THE PERIPHERAL NERVOUS SYSTEM
The peripheral nervous system (PNS) is the system of nerves outside of the central nervous system (CNS or brain and spinal cord).
The central nervous system (CNS) is responsible for all involuntary nerve action, meaning you DO NOT have to initiate it or think about it in order for it to work.
The peripheral nervous system (PNS) runs from your spinal cord to your appendages (arms, legs, hands and feet) and you DO HAVE TO consciously and voluntarily make this nervous system move or work.
"Included" in the peripheral nervous system (PNS) are the 12 pairs of cranial nerves, 31 pairs of spinal nerves and their branches to the entire body. Also included in this system are all sensory nerves and the sympathetic and parasympathetic nerves. The parasympathetic and sympathetic nervous system are part of the autonomic nervous system (ANS).
The autonomic nervous system (ANS) is concerned with control of involuntary bodily functions. You do not have to think about it to make them work. Meaning, the nerves originate in the spinal cord (CNS) and go directly to areas in the trunk and that are NOT appendages. These nerves stay within the trunk and effect organs and tissues that automatically work. It regulates the funtion of glands; salivary, gastric, sweat and adrenal glands; smooth muscle tissue that makes up organs and the heart.
Fright or Flight response in the sympathetic nervous system gives vasoconstriction of the part that is supplied, rise in blood pressure, erection of hairs, gooseflesh, pupillary dilation, secretion of small quantities of thick saliva, depression of gastrointestinal activity and acceleration of the heart. These activities occur in emergencies such as fright and are associated with the expenditure of energy as a response to the need to flee, fight or be frightened. You can call this "intuition" or "gut feeling." Your body knows!
Wine and dine response in the parasympathetic nervous system generally produces vasodilation of the part supplied, general fall in the blood pressure, contraction of the upil, copious secretion of thin saliva, increased gastrointestinal activity, and slowing of the heart. The parasympathetic nervous calms the body, therefore it is referred to as the "wine and dine" nervous system.
The central nervous system, gives rise to the peripheral nervous system (the nerves on the periphery of the body). The the autonomic nervous system (ANS) is under control of central nervous system and is also part of the peripheral nervous system, although these nerves stay within the body and effect organs and soft tissues and do not leave to effect appendages (arms and legs). The autonomic nervous system (ANS) is "automatic" and in control of involuntary bodily functions and it is divided into two parts: The sympathetic and parasympathetic nervous system. It regulates the function of glands, the adrenal medulla, smooth muscle tissue, organs and the heart.
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