Nervous System 101
The nervous system is divided into two parts:
brain and spinal cord
cranial and spinal nerves.
Sensory (afferent) Neurons
transmits impulses TO the CNS
Motor (efferent) Neuron System -
transmits impulses FROM the CNS to effectors.
Somatic Nervous System – directs contraction of skeletal muscles
Autonomic Nervous System – controls activities of organs and various involuntary muscles, such as
cardiac and smooth muscles. Has 2 systems that generally target the
same organs but are antagonistic.
Parasympathetic Nervous System “Rest and Digest” or “Brake” – activates tranquil functions. E.g. secretion
of saliva or digestive enzymes.
Sympathetic Nervous System “Fight or Flight” or “Accelerator”
prepare body for action. E.g. increasing heart rate, increasing sugar release
from liver to blood.