© 2015 Pearson Education, Inc. Lecture Presentation by Lee Ann Frederick University of Texas at Arlington Chapter 13 The Spinal Cord, Spinal Nerves, and.

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1 © 2015 Pearson Education, Inc. Lecture Presentation by Lee Ann Frederick University of Texas at Arlington Chapter 13 The Spinal Cord, Spinal Nerves, and Spinal Reflexes

2 © 2015 Pearson Education, Inc. Introducción a Nervios y Reflejos Espinales Objetivos Describir los componentes principales de un nevio espinal Relacionar los patrones de distribucion con las regiones que inervan Introducir los patrones principales de piscinas neuronales Describir los pasos de un reflejo y la clasificacion de reflejos

3 © 2015 Pearson Education, Inc. Introducción a Nervios y Reflejos Espinales Reflejos espinales Respuestas nerviosas rapidas, automaticas activadas por un estimulo específico Controlados por el cordon espinal solamente, sin intervención del cerebro

4 © 2015 Pearson Education, Inc. Figure 13-1 An Overview of Chapters 13 and 14. CHAPTER 14: The Brain CHAPTER 13: The Spinal Cord Sensory receptors Sensory input over cranial nerves Reflex centers in brain Motor output over cranial nerves Muscles Effectors Glands Adipose tissue Sensory receptors Sensory input over spinal nerves Motor output over spinal nerves Reflex centers in spinal cord

5 © 2015 Pearson Education, Inc. 13-2 Cordón Espinal Anatomía Gruesa 18 pulgadas (45 cm) ½ pulgada (14 mm) Termina entre L 1 y L 2 Simetría bilateral Zurcos dividen el cordón en lados derecho e izq Posterior mediano zurco – posterior Anterior mediana fisura – mas profundo anterior

6 © 2015 Pearson Education, Inc. 13-2 Cordón espinal EL nervio espinal A cada lado de la espina Donde se unen las raices: dorsal y ventral Mixtos Transportan tanto fibras aferentes como eferentes

7 © 2015 Pearson Education, Inc. Figure 13-3a The Spinal Cord and Spinal Meninges. a A posterior view of the spinal cord, showing the meningeal layers, superficial landmarks, and distribution of gray matter and white matter White matter Ventral rootlets of spinal nerve Ventral root Dorsal root Dorsal root ganglion Dorsal rootlets of spinal nerve Gray matter Spinal nerve Meninges Pia mater Arachnoid mater Dura mater

8 © 2015 Pearson Education, Inc. Figure 13-3b The Spinal Cord and Spinal Meninges. b A sectional view through the spinal cord and meninges, showing the relationship of the meninges, spinal cord, and spinal nerves Dura mater Meninges Pia mater Arachnoid mater Vertebral body Subarachnoid space Rami communicantes Autonomic (sympathetic) ganglion Ventral root of spinal nerve Ventral ramus Dorsal ramus Dorsal root ganglion Denticulate ligament Adipose tissue in epidural space Spinal cord POSTERIOR ANTERIOR

9 © 2015 Pearson Education, Inc. 13-2 Cordón Espinal Meninges Membranas aislantes para el cordón Funciones: Protección Vascularizacion Carrying blood supply Conectar con las craneales Meningitis Infección Viral o bacteriana

10 © 2015 Pearson Education, Inc. 13-2 Cordon Esponal Tres meninges 1. Dura mater externa 2. Arachnoid mater intermedia 3. Pia mater interna

11 © 2015 Pearson Education, Inc. 13-2 Cordón espinal The Dura Mater Fuerte firbrosa Cranealmente se funde con el periosto occipital Continua con la craneal Caudalmente Se convierte en fibras Se une en el filo terminal con el ligamento coccígeo Espacio epidural Entre paredes del canal y la dura madre Anestesia epidural

