Lab Activity 13DefinitionsMeningesSpinal CordSpinal Cord: Conus MedullarisSpinal Cord: Cauda EquinaSpinal Cord: Gray MatterGray Matter HornsSpinal Cord: White MatterWhite Matter ColumnsSpinal Cord StructuresPowerPoint PresentationPoliomyelitisLou Gehrig’s Disease Amyotrophic Lateral SclerosisSpinal Nerves: 31 PairSpinal NervesSpinal NervesNerve PlexusVentral RamiSlide 19Phrenic NerveBrachial PlexusSlide 22Brachial Plexus NervesBrachial Plexus NervesBrachial Plexus NervesSlide 26Lumbar PlexusSlide 28Sacral PlexusSacral PlexusSciatic Nerve BranchesSympathetic Chain GangliaSlide 33Lab Activity 14ReflexesReflex ArcSlide 37Innate ReflexesAcquired ReflexesSlide 40Slide 41Types of ReflexesUpper Motor NeuronsLower Motor NeuronsSlide 45Testing ReflexesStretch ReflexesStretch Reflex Example Patellar Reflex (L2, L3, L4)Slide 49Stretch Reflex Example Ankle Jerk (S1, S2)Stretch Reflex Example Biceps jerk (C5, C6)Grading ReflexesTendon ReflexesSlide 54Flexor ReflexSlide 56Crossed Extensor ReflexSlide 58Cutaneous ReflexesCutaneous Reflexes Plantar ReflexAbnormal Plantar Reflex Babinski’s SignSlide 62The EndLab Activity 13Spinal CordPortland Community CollegeBI 2322Definitions•Tracts: collections of axons in CNS•Nerves:collections of axons in PNS•Ganglia: collections of neuron cell bodies in PNS•Nucleus (nuclei) : collections of neuron cell bodies in CNS3MeningesPia MaterArachnoid MaterDura MaterSubarachnoid Space: contains the spinal fluidSubdural SpaceEpidural Space: out here between the dura mater and the bone4Spinal Cord5Spinal Cord: Conus MedullarisConus MedullarisEnds at the level of L1 or L26Spinal Cord: Cauda EquinaCauda EquinaThese are spinal nerves that extend down the vertebral canal past the level of the spinal cord.7Spinal Cord: Gray MatterAnterior HornPosterior HornCentral CanalThe central “butterfly” is gray matter: it contains cell bodies, dendrites and unmyelinated axons.8Gray Matter Horns•Posterior gray horns contain somatic and visceral sensory nuclei•Anterior gray horns contain somatic motor nuclei•Lateral gray horns (only located in the thoracic and lumbar segments) contain visceral motor nuclei9Spinal Cord: White MatterThe frame around the “butterfly” is white matter: it contains myelinated axons.Posterior White ColumnLateral White ColumnAnterior White ColumnAnterior Median Fissure10White Matter Columns•Each column contains tracts (axons)•Ascending tracts carry sensory information from the body toward the brain•Descending tracts carry motor commands to the spinal cord11Spinal Cord Structures12Dorsal Root(Afferent=Sensory)Dorsal Root Ganglion (Cell bodies of sensory neurons)Posterior (Dorsal)Anterior(Ventral)Ventral Root (Efferent=Motor)Spinal Nerve Mixed motor and sensory.13Poliomyelitis•Polio means gray matter•The polio virus causes inflammation of the gray matter in the anterior horn motor neurons.•These neurons innervate muscles•Symptoms: causes muscle paralysis14Lou Gehrig’s Disease Amyotrophic Lateral Sclerosis•ALS is a genetic disease that causes progressive destruction of anterior horn motor neurons.•Leads to paralysis and death15Spinal Nerves: 31 PairCervical: 8Thoracic: 12Lumbar: 5Sacral: 58 + 12 + 5 + 5 + 1 = 31Coccygeal: 1C1-C7 Emerge above the vertebra for which they are namedC8 Emerges between C7 and T1Thoracic, Lumbar, Sacral and Coccygeal spinal nerves emerge below the vertebra for which they are named16Spinal Nerves17Spinal NervesNerve Plexus•Dorsal and Ventral roots exit the spinal cord and join together to make a spinal nerve•The spinal nerve then splits into dorsal and ventral rami (ramus)•Some ventral rami give off branches to the sympathetic ganglion•The other ventral rami mix and match to make up nerve plexuses18Ventral Rami•The Dorsal Root only contains sensory neurons going toward the spinal cord•The Ventral Root only contains motor neurons going out of the spinal cord•Ventral Rami contain BOTH sensory and motor neurons•As the spinal nerves, rami and plexus are crisscrossing, everything gets mixed around.19Spinal CordDorsal Ramus(mixed)Ventral Ramus(mixed)Rami Communicantes(White ramus + Gray Ramus)Nerve PlexusesVentral Roots (Motor)Spinal Nerve(this is where sensory and motor mix)Dorsal Roots (Sensory)Sympathetic ganglia20Phrenic NervePhrenic Nerve: C3, C4 C5Supplies the diaphragmThe cervical plexus is from C1 to C521Brachial PlexusThe brachial plexus is from C5 to T122Brachial Plexus23Brachial Plexus Nerves•Axillary nerve (C5-C6):•Motor to the deltoid and teres minor muscles•Sensory to the skin of the shoulder•Musculocutaneous nerve (C5-T1)•Motor to the flexor muscles of the arm•Sensory to the lateral surface of the forearm24Brachial Plexus Nerves•Radial nerve (C5-T1)•Motor to muscles of the posterior arm and forearm•Sensory to the posterior-lateral side of the hand, but not the fingers (purple in picture)RadialNerve25Brachial Plexus Nerves•Median nerve (C6-T1): Travels through the carpal tunnel of the wrist•Motor to the flexor muscles on the radial side of the forearm•Sensory to the anterolateral surface (thenar side) of the hand, posterior fingers 1 &2, lateral-posterior finger 3MedianNerve26Brachial Plexus Nerves•Ulnar nerve (C8-T1)•Motor to many flexor muscles of forearm and hand on ulnar side•Sensory to the medial surface of the hand.UlnarNerve27Lumbar PlexusThe Lumbar plexus is from T12 to L428Lumbar Plexus•The major nerves:•Femoral nerve L2-L4 •Motor to Quadriceps group, Pectineus and Iliopsoas muscles, sensory anterior-medial thigh and medial surface of leg and foot.•Injury to femoral nerve causes inability to extend leg & loss of sensation in thigh•Obturator nerve L2-L4 •Motor to adductors of hip. Sensory to medial surface of thigh.•Injury to obturator nerve causes paralysis of thigh adductors29Sacral PlexusThe sacral plexus is from L4 to S430Sacral Plexus•Arises from L4-S4 and serves the buttock, lower limb, pelvic structures, and the perineum•The major nerves:•Sciatic nerve L4–S3 Branches behind the knee: •Common Fibular nerve: Lateral and anterior muscles of the leg•Tibial nerve: Posterior muscles of the leg•Pudendal nerve S2-S4 Muscles of the perineum31Sciatic Nerve Branches•Common fibular nerve injury produces foot drop (inability to dorsiflex foot) or numbness on dorsum of foot•Tibial nerve injury produces dorsiflexion and eversion with loss of sensation on plantar surface of footPopliteal fossaCommon