eye and retina 2 Flashcards
How to connections vary between rod and cone cells?
Cones have direct root to ganglin cells, and 1 cone cell is connected t 1 bipolar cell.
There are multiple rods connected to 1 bipolar cell
Compare the properties of rods and cones
Rods have high sensitivity, high convergance, but low resolution and low visual acuity.
Cones hve low sensitivity and low convergance, but high resolution and visual acuity.
What type of vision are rods and cones responsible for?
rods - peripheral vision
cones- central (foveal) vision
What are the 1st and 2nd order neurons in eye?
1st = bipolar cells
2nd-ganglion cells
What are the 2 cells that contrast intensity?
horizontal and amacrine cells
What is the duplicity theory?
can’t have high sensitivity and high resolution in single receptor –
thus separate systems for colour and monochrome
How are rods connected to ganglion cells?
they are connected via amacrine cells
What are the pigments for rod and cone cells?
rod- rodopsin
cone - photopsin
What are the colours cone cells can see?
Red 558nm
Green 531nm
Blue 420nm
What happens to sodium channels when lights hits rod cells?
rod cells actice - sodium channels close - calcium decreases in cytosol.
what does transduction involve?
enzyme cascade that causes signal amplification
What role does glutamate play in ON bipolar cells?
ON
Glutamate inhibits (hyperpolarizes)
ON bipolar cells via metabotropic
glutamate receptors.
What synaptic potential is created in light and dark?
In light - EPSP excitatory post synaptic potential
In dark - IPSP Inhibitory post synaptic potential
What happens to glutamate in dark and light?
In light glutamate release ceases (is inhibited), in dark glutamate is released.
Do photoreceptors only release glutamate?
YES
