1. Bio 449Lecture 12 - Sensory Physiology IVSep. 22, 2010 Vision - the eye Gross structure and function Focusing mechanism Photoreceptors Structure Transduction of light Integration of receptor signals Terms to Know Rod Cone Inner segment Outer segment Lamellae Rhodopsin Retinal Opsin Transducin Phosphodiesterase (PDE) Guanosine monophosphate (GMP) Bipolar cells Horizontal cells Ganglion cells Readings Lectures 10-12:Chapter 10, pages 349-379 Lectures 13-14:Chapters 6 & 7 Terms to Know Cornea Sclera Lens Iris Ciliary muscles Zonular fibers Retina Fovea Optic nerve

2. Anatomy of the Eye Fig. 10-30 Vitreous chamber Aqueous humor Cornea Fovea Optic nerve Iris Pupil Retina Sclera is connective tissue. Ciliary muscle Central retinal artery and vein Canal of Schlemm Optic disk (blind spot) Lens Zonular fibers

3. Anatomy of the Eye Rod (monochromatic vision) Cone (color vision) Bipolar cell Ganglion cell Amacrine cell Horizontal cell Neurons where signals from rods and cones are integrated Light Fig. 10-37

4. Anatomy of the Eye Ganglion cell Fovea Cone Rod Bipolar neuron Light Pigment epithelium of retina absorbs excess light. Fig. 10-37

5. Focusing Mechanism Fig. 10-37 Fovea RetinaOptic nerve Macula Lens Light Fixation point

6. Focusing Mechanism Fig. 10-34 Cornea Iris Lens Ligaments Ciliary muscle

7. Focusing Mechanism Fig. 10-34 Cornea Ligaments pulled tight Lens flattened Ciliary muscle relaxed Ligaments slacken Lens rounded Ciliary muscle contracted

8. Photoreceptor Structure Fig. 10-39 OUTER SEGMENT INNER SEGMENT SYNAPTIC TERMINAL Bipolar cell Disks Connecting stalks Mitochondria Cone Rods LIGHT Retinal Rhodopsin molecule Disks Opsin

9. Photoreceptor Sensitivity Fig. 10-39

10. Integration of Signals Fig. 10-37 To optic nerve Pigment epithelium Rod Bipolar cell Ganglion cell