BIO271H1 Lecture Notes - Lecture 5: Tetrachromacy, Thalamus, Depth Perception
Document Summary
Lecture 5: sensory physiology photoreceptor. Photoreception and the electromagnetic spectrum. Ability to detect visible light. 300nm- 350nm of the electromagnetic spectrum. A small proportion of the electromagnetic spectrum from ultraviolet to near infrared. Ability to detect this range of wavelengths supports idea that animals evolved in water. Visible light travels well in water; other wavelengths do not. Evolution of photoreceptors receptors that absorb photons of light and transmit it into an electrical signal. Humans in these: rhabdomeric photoreceptors (blue): apical surface covered with multiple outfoldings called microvillar projections; microvillar projections contain photopigments. Photopigments: molecules that absorb energy from photons. Both photoreceptor cells have photopigments differ in where the photopigment is located. Vertebrates have ciliary photoreceptors. Both have the same general shape. At the back of the retina (located at the back of the eye) These photoreceptors are at the back of the eye. Difference: the properties of the photopigments. Both have inner and outer segments. Outer segment contains photopigments.
