Human nervous system:
A) Central nervous system (CNS)– consists of the brain and the spinal cord
B) Peripheral nervous system (PNS) – composed of nerves which connect the CNS to the other parts of the body.
- Somatic system (skeletal) – nerves (motor and sensory) that control the muscular system and the external sensory receptors
- Autonomic system - autonomic motor neurons that control the internal organs (such as heart, arteries, gastrointestinal tract, glands..)
- Sympathetic system - responds to stressful stimulation – prepares the body for fight or flight response
- Parasympathetic system – involved in relaxation and has an energy conserving function