12 © 2015 Pearson Education, Inc. 13-2 Cordón Espinal Aracnoide Recubierta por membrana Aracnoidea Epitelio escamoso simple Espacio Subdural Entre aracnoide y dura madre Subaracnoideo Entre aracnoide y pia madre Circulacion del (CSF)

13 © 2015 Pearson Education, Inc. 13-2 Cordon Espinal Líquido Cerebrospinal (CSF) Gases, nutrientes y desechos s Punción Lumbar Pia Mater Interna Colageno y elastina Pegada al cerebro

14 © 2015 Pearson Education, Inc. Figure 13-4 The Spinal Cord and Associated Structures. Anterior median fissure Pia mater Denticulate ligaments Spinal cord Dorsal root Ventral root, formed by several “rootlets” from one cervical segment Arachnoid mater (reflected) Dura mater (reflected) Spinal blood vessel

15 © 2015 Pearson Education, Inc. Figure 13-5a The Sectional Organization of the Spinal Cord (Part 1 of 2). Dorsal root ganglion Lateral white column Posterior gray horn Lateral gray horn Anterior gray horn Anterior white column Posterior white column a The left half of this sectional view shows important anatomical landmarks, including the three columns of white matter. The right half indicates the functional organization of the nuclei in the anterior, lateral, and posterior gray horns.

16 © 2015 Pearson Education, Inc. Figure 13-5a The Sectional Organization of the Spinal Cord (Part 2 of 2). Posterior median sulcus Posterior gray commissure Somatic Visceral Somatic Visceral Ventral root Sensory nuclei Motor nuclei The cell bodies of neurons in the gray matter of the spinal cord are organized into functional groups called nuclei. Functional Organization of Gray Matter Anterior gray commissure Anterior white commissure Anterior median fissure a The left half of this sectional view shows important anatomical landmarks, including the three columns of white matter. The right half indicates the functional organization of the nuclei in the anterior, lateral, and posterior gray horns.

17 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Anatomia de Nervios Espinales Cada segmento del cordón espinal Esta conectado a un par de nervios Cada Nervio espinal: Esta rodeado por tres capas de tejido conectivo Suplen vascularización

18 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Tres capas de tejido conectivo que rodean cada nervio 1. Epineuro Externa Densa red de fibras de colágeno 2. Perineuro Intermedia Divide los nervios en fascículos 3. Endoneuro Interna Rodea axones individuales

19 © 2015 Pearson Education, Inc. Figure 13-6a A Peripheral Nerve. a A typical peripheral nerve and its connective tissue wrappings Fascicle Myelinated axon Schwann cell Endoneurium Perineurium (around one fascicle) Epineurium covering peripheral nerve Connective Tissue Layers Blood vessels

20 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Nervios Periferales Salen por foramenes intervertebrales y se ramifican Ramo gris no mielina, retorno de ganglio simpático Ramos blanco, dorsal y ventral Sensoriales y Motores Blanco- hacia el ganglio simpático Dorsal – somático y viscerales, espalda Ventral – extremidades y ventrolateral

21 © 2015 Pearson Education, Inc. Figure 13-8 Peripheral Distribution of Spinal Nerves (Part 2 of 2). The spinal nerve forms just lateral to the intervertebral foramen, where the dorsal and ventral roots unite. 1 3 4 5 6 7 2 1 The ventral root of each spinal nerve contains the axons of somatic motor and visceral motor neurons. Visceral motor nuclei Somatic motor nuclei = Visceral motor commands = Somatic motor commands KEY Postganglionic fibers to smooth muscles, glands, visceral organs in thoracic cavity Sympathetic ganglion Preganglionic fibers to sympathetic ganglia innervating abdominopelvic viscera A sympathetic nerve contains preganglionic and postganglionic fibers innervating structures in the thoracic cavity. The gray ramus communicans contains preganglionic fibers that innervate glands and smooth muscles in the body wall or limbs. These fibers are unmyelinated and have a dark gray color. Gray rami are associated with each spinal nerve. The white ramus communicans is the first branch from the spinal nerve and carries visceral motor fibers to a nearby sympathetic ganglion. Because these preganglionic axons are myelinated, this branch has a light color and is therefore known as the white ramus. White rami are only found between T 1 and L 2. Rami communicantes Postganglionic fibers to smooth muscles, and glands of body wall, limbs To skeletal muscles of body wall, limbs The axons in the relatively large ventral ramus supply the ventrolateral body surface, structures in the body wall, and the limbs. The dorsal ramus contains somatic motor and visceral motor fibers that innervate the skin and skeletal muscles of the back. Dorsal root ganglion Dorsal root To skeletal muscles of back Postganglionic fibers to smooth muscles, glands, etc., of back

