Sensory System - Vision Flashcards
1
Q
Rods characteristics
A
- cylindrical
- sensitive under low light
2
Q
Cone characteristics
A
- sensitive to colour
- need high energy to activate
3
Q
What is the resting membrane potential of photoreceptors?
A
-35mV
4
Q
What happens in dark environments?
A
Depolarisation
5
Q
What happens in light environments?
A
Hyperpolarisation
6
Q
What is the transduction mechanism for sight?
A
- Light absorbed by rhodopsin
- Activates G protein transducin
- Activates enzyme phosphodiesterase
- Phodphodiesterase deactivates cGMP into 5’cGMP which closes Na+ channels
- Closure of Na+ channels leads to hyperpolarisation
7
Q
What forms a connection between receptors and the optic nerve?
A
Bipolar cells
8
Q
Do bipolar cells produce action potentials?
A
No
9
Q
What pumps/channels are present in rods/cones?
A
- specialises sodium pump
- K+ channels
- K+/Na+ ATPase pump
