Peripheral Nervous System PNS has two important parts. Skeletal/Somatic Nervous System. Autonomic Nervous System (ANS) Peripheral Nervous System (PNS) consists of the spinal and cranial nerves these connect the CNS to the rest of the body. PNS connects the body’s sensory receptors to the CNS, and the CNS to the muscles and glands.
1 Skeletal/Somatic Nervous System
• Controls the voluntary movements of our skeletal muscles.
• It reports the current state of skeletal muscles and carries instructions back.
2 Autonomic Nervous System (ANS)
• Considered as the “self governing or self-regulatory mechanism” because of its involuntary operation.
• Controls the glands and muscles of internal organs e.g. heart, stomach, and glandular activity.
• A.N.S. has a dual function; i.e. both arousing and calming.
• Comprises two sub systems; Sympathetic and parasympathetic nervous systems.
A. Sympathetic Nervous System (SNS)
• This part of ANS arouses us for defensive action…. fight or flight.
• If something alarms, endangers, excites, or enrages a person, the sympathetic nervous system accelerates heart beat, slows digestion, raises the sugar level in blood, dilates the arteries and cools the body through perspiration; makes one alert and ready for action.
B. Parasympathetic Nervous System (PNS)
When the stressful situation subsides, parasympathetic nervous system begins its activity.
• It produces an effect opposite to that of sympathetic nervous system.
• It conserves energy by decreasing heart beat, lowering blood pressure, lowering blood sugar and so on. In daily life situations, both sympathetic and parasympathetic systems work together to keep us in steady internal state maintaining the homeostasis.