biosci35-finalsg

biosci35-finalsg - Bio Sci 35 Final Study Guide I....

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Bio Sci 35 – Final Study Guide I. Somatosensory System A. General Information 1. Mechanical and Chemical receptors (modified neurons) translate stimuli into electrochemical reactions. 2. Information Processing – path of processing until perception by brain. a) Serial Processing – series of chemical of reactions, from station to station until perception. b) Parallel processing – multiple reactions down multiple processing at the same time. B. Somatosensory Perception 1. Hapsis – fine touch and pressure 2. Proprioception – body sense, location/movement of body including muscles, joints, and tendons. 3. Nociception – pain and temperature C. Somatosensory Pathways 1. Dorsal-Column Medial-Lemniscus – hapsis and proprioception information a) Pathway: i) Enters dorsally ii) Ascends dorsally iii) Synapses contralaterally through the dorsal column nuclei in the medial lemniscus in the medulla iv) Information is sent to the thalamus v) Relayed to the primary somatosensory cortex. b) Axons are big and myelinated. 2. Anterolateral – Nociception information a) Pathway: i) Enters dorsally ii) Synapses contralaterally in the spinal cord (SC). iii) Ascends to medial lemniscus. iv) Sent to thalamus v) Relayed to primary somatosensory cotex. b) Axons are small and unmyelinated. D. Pain 1. Modulation at SC a) Hapsis info inhibits nociceptive info on the anterolateral path by releasing enkephalin in an axo-axonic synapse. 2. Descending Pathway : Peri-Acqueductal Grey Area (PAG), Raphé, SC a) PAG: Inhibitory Interneuron (has opiate receptors that inhibit this neuron when active) that is tonically (constantly) active. b)
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This note was uploaded on 04/16/2008 for the course BIO SCI 35 taught by Professor Dickinson-anso during the Fall '07 term at UC Irvine.

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biosci35-finalsg - Bio Sci 35 Final Study Guide I....

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