22 © 2015 Pearson Education, Inc. Figure 13-8 Peripheral Distribution of Spinal Nerves (Part 1 of 2). From interoceptors of back From exteroceptors, proprioceptors of back The dorsal ramus carries sensory information from the skin and skeletal muscles of the back. 3 2 The ventral ramus carries sensory information from the ventrolateral body surface, structures in the body, wall, and the limbs. From exteroceptors, proprioceptors of body wall, limbs From interoceptors of body wall, limbs Rami communicantes KEY 1 The sympathetic nerve carriers sensory information from the visceral organs. From interceptors of visceral organs Ventral root Visceral sensory nuclei Dorsal root ganglion Somatic sensory nuclei The dorsal root of each spinal nerve carriers sensory information to the spinal cord. 4 = Visceral sensations = Somatic sensations

23 © 2015 Pearson Education, Inc. Figure 13-7 Dermatomes. N V C 2 –C 3 C2C2 C3C3 C4C4 C3C3 C4C4 C5C5 C5C5 T1T1 T2T2 T2T2 T2T2 T7T7 T3T3 T4T4 T5T5 T6T6 T8T8 T9T9 T 10 T 11 T 12 T2T2 T1T1 T2T2 T7T7 T3T3 T4T4 T5T5 T6T6 T8T8 T9T9 T 10 T 11 T 12 C6C6 C7C7 C6C6 C7C7 C8C8 T1T1 C8C8 L1L1 L2L2 L3L3 L4L4 L5L5 L1L1 L2L2 L3L3 L4L4 L1L1 S2S2 S1S1 S2S2 S3S3 S4S4 S5S5 L5L5 L1L1 L2L2 L3L3 L5L5 L4L4 S1S1 ANTERIOR POSTERIOR KEY Spinal cord regions = Cervical = Thoracic = Lumbar = Sacral Dermatomas Regiones en la piel, bilaterales Vigiladas por pares específicos de nervios espinales Neuropatia periferal Perdida regional de funciones sensoriales o motoras Debido a compresión o traumas

24 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Plexos Red compleja de fibras nerviosas entrelazadas Controla musculos esqueletales en el cuello y extremidades Principalmente fibras de la rama ventral Los cuatro plexos mayores ventrales 1. Cervical 2. Braquial 3. Lumbar 4. Sacral

25 © 2015 Pearson Education, Inc. Figure 13-9 Peripheral Nerves and Nerve Plexuses (Part 1 of 2). Cervical plexus Brachial plexus C2C2 C3C3 C5C5 T1T1 T2T2 T7T7 T3T3 T4T4 T5T5 T6T6 C1C1 C4C4 C6C6 C7C7 C8C8 T8T8 T9T9 T 10 T 11 Lesser occipital nerve Great auricular nerve Transverse cervical nerve Supraclavicular nerve Phrenic nerve Axillary nerve Musculocutaneous nerve Thoracic nerves C1-C5 C5-T1

26 © 2015 Pearson Education, Inc. Figure 13-9 Peripheral Nerves and Nerve Plexuses (Part 2 of 2). T 12 Lumbar plexus Sacral plexus L1L1 L2L2 L2L2 L3L3 L4L4 L5L5 S1S1 S2S2 S3S3 S4S4 S5S5 Co 1 Radial nerve Ulnar nerve Median nerve Iliohypogastric nerve Ilioinguinal nerve Lateral femoral cutaneous nerve Genitofemoral nerve Femoral nerve Obturator nerve Gluteal nerves Superior Inferior Pudendal nerve Saphenous nerve Sciatic nerve T12-L4 L4-S4

