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*AUTONOMIC NERVOUS SYSTEM*
*PARA-SYMPATHETIC NERVOUS SYSTEM*
*SYMPATHETIC NERVOUS SYSTEM*
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(the peripheral nervous system (PNS) is the part of the ‘nervous system’ that consists of the ‘nerves’ and ‘ganglia’ outside of the ‘brain’ + ‘spinal cord’)
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(the main function of the PNS is to connect the ‘central nervous system’ (CNS) to the limbs and organs, essentially serving as a communication relay going back and forth between the brain and spinal cord with the rest of the body)
(unlike the ‘CNS’, the ‘PNS’ is not protected by the bone of spine and skull, or by the “blood–brain barrier”, which leaves it exposed to ‘toxins’ and ‘mechanical injuries’)
The peripheral nervous system is mainly divided into the somatic nervous system and the autonomic nervous system.
In the somatic nervous system, the cranial nerves are part of the PNS with the exception of cranial nerve II, the optic nerve, along with the retina.
The second cranial nerve is not a true peripheral nerve but a tract of the diencephalon.
Cranial nerve ganglia originate in the CNS.
However, the remaining ten cranial nerve axons extend beyond the brain and are therefore considered part of the PNS.
The Autonomic nervous system is an involuntary control of smooth muscle.
(the connection between CNS and organs allows the system to be in two different functional states: ‘sympathetic’ and ‘parasympathetic’)
The PNS consists mainly of nerves, which are enclosed bundles of the long fibers or axons, that connect the CNS to every other part of the body. Nerves that transmit signals from the brain are calledmotor or efferent nerves, while those nerves that transmit information from the body to the CNS are called sensory or afferent. Most nerves serve both functions and are called mixed nerves. The PNS is divided into a) somatic and b) autonomic nervous system, and c) the enteric nervous system. Somatic nerves mediate voluntary movement. The autonomic nervous system is further subdivided into the sympathetic and the parasympathetic nervous systems. The sympathetic nervous system is activated in cases of emergencies to mobilize energy, while the parasympathetic nervous system is activated when organisms are in a relaxed state.
(the ‘enteric nervous system’ functions to control the ‘gastrointestinal system’)
(both autonomic and enteric nervous systems function involuntarily)
(nerves that exit from the ‘cranium’ are called ‘cranial nerves’ while those exiting from the ‘spinal cord’ are called ‘spinal nerves’)
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👈👈👈☜*“THE NERVOUS SYSTEM”* ☞ 👉👉👉
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💕💝💖💓🖤💙🖤💙🖤💙🖤❤️💚💛🧡❣️💞💔💘❣️🧡💛💚❤️🖤💜🖤💙🖤💙🖤💗💖💝💘
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*🌈✨ *TABLE OF CONTENTS* ✨🌷*
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🔥🔥🔥🔥🔥🔥*we won the war* 🔥🔥🔥🔥🔥🔥