What kind of fibers are found in spinal nerves?

Sensory fibers:

- Somatic afferent fibers: Transmit sensory information from the skin, muscles, joints, and tendons to the central nervous system. These include:

- Mechanoreceptors: Respond to touch, pressure, and vibration.

- Thermoreceptors: Respond to changes in temperature.

- Nociceptors: Respond to painful stimuli.

- Visceral afferent fibers: Transmit sensory information from the internal organs to the central nervous system.

Motor fibers:

- Somatic efferent fibers: Transmit motor commands from the central nervous system to the skeletal muscles. These include:

- Alpha motor neurons: Innervate extrafusal muscle fibers, which are responsible for generating muscle contraction.

- Gamma motor neurons: Innervate intrafusal muscle fibers, which are responsible for regulating muscle tone.

- Visceral efferent fibers: Transmit motor commands from the central nervous system to the smooth muscles, cardiac muscle, and glands.