27 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Cervical Incluye nervios espinales C 1 –C 5 Inerva cuello, cavidad toracica y diafragma Nervio principal Frénico (controla el diafragma)

28 © 2015 Pearson Education, Inc. Figure 13-10 The Cervical Plexus (Part 1 of 2). Cranial Nerves Nerve Roots of Cervical Plexus Accessory nerve (N XII) Hypoglossal nerve (N XII) C2C2 C1C1 C3C3 C4C4 C5C5 Clavicle

29 © 2015 Pearson Education, Inc. Figure 13-10 The Cervical Plexus (Part 2 of 2).

30 © 2015 Pearson Education, Inc. Figure 13-10 The Cervical Plexus (Part 2 of 2).

31 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Braquial Incluye nervios espinal C 5 –T 1 Cintura escapular y extremidades superiores Principales Musculocutáneo Mediano Ulnar Axillar Radial

32 © 2015 Pearson Education, Inc. Figure 13-11a The Brachial Plexus.

33 © 2015 Pearson Education, Inc. Figure 13-11a The Brachial Plexus.

34 © 2015 Pearson Education, Inc. Figure 13-11b The Brachial Plexus.

35 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Lumbar Incluye nervios espinales T 12 –L 4 Principales Genitofemoral Femoral

36 © 2015 Pearson Education, Inc. Figure 13-12a The Lumbar and Sacral Plexuses.

37 © 2015 Pearson Education, Inc. Figure 13-12a The Lumbar and Sacral Plexuses.

38 © 2015 Pearson Education, Inc. 13-4 Nervios Espinales y Plexos Sacral Incluye nervios espinales L 4 –S 4 Principales Pudendal Ciático 1. Fibular 2. Tibial

39 © 2015 Pearson Education, Inc. Figure 13-12b The Lumbar and Sacral Plexuses. Superior Gluteal Sacral Plexus Spinal Segments Nerve and Distribution L 4 –S 2 Gluteus minimus, gluteus medius, and tensor fasciae latae muscles Sacral plexus, anterior view b Nerve Roots of Sacral Plexus The sacral plexus is formed by a branch from L 4 and ventral rami of L 5 –S 4. L4L4 Inferior Gluteal Posterior Femoral Cutaneous Sciatic Pudendal L 4 –S 2 L 4 –S 3 S 1 –S 3 S 2 –S 4 Gluteus maximus muscle Skin over perineum and posterior thigh and leg Semimembranosus, semitendinosus, and adductor magnus muscles; branches into tibial and fibular nerves Muscles of the perineum; skin over external genitalia, bulbospongiosus and ischiocavernosus muscles L5L5 Sacrum Lumbosacral trunk L5L5 S1S1 S2S2 S3S3 S4S4 S5S5 Co 1

40 © 2015 Pearson Education, Inc. Figure 13-12c The Lumbar and Sacral Plexuses. Nerves of the lumbar and sacral plexuses, anterior view c Iliohypogastric nerve Ilioinguinal nerve Genitofemoral nerve Lateral femoral cutaneous nerve Femoral nerve Obturator nerve Superior gluteal nerve Inferior gluteal nerve Pudendal nerve Posterior femoral cutaneous nerve (cut) Sciatic nerve Saphenous nerve Common fibular nerve Superficial fibular nerve Deep fibular nerve

41 © 2015 Pearson Education, Inc. Figure 13-12d The Lumbar and Sacral Plexuses. Nerves of the sacral plexus, posterior view d Inferior gluteal nerve Common fibular nerve Sural nerve Tibial nerve Pudendal nerve Posterior femoral cutaneous nerve Sciatic nerve Superior gluteal nerve

