What are the two major classifications of nerves that we study in the body
Spinal nerves and cranial nerves
What does a “nerve fiber” refer to?
The axon of a neuron
How are spinal nerves named?
They are named by the vertebrae from which they emerge (ex. Thoracic 3, remember that these are pairs)
What does it mean that spinal nerves are mixed nerves?
Each nerve contains Sensory and Motor axons, so it has signals within it that go to and from the spinal cord
Ventral Root: Located on ventral (anterior) side of the body. Contains motor fibers that extend to skeletal muscles.
Dorsal Root: Located on dorsal (posterior) side of the body. Contains sensory fibers that conduct signals from receptors to the spinal cord
Dorsal Root Ganglion: Residence of sensory neuron cell bodies
What classifies a neuron as unipolar? What neurons in spinal nerves are classified as this?
Only one protrusion from the cell body. This is the case with sensory neurons, and the reason why they form a ganglion.
What is a ganglion?
A bundle of neuron cell bodies outside the CNS
Anterior Ramus: Innervates; anterior and lateral skin and muscles of the trunk, Also the upper and lower limbs, in thoracic region forms an intercostal nerve that innervates the skin and intercostal muscles.
Posterior Ramus: innervates; muscles and joints in that region of the spine and the skin of the back.
Meningeal branch: Reenters the vertebral canal and innervates the meninges, vertebrae, and spinal ligaments.