Spinal-cord back horn {dorsal horn} is for sense input and has ascending sense-connector nerves.
functions
Dorsal column is for fine touch and proprioception from skin, tendon, and joint.
layers
Dorsal horn has five layers. Layer 1 receives axons from skin neurons and sends to neurons higher in spinal cord. Layers 2 and 3 modulate sense input from both skin neurons and neurons in layers 4 and 5. Layer 4 receives axons from skin neurons and sends axons to layer 5. It detects gentle and general pressures. Layer 5 receives axons from skin, viscera, and layer-4 neurons and sends to brain.
nuclei
Neuron nuclei {dorsal column nuclei} receive afferent fibers from skin and send to ventrobasal complex.
tracts
Tracts are spinothalamic tract, dorsal spinocerebellar tract, ventral spinocerebellar tract, and spinoreticular pathway.
neurons
Nociceptive-specific neurons respond to noxious stimuli. Wide dynamic range neurons respond to all mechanical stimuli, but especially to noxious mechanical or thermal stimuli.
Spinal-cord front horn {ventral horn} is for motor output and has descending motor nerves. Tracts are lateral corticospinal tract, anterior corticospinal tract, vestibulospinal tract, rubrospinal tract, reticulospinal tract, and tectospinal tract. Descending autonomic neurons come from hypothalamus and brainstem. Medial longitudinal fasciculus is for head and eye coordination and comes from vestibular nuclei.
Voluntary escape behaviors use small efferent spinal cord fibers with long latencies and variable responses, which react to visual, tactile, and vibratory threats.
4-Zoology-Organ-Nerve-Spinal Cord
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0225