Question

Which of the following is the correct difference between rod cells and cone cells of our retina?

• A. Distribution
  Rod cells: More Evenly concentrated all over in centre of retina.
  Cone cells: Distributed all over the retina
• B. Visual activity
  Rod cells: High
  Cone cells: Low
• C. Visual pigment
  Rod cells: Iodopsin
  Cone cells: Rhodopsin
  
• D. Major function
  Rod cells: Aids vision poor light
  Cone cells: Aids in colour vision and detailed vision in bright light

Answer 1

The correct option is D Major function

Rod cells: Aids vision poor light
Cone cells: Aids in colour vision and detailed vision in bright light
Various differences between rods and cones:

Point of difference	Rods	Cones
Number	More numerous, about 125 millions in each eye	Less than rods, about 2 millions in each eye
Pigment activity	Rhodopsin is sensitive to light	Iodopsin is less sensitive to light
Vision	Dim light (night vision)	Bright light
Visual pigment	Only 1, black and white	3 pigments to differentiate colours
Location	Periphery of retina	Centre of retina
Response time towards light	Slow response, long integration time	Fast response, short integration time
Shape of outer segment	Cylindrical	Conical
Size	Small	Large
Light level	Scotopic	Photopic
Absolute sensitivity	High	Low
Visual acuity	Poor, many rods share common neuron connection to brain	Good, each cone cell has its own neural connection to brain