosed by the pigmented epithelium.
How does visual pigment renewal occur in cones?
Pigments are incorporated within existing membrane folds without regular shedding like in rods.
Where are cGMP-gated Na⁺ channels located in photoreceptors?
In the outer segment of photoreceptors.
What is the function of cGMP-gated Na⁺ channels in photoreceptors?
They allow Na⁺ influx in the dark, maintaining the depolarized state of the photoreceptor.
