Chapter 13 (1)

    Cards (95)

    • Spinal cord
      Cylinder of nervous tissue that arises from the brainstem at the foramen magnum of the skull, occupies the upper two-thirds of vertebral canal, inferior margin ends at L1 or slightly beyond, averages 1.8 cm thick and 45 cm long, gives rise to 31 pairs of spinal nerves
    • Segment
      Part of the spinal cord supplied by each pair of spinal nerves
    • Spinal cord
      • Conduction - nerve fibers conduct sensory and motor information up and down the spinal cord
      • Neural integration - spinal neurons receive input from multiple sources, integrate it, and execute appropriate output (e.g., bladder control)
      • Locomotion - spinal cord contains central pattern generators: groups of neurons that coordinate repetitive sequences of contractions for walking
      • Reflexes - involuntary responses to stimuli that are vital to posture, coordination and protection
    • Anterior median fissure
      Longitudinal groove on anterior side of spinal cord
    • Posterior median sulcus

      Longitudinal groove on posterior side of spinal cord
    • Regions of the spinal cord
      • Cervical
      • Thoracic
      • Lumbar
      • Sacral
    • Cervical enlargement
      Thicker part of the spinal cord where nerves to the upper limb originate
    • Lumbar enlargement
      Thicker part of the spinal cord where nerves to the pelvic region and lower limbs originate
    • Medullary cone (conus medullaris)

      Spinal cord tapers to a point inferior to lumbar enlargement
    • Cauda equina
      Bundle of nerve roots that occupy the vertebral canal from L2 to S5
    • Meninges
      Three fibrous membranes that enclose the brain and spinal cord: dura mater, arachnoid mater, and pia mater
    • Epidural space
      Space between the dura mater and the vertebrae
    • Subarachnoid space
      Space between the arachnoid mater and the pia mater, filled with cerebrospinal fluid (CSF)
    • Lumbar puncture (spinal tap)

      Procedure to take a sample of cerebrospinal fluid
    • Pia mater
      Delicate membrane that follows the contours of the spinal cord
    • Spina bifida
      Congenital defect in which one or more vertebrae fail to form a complete vertebral arch for enclosure of the spinal cord
    • Spina bifida cystica
      Most serious form of spina bifida
    • Folic acid (a B vitamin now added to flour) is part of a healthy diet for all women of childbearing age – it reduces risk of spina bifida
    • Gray matter
      Neuron cell bodies with little myelin, site of information processing and synaptic integration
    • White matter
      Abundantly myelinated axons that carry signals from one part of the CNS to another
    • Posterior (dorsal) horn

      Part of the gray matter of the spinal cord
    • Posterior (dorsal) root

      Carries only sensory fibers
    • Anterior (ventral) horn

      Part of the gray matter of the spinal cord
    • Anterior (ventral) root
      Carries only motor fibers
    • Gray commissure
      Connects the right and left sides of the gray matter
    • Central canal
      Lined with ependymal cells and filled with cerebrospinal fluid
    • Lateral horn
      Part of the gray matter visible from T2 through L1, contains neurons of the sympathetic nervous system
    • Funiculi
      Three pairs of white matter bundles: posterior (dorsal), lateral, and anterior (ventral)
    • Tracts or fasciculi
      Subdivisions of each funiculus
    • Ascending tracts
      Carry sensory information up the spinal cord
    • Descending tracts
      Carry motor information down the spinal cord
    • Decussation
      Crossing of the midline that occurs in many tracts
    • Contralateral
      When the origin and destination of a tract are on opposite sides of the body
    • Ipsilateral
      When the origin and destination of a tract are on the same side of the body
    • Ascending tracts
      • Gracile fasciculus
      • Cuneate fasciculus
      • Spinothalamic tract
      • Spinoreticular tract
      • Posterior (dorsal) and anterior (ventral) spinocerebellar tracts
    • Gracile fasciculus
      Carries signals from midthoracic and lower parts of body, below T6 it composes the entire posterior funiculus
    • Cuneate fasciculus
      Occupies lateral portion of posterior funiculus at T6 and above, carries signals from upper limb and chest
    • Medial lemniscus
      Tract leading from gracile and cuneate nuclei to thalamus
    • Spinothalamic tract

      Part of the anterolateral system, carries signals for pain, pressure, temperature, light touch, tickle, and itch
    • Spinoreticular tract

      Travels up anterolateral system, carries pain signals resulting from tissue injury
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