MCB 402Systems and Integrative Physiology• Nien-Pei Tsai, Ph.D.• Erik Nelson, Ph.D.http://www.life.illinois.edu/mcb/402/Neurophysiology• Lecture 1: Introduction, Overview of Nervous System, and Cellular Physiology• Lecture 2: Autonomic nervous system• Lecture 3: Somatosensory system• Lecture 4: Special senses I: Smell, Taste and Hearing • Lecture 5: Special senses II: Vision• Lecture 6: Motor system• Lecture 7: Higher functions of the nervous system• Lecture 8: Development and aging in neurophysiologySensory Modalities• General senses:  Somatic senses (from the body)touch, pressure, vibration, itch, warm/cold, etc., Visceral senses (from the organs)pressure, pain, stretch, hunger, warm/cold, etc., Special senses: Smell, taste, vision, hearing.VisionCopyright © 2014 John Wiley & Sons, Inc.Vision – Optic PathwayCopyright © 2014 John Wiley & Sons, Inc.• The retina contains sensors (photoreceptors; receptor cells) known as rods and cones. Vision -- PhotoreceptorsCopyright © 2014 John Wiley & Sons, Inc.Vision -- Photoreceptors• The retina contains sensors (photoreceptors) known as rods and cones. Constazo, Physiology 5th• Rods contain only rhodopsin.• Three types of cones contain three different photopigments, one for each of the three types of cones (red, green, blue). Vision -- Photopigmentshttp://oerpub.github.io/epubjs-demo-book/content/m46577.xhtmlVision -- Photopigments• All types of photopigments contain two parts:1. opsin: a glycoprotein2. retinal: a derivative of vitamin Ahttp://starklab.slu.edu/Physio/Membranes.htmTrends in Molecular Medicine, 2010 Oct;16(10):435-46Vision – Photoreceptioncis-retinaltrans-retinalisomerizationVision – PhotoreceptionGlutamate is an inhibitory neurotransmitter in optic pathway.Vision – PhotoreceptionCopyright © 2014 John Wiley & Sons, Inc.Photopigment regenerationVision – Optic PathwayCopyright © 2014 John Wiley & Sons, Inc.http://physrev.physiology.org/content/85/3/845Vision – Pigment EpitheliumVision – Optic pathway• The anterior location of our eyes leads to visual field overlap. This gives us binocular vision.Copyright © 2014 John Wiley & Sons, Inc.• Images focused on the retina are inverted and right-to-left reversed due to refraction. The brain corrects the image.VisionCopyright © 2014 John Wiley & Sons, Inc.Vision• Light refracts (bends) when it passes through a transparent substance with one density into a second transparent substance with a different density. This bending occurs at the junction of the two substances.Copyright © 2014 John Wiley & Sons, Inc.Vision – Abnormal RefractionSummary• Retina: the main area in the eyes that converts light into nerve impulses.• Photoreceptors: Rods and Cones• Photopigments: Opsin and Retinal• Photoreception: Conversion of Retinal; cGMP signaling; Photopigment regeneration• Pigmented layer (Pigment Epithelium)• Optic pathway: Signal transmission inside the retina;Nerve pulses from retina to visual cortex • Abnormal