lec 15.docx - Chapter 13/14 – Part 1: The Central Nervous...

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Chapter 13/14 – Part 1: The Central Nervous SystemCentral Nervous System (CNS)The central Nervous System (CNS) controls most functions of the body and mind.It consists of two parts: the brain and the spinal cord.The brain is the center of our thoughts, the interpreter of our external environment, and theorigin of control over the body.Regions and Organization of the CNSThe general pattern of the CNS is a central cavity surrounded by grey matter (mostly neuron cellbodies) external to which is white matter (myelinated fiber tracts)Spinal cordShows this basic pattern of a central cavity surrounded by gray matterExternal white matter composed of myelinated fiber tractsBrainThe brain also shows a similar pattern though it shows additional areas of gray matter:The cerebral hemispheres and cerebellum have an outer gray matter layer calledthecortexCortex disappears in brain stemScattered gray matter nuclei are seen among the white matterRegions and Organization of the BrainThe adult brain can be divided into four major regions:1.Cerebral hemispheres2.Diencephalon3.Brain stem (midbrain, pons, and medulla)4.CerebellumVentricles of the BrainThe ventricles are a set of four cavities in the brain where the cerebrospinal fluid (CSF) isproduced.The ventricles are connected to one another and to the central canal of spinal cordThey are filled with cerebrospinal fluid (CSF) and lined byependymal cells
Lateral ventriclesare paired, C-shaped ventricles found in the cerebral hemispheres.Separated anteriorly by septum pellucidum.TheThird ventricleis in the diencephalonTheFourth ventricleis in the hindbrainApertures in the ventricles connect the ventricles to thesubarachnoid space– a fluidfilled space surrounding the brainCerebral HemispheresThe cerebral hemispheres form the most superior part of the brain – together they make up~83% of total brain mass.The cerebral hemispheres show surface markingsRidges (gyri), shallow grooves (sulci), and deep grooves (fissures)Longitudinal fissureSeparates two hemispheresTransverse cerebral fissureSeparates cerebrum and cerebellumCerebral HemispheresFive lobes of the cerebrum:FrontalParietalTemporalOccipitalInsulaThe cerebral hemispheres consist of the three basic regions:oCerebral cortex

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Term
Fall
Professor
Mark Danley

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