صفحه محصول - پاورپوینت نخاع و اعصاب نخاعی

پاورپوینت نخاع و اعصاب نخاعی (pptx) 51 اسلاید

دسته بندی : پاورپوینت

نوع فایل : PowerPoint (.pptx) ( قابل ویرایش و آماده پرینت )

تعداد اسلاید: 51 اسلاید

قسمتی از متن PowerPoint (.pptx) :

12- 2 Spinal Cord and Spinal Nerves Chapter 12 12- 3 Spinal Cord Extends from foramen magnum to second lumbar vertebra Segmented Cervical Thoracic Lumbar Sacral Connected to 31 pairs of spinal nerves All are mixed nerves; I.e., contain both sensory and motor fibers Not uniform in diameter throughout length Cervical enlargement : supplies upper limbs Lumbar enlargement : supplies lower limbs Conus medullaris : tapered inferior end. Cauda equina : origins of spinal nerves extending inferiorly from lumbosacral enlargement and conus medullaris. 12- 4 Spinal Meninges Dura mater : outermost layer; continuous with epineurium of the spinal nerves No firm connections to vertebrae Epidural space : external to the dura; anesthesia injected here in sc. Contains blood vessels, areolar connective tissue and fat. Arachnoid mater : delicate net-work of collagen and elastic fibers Subarachnoid space : between pia and arachnoid CSF and blood vessels within web-like strands of arachnoid tissue Fluid functions as a shock absorber Pia mater : thin layer of elastic and collagen fibers bound tightly to surface of brain and spinal cord Denticulate ligaments extend from pia through arachnoid to dura; prevent lateral movement Forms the filum terminale , which anchors spinal cord to coccyx and the denticulate ligaments that attach the spinal cord to the dura mater 12- 5 Cross Section of Spinal Cord 12- 6 Cross Section of Spinal Cord Anterior median fissure and posterior median sulcus: deep clefts partially separating left and right halves Gray matter: contains neuron cell bodies, dendrites, axons Divided into: Posterior (dorsal) horns Anterior (ventral) horns Lateral horns (found only in thoracic and lumbar regions White matter Myelinated axons Three columns (funiculi): ventral, dorsal, lateral Each of these divided into sensory or motor tracts 12- 7 Organization of Gray Matter 1. Posterior gray horns - contain somatic and visceral sensory cells bodies (SS and VS in diagram) 2. Anterior horns - contain somatic motor cell bodies (SM) 3. Lateral horns - located ONLY in thoracic and lumbar regions contain visceral motor cell bodies 12- 8 Organization of White Matter Divided into three funiculi (columns) – posterior, lateral, and anterior Each column contains several fiber tracts (bundles of axons) All axons with a tract relay the same information in the same direction Ascending tracts - carry sensory information toward the brain Descending tracts - carry motor commands to spinal cord Fiber tract names reveal their origin and destination 12- 9 Cross section of Spinal Cord, cont. Commissures: connections between left and right halves Gray with central canal in the center White Roots: spinal nerves arise as rootlets then combine to form roots Dorsal (posterior) root has a ganglion Ventral (anterior)-no ganglion Two roots merge laterally and form the spinal nerve 12- 10 Organization of Neurons in Spinal Cord and Spinal Nerves Dorsal root ganglion : collections of cell bodies of unipolar sensory neurons forming dorsal roots. Motor neuron cell bodies are in anterior and lateral horns of spinal cord gray matter. No ganglion formed Multipolar somatic motor neurons in anterior (motor) horn Autonomic neurons in lateral horn Axons of motor neurons form ventral roots and pass into spinal nerves