Reticular formation extends through the central core

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Reticular Formation= extends through the central core of the medulla oblongata, pons andmidbrain.a.Maintains cerebral cortical awareness via the Reticular Activating Systemb.Filters out repetitive or weak stimulic.Helps regulate skeletal and visceral muscle activity.F.The Spinal Cord1.The adult spinal cord measures approximately 45 cm (18 inches) in length and has a maximumwidth of roughly 14 mm (0.55 inch). The spinal cord is located within the vertebral foramen(also known as the vertebral canal).2.Anatomy of the Spinal CordA. Thecervical enlargementsupplies nerves to the shoulder and upper limbs.B. Thelumbar enlargementprovides innervation to the structures of the pelvis and lowerlimb.C. Theconus medullarisis the tapered, conical portion of the spinal cord inferior to thelumbar enlargement.D.Because the adult spinal cord ends at the level of the first or second lumbar vertebra, thedorsal and ventral roots of the spinal segments L2and S5extend inferiorly. When seen ingross dissection, the filum terminale and the long ventral and dorsal roots resemble ahorse’s tail. Hence, this complex is called thecauda equina.E. Thefilum terminaleis a slender strand of fibrous tissue that extends from the tip of theconus medullaris to the second sacral vertebra. It provides longitudinal support to thespinal cord as a component of the coccygeal ligament.F.Theposterior mediansulcusis a shallow longitudinal groove on the posterior (ordorsal) surface of the spinal cord.G. Theanterior median fissureis a deep groove along the anterior (ventral) surface.H. Thecentral canalis a longitudinal passageway that extends the length of the spinal cordthat contains cerebrospinal fluid.I.The spinal cord contains gray matter and white matter:1.Thegray matter, dominated by the cell bodies of neurons, neuroglia, andunmyelinated axons, surrounds the narrow central canal and forms a butterflyshape. The gray matter can be organized into structural and functional areas:a.Structural Organization: The projections of gray matter toward the outersurface of the spinal cord are calledhorns.i.Theposterior gray horncontains somatic and visceral sensorynuclei.ii.Thelateral gray horn(located only in the thoracic and lumbarsegments) contains visceral and motor nuclei.iii.Theanterior gray horncontains somatic motor nuclei.b.Functional Organization: The cell bodies of the neurons in the gray matterof the spinal cord are organized into functional groups callednuclei.i.Sensory nuclei: receive and relay sensory information from thereceptors of the body to the CNS.ii.Motor nuclei: issue motor commands to the peripheral effectors.2.The superficialwhite mattercontains large numbers of myelinated andunmyelinated axons. Like gray matter, white matter is also divided intofunctional and structural areas:a.Structural Organization: The structural components of white mater aredivided intocolumns.i.Theposterior white columnlies between the posterior gray hornsand posterior median sulcus.ii.The

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