HN220 Lecture 10: HE220 Lecture 10 - Nervous System Winter 2019
Document Summary
Spinal cord: cylinder of nerve tissue, approx 44cm long x 1-1. 4cm diameter, continuous w/ brain, surrounded by vertebral column, origin of spinal nerves (31 pairs) Dermatome: sensory region of skin, each dermatome is served by a spinal cord. Spinal cord & spinal nerves: gray matter: functional halves, dorsal: sensory functions, ventral: motor functions, spinal nerves are mixed, white matter forms tracts, ascending (to sc or brain, descending (from sc or brain) Involuntary movement reflexes: automatic patterned response to a stimulus, stretch reflex, withdrawal and crossed-extensor reflexes, reflex arc: sensory receptor -> afferent neuron -> integration center -> efferent neuron -> effector organ. Withdrawal reflex: note: red coloured interneurons are inhibitory, neurons 2 & 4, note: green coloured interneurons are excitatory, neurons 1 & 3, crosses-extensor reflex, neurons 3 & 4, opposite leg. Sensory physiology: afferent branch of peripheral nervous system, perception: conscious interpretation of the world based on sensory systems, memory, and other neural processes.
