Spinal Nerves Flashcards
CNS
brain and spinal cord
PNS
cranial, spinal, and ganlia
ganglion
collection of neuron cell bodies outside CNS
Sensory innervation
brings info from environment to CNS f
Motor innervation
sends instructions from CNS to muscles and glands
Motor neuron
found in CNS, no axon divided, cell body at the end
electrical impulse direction of motor neuron
flows 1 direction to skeletal muscle
electrical impulse direction of sensory neuron
flows 1 direction to CNS
Sensory neuron structure
found in PNS, axon divided, cell body in the middle
somatic
innervation with body wall
viseral
innervation with internal organs
Paraxial mesoderm
on either side of neural tube
Dermomyotome
provides cells for dermis and striated muscle, where all structures are derived from
Dermatome
region of skin innervated by branches of single spinal nerve
Epaxial dermamyotomes
give rise to intrinsic (deep) back muscles and dermis that covers them; supplied by dorsi rami
Hypaxial dermamyotomes
give rise to all other skeletal muscle and dermis below neck and limbs (extrinc); supplied ventral rami
Sensory neurons location
dorsal horn of spinal gray matter
Motor neuron location
ventral horn of spinal gray matter
Ventral root
fusion of motor axons into a single bundle; will divide into dorsal ramus and ventral ramus
Dorsal Root
Central process from ganglion that goes TOWARDS spinal cord
Dorsal ramus
epaxial muscles
ventral ramus
hypaxial muscles
Paravertebral ganglia
- Ganglia lie lateral to developing vertebral bodies
- Send their axons into ventral ramus of nearby spinal nerve
Gray ramus communicans
carries postganglionic axons to ventral ramus
Preganglionic sympathetic axons
- all ventral roots T1-L2
- all spinal nerves and ventral rami from T1- L2
White ramus communicans
white nerve bundle that communicates LATERAL. Only located between T1-L2. It can travel to other locations through sympathetic trunk
Postganglionic neuron
cell body outside CNS, parasympathetic
