Special Senses Physiology

Question 1

Rods

Answer 1

• Convergence: many rods and many bipolars –> one ganglion cell
• Allows the rod system to operate in dim light
• Sacrifices acuity to gain sensitivity
• Peak density at an eccentricity of about 20 degrees

Question 2

Cones

Answer 2

• Less convergence – receptor may send information to one bipolar cell that contacts one ganglion cell
• Maximizes acuity
• Peak density at center of fovea (0)
• Used to see color

Question 3

Pathway of Photoreceptors in Conditions of Darkness

Answer 3

(1) Photoreceptor depolarizes
(2) Graded potential is generated
(3) Glutamate is released from photoreceptor
(4) Glutamate acts as inhibitory signal on the Bipolar Cell (mGluR6)
(5) Bipolar cell does not depolarize – no release of Glutamate
(6) Ganglion cell does not depolarize
(6) No impulse sent to brain so do not see anything

Question 4

Pathway of Photoreceptors in Conditions of Light

Answer 4

(1)