PSYC 302 Lecture Notes - Lecture 11: Dorsal Root Ganglion, Posterior Grey Column, Ventral Root Of Spinal Nerve
14 Mar 2019
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Document Summary
The spinal cord is encased in the vertebras and meninges. There are dorsal and ventral roots: dorsal: contains sensory information. Ventral horn is larger because motor neurons are larger. Not a lot of neurons in the dorsal horn because this is where the axons come in. Rexed found this and divided the gray matter in to lamina. If you stain for cell bodies, you find there are many different layers of cell types. I-v is dorsal: vi-ix ventral, zona intermedia around the midline is sometimes called x, also called lissauer"s tract, lamina 1 and 2 (superficial, no entry at laminae 3 and 4, deep dh 5 (and 6???) The stimulus comes in the spinal cord through the dorsal root ganglia and synapse in the dorsal horn in substantia gellatinosa: synapse on second-order neuron or interneuron. Secondary afferent axons cross the midline and synapse in lamina 5. Lamina 5 neurons send the information up to the thalamus (mostly by-passing the brainstem.
