Rod and Cone Cells

le function of rod and cone cells in the e

. We c an s e e t h in gs b ec a us e o u r e y e h a s a l i g h t - sensitive layer called retina. . A t t h e s u r f a c e o f t h e r e t i n a , t he re a re m il li on s o f lightsensitive cells called receptors.

Receptors

.There are two types of receptors that are s e n s i t i v e to light, namely rod cells and cone cells . in the ey e Rod cells r ar e on l y s en si ti ve t o i ) Ro d c el el ls ls ar e no t shades sensitive to colours. of grey and give us > )R )R o d c el e l ls ls ar e  blac! and white sensitive to low vision vision.. ) Rod cells cells intensity of light. light. function function well in dim ) n o t h e r   light. w or ds , t he y

Rod cells

Figure 7.49 Rod cells and cone cells

)This e"plains why ob#ects appear in s h a d e s o f grey at night. Cone cells ‘

(a) $one cells are sensitive to coloured lights. (b) %owever, cone cells can only function well in fairly bright conditions, which

means we are not able to see coloured ob#ects in dim light. (c) There are three types of cone cells& one type is sensitive to red light, another to blue light, and the third to green light. (d) $one cells are more suitable for seeing in daylight.