Chapter 12: Nervous System
Chapter 12: Nervous System BIOL 103 - 54
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This 0 page Class Notes was uploaded by Demicia Hart on Friday November 6, 2015. The Class Notes belongs to BIOL 103 - 54 at University of Indianapolis taught by Marion Belfils Chaloux in Summer 2015. Since its upload, it has received 35 views. For similar materials see Principles of Human Anatomy in Biology at University of Indianapolis.
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Date Created: 11/06/15
Unit 33 Spinal Cord Spinal Nerves and Special Sens s Spinal Cord 0 General Information Extension of the medulla oblongata that travels through the vertebral canal 1618 inches long Tapers off around the inferior border of L1 vertebra Called the conus medularis The cord is divided into 5 parts Cervical 8 pairs 0 Thoracic 12 pairs Lumbar 5 pairs Sacral 5 pairs Coccygeal 1 pair Creates the total of 31 setspairs of spinal nerves Two enlargements M Lumbosacral Rootlets of L2L5 SlSS Col coccygeal spinal nerve extend from the conus medullaris Called the cauda equina horse s tail This is anchored to the coccyx by the lum terminale terminal linestrand a thin strand of pia mater 0 Protection and Support of the Spinal Cord Meninges involved in the entire nervous system it does not limit itself to iust one o Pia mater o Denticulate ligaments attach to the dura mater to suspend and anchor the spinal cord laterally Arachnoid mater spider web 0 Subarachnoid space Dura mater 0 Provides stability 0 Only one layer 0 Fuses to the connective tissue around the spinal nerves 0 Epidural space houses adipose and areolar connective tissues and blood vessels gtllt 0 Gross Anatomy of the Spinal Cord I Grey matter cell bodies and their associated dendrites glial cells and unmyelinated axons Location inside of the spinal cord 0 Shape like a butter y and like an H o Anterior horns larger portion of the butter y involved in motor functions autonomic and somatic o Posterior horns smaller portion of the butter y involved in sensory information somatic and visceral 0 Lateral horns found only in T1L2 spinal nerves Contains cell bodies of the autonomic motor neurons Anterior median ssure Posterior median sulcus White matter myelinated axons o Organized into anterior posterior and lateral funiculi funiculus is singular o Axons in the funiculus are organized into conducting tracts Spinal Nerves 0 General Information Total of 31 setspairs of nerves Spinal nerves are formed by the joining of anterior ventral and posterior dorsal roots lateral to or after the 0 quotmixedquot nerve Spinal nerves usually have two branches Posterior ramus branches off rst taking care of the erector spinae muscles Anterior ramus Ramus branch Some nerves form a network where the anterior rami weave together These are called plexus There are four major networks in the body Cervical Thoracic Lumbar Sacral Why In case a root is lost o Dermatomes where your brain thinks the pain is H M quotskin cuttingquot a region of skin with sensory innervation from one spinal nerve Clinical relevance Nerve damage Referred pain feeling pain in a location where the pain is not actually happening 0 Example needing an appendectomy but feeling pain around your belly button 0 Thoracic Thoracic spinal nerves are the only nerves that do not form a plexus T1T11 are called the intercostal nerves and they innervated the intercostal muscles 0 Also innervate the abdominal muscles and the overlaying skin T12 is called the o Cervical Plexus C1C4 not C5C8 Innervates anterior neck muscles Scalenes some hyoid muscles Innervates skin on face neck and shoulders o Brachial Plexus C5T1 Supplies the upper limb and the pectoral girdle Ulnar branch 0 Some anterior antebrachial muscles most muscles in hand skin on hand 0 Under the epicondyle of the humerus Radial branch Triceps and anconeus muscles of posterior antebrachium skin Axillary branch Deltoid teres minor skin 0 Where shots are given in the arm Musculocutaneous branch 0 Anterior brachium skin of lateral forearm Medial branch 0 Anterior antebrachial muscles thenar thumb muscles skin Carpal tunnel o Lumbar Plexus L1L4 Less complex but still an anterior and posterior division Supplies sensory and motor information to the interior abdominal wall anterior and medial thigh and skin of the medial leg Longer roots 39 39 Jinnervates muscles of the medial thigh Lateral femoral cutaneous takes care of muscles on the lateral thigh Genitofemoral Tabe 145 o Sacral Plexus L4S4 Anterior and posterior division Gluteal nerves control the gluteal muscles 0 Superior and inferior Sciatic 0 In ammation of the sciatic nerve o Thickest nerve in vour bodv M o M 0 Common Fibular nerve Super cial Deep Tabe 146