Where is the spinal nerve and what is it made of?
http://en.wikipedia.org/wiki/Spinal_nerve
The spinal nerves are a part of the peripheral nervous system and are located in the vertebral column or backbone. They arise from the spinal cord, which runs through the spinal canal formed by the vertebral column.
To understand what the spinal nerve is made of, it is important to know the components of a typical spinal nerve. Each spinal nerve consists of two main types of fibers: sensory fibers (afferent fibers) and motor fibers (efferent fibers).
1. Sensory fibers: These are responsible for transmitting sensory information from the body's periphery (such as skin, muscles, organs) to the central nervous system. They carry information about pain, touch, temperature, pressure, and proprioception (position sense).
2. Motor fibers: These fibers carry commands from the central nervous system to the body's muscles and glands. They are involved in initiating and controlling voluntary movements, glandular secretion, and other motor functions.
In addition to these fibers, spinal nerves contain other structures such as blood vessels and connective tissue that provide support and nourishment.
It is worth noting that there are 31 pairs of spinal nerves in humans, with each pair exiting the spinal cord through small openings between adjacent vertebrae known as the intervertebral foramina. These individual spinal nerves then branch out and extend to various regions of the body, forming extensive networks to facilitate communication between the body and the central nervous system.