The peripheral nervous system (PNS, or occasionally PeNS) consists of the nerves and ganglia outside of the brain and spinal cord. The main function of the PNS is to connect the central nervous system (CNS) to the limbs and organs. Unlike the CNS, the PNS is not protected by the bone of spine and skull, or by the blood–brain barrier, leaving it exposed to toxins and mechanical injuries. The peripheral nervous system is divided into the somatic nervous system and the autonomic nervous system; some textbooks also include sensory systems. It is also a part of the 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 eleven cranial nerve axons extend beyond the brain and are therefore considered part of the PNS.
Other articles related to "system, peripheral nervous system, nervous system":
... Code Group Subspecialties Focus Allergy and Immunology Allergic reactions, asthma, and the immune system Anesthesiology AN, PAN Surgery Pediatrics, Pain management, Intensive Care, Critical Care, Obstetrics ... changes in the cellular composition of the blood and bone marrow as well as the coagulation system in the blood ... Clinical immunology is concerned with disorders of the immune system and related body defenses ...
... Application of CB2-specific antagonists has found that these receptors are also involved in mediating analgesic effects in the peripheral nervous system ... However, these receptors are not expressed by nociceptive sensory neurons, and at present are believed to exist on an undetermined, non-neuronal cell ...
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... intracranial laceration and haemorrhage due to birth injury (P11) Other birth injuries to central nervous system (P12) Birth injury to scalp (P12.0) Cephalhaematoma due to birth injury (P12.1) Chignon ...
... Focus Allergy and Immunology Allergic reactions, asthma, and the immune system Anesthesiology AN, PAN Surgery Pediatrics, Pain management, Intensive Care, Critical Care ... in the cellular composition of the blood and bone marrow as well as the coagulation system in the blood ... Clinical immunology is concerned with disorders of the immune system and related body defenses ...
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