42 © 2015 Pearson Education, Inc. 13-5 Piscinas Neuronales (Grupos) Organizacion funcional Sensoriales 10 millones Llevan información hacia el SNC Motoras Medio millón Llevan informacion, comandos a efectores periferales Interneuronas 20 billones Funciones de alto nivel

43 © 2015 Pearson Education, Inc. 13-5 Piscinas Neuronales Cinco patrones de Circuitos Neuronales 1. Divergencia Distribuyen información 2. Convergencia Recogen información 3. Procesamiento en serie Mueve informacion en una linea 4. Procesamiento paralelo Mueve informacion por varias rutas simultáneamente 5. Reverberacion Mecanismo de retroalimentacion positiva

44 © 2015 Pearson Education, Inc. Figure 13-13a Neural Circuits: The Organization of Neuronal Pools. a Divergence A mechanism for spreading stimulation to multiple neurons or neuronal pools in the CNS Figure 13-13d Neural Circuits: The Organization of Neuronal Pools.

45 © 2015 Pearson Education, Inc. Figure 13-13b Neural Circuits: The Organization of Neuronal Pools. b Convergence A mechanism for providing input to a single neuron from multiple sources

46 © 2015 Pearson Education, Inc. Figure 13-13c Neural Circuits: The Organization of Neuronal Pools. c Serial processing A mechanism in which neurons or pools work sequentially

47 © 2015 Pearson Education, Inc. Figure 13-13d Neural Circuits: The Organization of Neuronal Pools. Parallel processing d A mechanism in which neurons or pools process the same information simultaneously

48 © 2015 Pearson Education, Inc. Figure 13-13e Neural Circuits: The Organization of Neuronal Pools. e Reverberation A positive feedback mechanism

49 © 2015 Pearson Education, Inc. 13-6 Reflejos Reflejos Respuestas automáticas, rápidas, coordinadas aun estímulo, en el cordón espinal Interconecciones de neuronas sensoriales interneuronas y motoras

50 © 2015 Pearson Education, Inc. 13-6 Reflejo Respuestas rápidas, y automáticas a un estímulo específico 1:1 - Un reflejo produce una respuesta motora Arco reflejo La ruta por la que viaja de un reflejo simple Receptor  efector Generalmente retroalimentación negativa, se oponen al estímulo

51 © 2015 Pearson Education, Inc. 13-6 Reflejos Cinco pasos del reflejo Llega el estímulo, activa el receptor Estímulo cambio químico o físico Activación de neurona sensorial Depolarización de grado Procesamiento en neurona postsináptica Liberación de NTs de la presináptica Activación de la neurona motora Potencial de acción Respuesta de efector periferal Activada por NTs

52 © 2015 Pearson Education, Inc. Figure 13-14 Spinal Reflexes (Part 1 of 4). Arrival of stimulus and activation of receptor Activation of a sensory neuron Dorsal root Sensation relayed to the brain by axon collaterals Spinal cord Receptor Stimulus Effector Response by a peripheral effector Activation of a motor neuron Ventral root REFLEX ARC KEY Sensory neuron (stimulated ) Excitatory interneuron Motor neuron (stimulated) Information processing in the CNS 3 2 4 5 1

53 © 2015 Pearson Education, Inc. 13-6 Reflejos Clasificación Clasificación de los reflejos de acuerdo a: 1.Desarrollo temprano 2.Respuesta motora 3.Complejidad del circuito 4.Lugar de procesamiento

54 © 2015 Pearson Education, Inc. 13-6 Reflejos Clasificación Desarrollo Innatos Desarrollados antes de nacer Adquiridos Patrones aprendidos Rapidos automáticos Respuesta motora En que consiste la respuesta, en activar que cosa: Somáticos Control involuntario del sistema nervioso Piel, mucosas, tendones, estiramientos, patelar Viscerales (autonómicos) Controla otros sistemas fuera del muscular

