Grade 12: Sense Organs
, Receptors
• Receptors detect a variety of
different stimuli such as light, sound,
touch, temperature, pressure, pain
and chemicals (taste and smell).
, Receptor Types
Chemoreceptors
• respond to changes in chemical concentrations
Pain receptors
• respond to tissue damage
Thermoreceptors
• respond to changes in temperature
Mechanoreceptors
• respond to mechanical forces
Photoreceptors
• respond to light
, Photoreceptors
• Rods for vision in dim light (120 million)
– Found more towards periphery
• Cones for color vision and visual
acuity (6 million)
– Only work in bright light
– Three types: red, green, and blue
• Overlap of three ranges gives us all the
colors
– Color blindness is sex-linked (males)
, Receptors
• Receptors detect a variety of
different stimuli such as light, sound,
touch, temperature, pressure, pain
and chemicals (taste and smell).
, Receptor Types
Chemoreceptors
• respond to changes in chemical concentrations
Pain receptors
• respond to tissue damage
Thermoreceptors
• respond to changes in temperature
Mechanoreceptors
• respond to mechanical forces
Photoreceptors
• respond to light
, Photoreceptors
• Rods for vision in dim light (120 million)
– Found more towards periphery
• Cones for color vision and visual
acuity (6 million)
– Only work in bright light
– Three types: red, green, and blue
• Overlap of three ranges gives us all the
colors
– Color blindness is sex-linked (males)
