Week 3: Spinal Cord Anatomy Flashcards
what is a spinal nerve ?
the spinal nerve breaks off into two branches: anterior/ventral root and posterior/dorsal root. it is a mixed nerve because it has both sensory and motor components.
what is a nerve ?
bundles of axons.
what is the dorsal root ganglion ?
the bulge on the posterior root where neuron cell bodies are located.
sensory axons travel through which side ?
posterior root.
the sensory neuron will then synpase with?
an intermediate neuron called the interneuron.
the interneuron synapses with ?
somatic motor neuron which leaves through the anterior root of the spinal nerve.
what about the cell body of the autonomic motor neuron ?
goes through the anterior root but doesn’t synapse with anything.
what is the posterior median sulcus ?
the posterior median sulcus is a shallow groove that runs along the midline of the spinal cord dividing it into two halves.
what is the anterior median fissure ?
a deep groove on the anterior side of the spinal cord dividing it into two halves.
what is gray matter ?
gray matter consists of neuron cell bodies, dendrites, unmyelinated axons, and glial cells.
what is white matter ?
myelinated axons.
what is the gray commissure ?
thin band of gray matter that connects the right and left sides of the spinal cord.
what is the central canal ?
small hole in the center of the spinal cord that contains csf.
what is the posterior gray horn ?
part of the gray matter on the posterior side of the spinal cord.
what is the anterior gray horn ?
part of the gray matter on the anterior side of the spinal cord.
lateral gray horn ?
the gray matter bulges in between the posterior and anterior sides of the spinal cord. only present in the thoracolumbar regions of the spinal cord.
what is the anterior white commissure ?
connecting both the right and left sides of the spinal cord.
anterior white column ?
white matter located on the anterior side of the spinal cord.
posterior white column ?
white matter located on the posterior side of the spinal cord.
lateral white column ?
white matter on the sides in between the posterior and anterior sides of the spinal cord.
each column of white matter contains axons that have a common ?
origin or destination. they either contain sensory tracts or motor tracts.
sensory vs motor tracts ?
sensory tracts: these are up pathways. they carry sensory information like touch, pain, or temperature up tot he brain.
motor tracts: these are the down pathways, they carry commands from the brain down to the muscles to make them move.
similarity: both sensory and motor tracts are made up of myelinated axons that travel in the white matter of the spinal cord.
what is a tract ?
bundle of myelinated axons.
gracile fasciculus and cuneate fasciculus ?
located in the posterior column of the spinal cord that carry touch, pressure, and proprioception information from the body to the brain.
gracile fasciculus: carries sensory information from the lower body (legs and lower trunk).
cuneate fasciculus: carries sensory information from the upper body (arms, neck, and upper trunk).
what is the lateral corticospinal tract ?
where most of the voluntary movement information will be carried from the tracts.
what is proprioception ?
proprioception is the body’s ability to sense its position and movement without the need for visual input.
what is reflex arc ?
stimulus: something happens like touching a hot stove. this activates sensory receptor in the skin. triggers an action potential within the dendrite of a sensory neuron which will travel along axon goes through posterior root ganglion and axon enters into the posterior gray horn of the spinal cord. sensory neuron synapses with interneuron whos axon then projects to the anterior gray horn which synapses with motor neuron and the axon projects out of the anterior root of the spinal nerve and travel through the body and act on effector such as muscle or gland that responds to the stimulus.
