ANAT 321 Lecture Notes - Lecture 6: Postcentral Gyrus, Somatic Nervous System, Afferent Nerve Fiber

• School: McGill University
• Department: Anatomy & Cell Biology
• Course: ANAT 321
• Professor: David Ragsdale

Document Summary

Transduction: external energy into currency of nervous system (action potentials) Filtering process, extract only a small portion of external world; e. g. visual system only detects small portion of em spectrum, specific somatic sensory receptors that extract specific somatic sensory information and filter out all else. Diff aspects of sensation encoded in separate labeled lines. Separate receptors and neurons for each diff submodality (vibration, warmth, cold, itch, pain, light touch), separate pathway for each. Sensory information moving from periphery to brain goes through hierarchal levels, each transformed in diff way. Primary afferent neurons to brain; sent to thalamus, sent to cerebral cortex. Diff afferents end in diff structures, extract diff types of somatic sensory info (e. g. only high frequency; only constant pressure) Transforming stimulus to action potential occurs at nerve ending. Some sensory neurons end in free endings, no specialized structures: pain and temp. Process diff for diff sensations (e. g. em from eye vs touch on skin)