55 © 2015 Pearson Education, Inc. 13-6 Reflejos Clasificación Complejidad del circuito neural Monosinápticos Neurona sensorial  Neurona motora Polisinápticos Al menos una interneurona entre la sensorial y la motora Lugar de procesamiento Espinales Se procesa en el cordón espinal Craneales Se procesa en el cerebro

56 © 2015 Pearson Education, Inc. Figure 13-15 The Classification of Reflexes. Learned Control skeletal muscle contractions Include superficial and stretch reflexes One synapse Spinal Reflexes Cranial Reflexes Monosynaptic Polysynaptic Somatic Reflexes Visceral (Autonomic) Reflexes Innate Reflexes Acquired Reflexes Reflexes can be classified by developmentresponsecomplexity of circuitprocessing site Control actions of smooth and cardiac muscles, glands, and adipose tissue Multiple synapses (two to several hundred) Processing in the brain Genetically determined Processing in the spinal cord

57 © 2015 Pearson Education, Inc. 13-7 Espinales Aumentan en nivel de complejidad Monosinapticos Polisinapticos Intersegmentarios Varios segementos Respuestas que varian en complejidad

58 © 2015 Pearson Education, Inc. 13-7 Espinales Monosinapticos De Estiramientos De sensorial a motora Poco retraso Receptor : huso muscular

59 © 2015 Pearson Education, Inc. Figure 13-14 Spinal Reflexes (Part 2 of 4). Response REFLEX ARC Stimulus Stretch Receptor (muscle spindle) Contraction Effector Spinal cord Sensory neuron (stimulated) Motor neuron (stimulated) KEY

60 © 2015 Pearson Education, Inc. Figure 13-16 A Muscle Spindle. Extrafusal fiber Sensory region Intrafusal fiber Muscle spindle Gamma efferent from CNS To CNS

61 © 2015 Pearson Education, Inc. 13-7 Espinales Posturales Estiramientos Postura erecta Músculos que se estiran reaccionan contrayéndose y se mantiene un balance Tensión acumulada, fatiga muscular

62 © 2015 Pearson Education, Inc. 13-7 Espinales Polisinapticos Complicados Interneuronas Balance entre EPSP e IPSP

63 © 2015 Pearson Education, Inc. 13-7 Espinal De Retirada Alejar una parte del cuerpo del lugar del estimulo Flexor Retirar la mano de algo caliente Fuerza y duración de respuesta Depende de intensidad del estimulo Ipsilaterales vs Contralateral

64 © 2015 Pearson Education, Inc. Figure 13-14 Spinal Reflexes (Part 3 of 4). Painful stimulus Flexors stimulated Extensors inhibited Distribution within gray horns to other segments of the spinal cord Ipsilaterales Ocurren en el mismo lado donde ocurre el estimulo Estiramiento, tendones, de retirada

65 © 2015 Pearson Education, Inc. Figure 13-14 Spinal Reflexes (Part 4 of 4). Flexors stimulated Extensors inhibited Flexors inhibited Extensors stimulated Painful stimulus Sensory neuron (stimulated) Excitatory interneuron Motor neuron (stimulated) Motor neuron (inhibited) Inhibitory interneuron KEY To motor neurons in other segments of the spinal cord Reflejo extensor cruzado Contralateral En el lado opuesto al estímulo Simultaneo coordinado con flexor Flexor recoje la pierna Extensor estira la otra pierna Para sostener el peso

66 © 2015 Pearson Education, Inc. 13-8 El Cerebro puede alterar los reflejos espinales Babinski Normal en infante Anormal en adulto Puede indicar daño al SNC en adultos

67 © 2015 Pearson Education, Inc. Figure 13-17a The Babinski Reflexes. The plantar reflex (negative Babinski reflex), a curling of the toes, normal in healthy adults.

68 © 2015 Pearson Education, Inc. Figure 13-17b The Babinski Reflexes. The Babinski sign (positive Babinski reflex) occurs in the absence of descending inhibition. It is normal in infants, but pathological in adults.