Peripheral Nervous System Lecture Notes PDF

‫‪Peripheral nervous‬‬ ‫‪system‬‬ ‫محاضرة ‪ -11‬مرحلة اولى – تشريح عملي‬  Peripheral nervous system The network of nerves branching out throughout the body from the brain and spinal cord is called the peripheral nervous system. In addition to the 31 pairs of spinal nerves...

‫‪Peripheral nervous‬‬ ‫‪system‬‬ ‫محاضرة ‪ -11‬مرحلة اولى – تشريح عملي‬  Peripheral nervous system The network of nerves branching out throughout the body from the brain and spinal cord is called the peripheral nervous system. In addition to the 31 pairs of spinal nerves mentioned in the slides on the spinal cord there are 12 pairs of cranial nerves that attach to the brain 1- The olfactory nerve carries sensory input for smell. 2- The optic nerve carries sensory input for vision. 3- The oculomotor nerve controls muscles of the eye and eyelid. 4- The trochlear nerve controls the eyeball.  Cranial nerves 5- The trigeminal nerve controls the face, nose, mouth, forehead, top of head, and jaw. 6-. The abducens nerve also controls the eyeball. 7- The facial nerve controls muscles of the face and scalp, and part of the tongue for sense of taste. 8- The cochlear nerve provides sensory input for hearing and equilibrium.  Cranial nerves 9- The glossopharyngeal nerve controls saliva, swallowing, and taste. 10- The vagus nerve is the longest cranial nerve, extending to and controlling the heart, lungs, stomach, and intestines. 11- The accessory nerve permits movement of the head and shoulders. 12- The hypoglassal nerve controls the muscles of the tongue.  Spinal Nerves Cervical plexus (C1 - C4): most branches are cutaneous and supply the skin of face and neck. Other branches supply muscles of the anterior neck. Fibers of C3/ 4/5 cervical nerves form the right and left phrenic nerve, which supply the diaphragm. Brachial plexus (C5 – T1): a) Musculcutaneous nerve: supply arm and skin of forearm. b) Ulnar nerve: supply muscles of forearm, hands and skin of hands. c) Median nerve: supply muscles of the forearm and muscles of hands.  Spinal Nerves Lumbosacral plexus (T12 - S5): a) Obturator nerve: supply the Adductor muscles of the thigh. b) Femoral nerve: supply quadriceps muscles. c) Sciatic nerve: divides into tibial and common peroneal nerve. It supply muscles and skin in the thighs, legs, and feet. It is the largest and longest nerve in the body. Other nerves associated with lumbar plexus are: d) Pudendal nerve: supply the muscles of perineum. e) Inferior & superior gluteal nerve: supply the gluteal muscles and the tensor fascia lata muscle.  What does the peripheral nervous system do? peripheral nervous system has two main subsystems: autonomic and somatic. Autonomic: These are nervous system processes brain runs automatically and without you thinking about them, such as sweating, gland secretions, blood pressure, and the heart. It is divided into the ‘sympathetic’ and ‘parasympathetic’ divisions. The sympathetic nervous system is responsible for the ‘flight or fight’ responses… increased alertness, metabolic rate, respiration, blood pressure, heart rate, and sweating and a decrease in digestive and urinary function. The parasympathetic nervous system counteracts the responses of the sympathetic system and restoring homeostasis.  Somatic Somatic: These are functions you manage by thinking about them. Senses: PNS is a key part of how brain gets information about the world around you. This job falls under the somatic nervous system. Movement: peripheral nerves deliver command signals to all the muscles in body that you can consciously control. This job also falls under the somatic nervous system.