Chapter 12 Somatic sensory system

Chapter 12 Somatic sensory system - Chapter 12 The Somatic...

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Sheet1 Page 1 Chapter 12 The Somatic Sensory System T regular class room (PH 111) multiple choice questions, valid excuse to take the make-up exam: questions (not multiple choice) excuse to take the make-up exam, you will receive azero on the exam. This will count toward your finalgrade in the class, no e x e Somatosensory receptors S Small vs. large receptive fields h h palm p Mechanoreceptors vary in their response to long-lasting stimuli They respond only to onset and offset of stimulus. These receptors provide information about dynamic qualities of the stimulus h Practice Exam will be on Sakai soon The exam is March 13th, during regularclass period (10:20 h 11:40), in the h Exam will have same format as the first exam h If you can not make it to the exam, you will need a Doctorhs note or Deanhs letter h Make-up exam will be short answer / short essay style h If you missed the exam and do not have a valid Meissnerhs corpuscles and Merkelhs disks have small receptive fields h a few millimeters wide Pacinian corpuscles and Ruffinihs corpuscles have large receptive fields h covering an entire finger or half the Meissnerhs corpuscles Pacinian corpuscles and Merkelhs disks and Ruffinihs endings Meissnerhs corpuscles and Pacinian corpuscles are rapidly adapting.
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Page 2 they generate a more sustained response during a long stimulus and provide information about static qualities of the stimulus p Pacinian corpuscles are made up of layers of connective tissue, with an unmyelinated axon in the center h Stimuli applied to the skin compresses the capsule and energy istransferred to the axon h stretching or changes in tension in the axonal cell membrane result in the opening of mechanosensitive ion channels h Ions flowing through these receptors depolarize the axon, resulting in a receptor potential h If the receptor potential is large enough it will trigger an action potential h It is the layered capsule that give the receptor its specific properties p Primary afferent axons bring information from the somatic sensory receptors to the CNS h The diameter of the axon correlates with its action potential conduction speed h Different diameter axons are connected to the different types of sensory receptors s Touch sensations are sent into the spinal cord by A axons h One branch of the axon ascends to the brain in the dorsal column h The other branch synapse on second order neurons in the dorsal horn h Sensitivity of tactile discrimination varies across the body surface
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This note was uploaded on 04/03/2008 for the course NEUROBIOLO Fund Neuro taught by Professor Schjott during the Spring '08 term at Rutgers.

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Chapter 12 Somatic sensory system - Chapter 12 The Somatic...

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