31 Pairs of the Spinal Nerve
- There are 31 pairs of spinal nerves.
- Mixed nerve fibers are formed by the joining of the anterior motor and posterior sensory roots.
- Posterior roots contain afferent (sensory) nerve fibers.
- Anterior roots contain efferent (motor) nerve fibers.
Autonomic nervous system
- Sympathetic (adrenergic) fibers dilate pupils, increase heart rate and rhythm, contract blood vessels, and relax smooth muscles of the bronchi.
- Parasympathetic (cholinergic) fibers produce the opposite effect.
- Amino acids
- The neuron consists of the cell body, axons, and dendrites.
- The cell body contains the nucleus.
- Neurons carrying impulses to the central nervous system (CNS) are called sensory neurons.
- Neurons carrying impulses away from the CNS are called motor neurons.
- Synapse is the chemical transmission of impulses from one neuron to another.