Lecture 25

Question 1

retina

Answer 1

rod cell杆状细胞, cone cell锥状细胞, horizontal cell水平细胞, bipolar cell双极细胞, amacrine cell无长突细胞, ganglion cell神经节细胞

Question 1

phototransduction

Answer 1

photon capture by disc, chromophore and opsin separate, conformation change in opsin molecule, photon has a lot of energy, G protein cascade, cGMP convert to GMP, cGMP Na channel closed, transduction

horizontal cell & amacrine cell & bipolar cell convert reduction in neuron transmitter to increase drive of ganglion cell

Question 2

difference btw rod and cone cell

Answer 2

rod
high sensitivity, night vision
more rhodopsin, capture more light
high amplification
slow response
more sensitivity to scattered light
low acuity
1 type of opsin

cone
low sensitivity, day vision
less opsin
low amplification
fast response
more sensitivity to direct axial ray
high acuity
3 types of opsin

Question 2

dark and light adaptation

Answer 2

dark adaptation
bright light to dark environment
temporary blindness until rod reactivate and take over

light adaptation
rod initially saturate
temporary blindness until rod inactivate and cone take over