State the difference between the rod and cones
Answers
• Rods are rod-shaped, and cones are cone-shaped.
• Rods contain more photopigments, whereas cones contain less.
• Response of rods is slow, whereas that of cones is fast.
• Rods take long integration time while cones take short integration time.
• Cones have less amplification, whereas rods have high amplification due to the single quantum detection in rods.
• Unlike the cones (except S-cones), rods’ response saturates when a small amount of a pigment is bleached.
• Rods are not directionally selective, unlike the cones.
• Cones have lower absolute sensitivity while rods have high sensitivity due to the greater number of disks and higher pigment concentration.
• Degree of spatial integration results low acuity in Rods while, high acuity in cones.
• Rods are achromatic while cones are Chromatic. Hence, cones are important in color vision.
• The scotopic retina uses rods while the photopic retina uses cones.
Answer:
Cone cells :-
° iodopsin is the pigment
° helps in distinguishing colours
° Photopic vision (bright vission)
Rod cells :-
° Rhodopsin is the pigment
° Helps in distinguishing colourless objects.
° scotopic vision (dim light)