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Cards In This Set
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Cerebrospinal Fluid
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A clear, colorless liquid composed primarily of water that protects the brain and spinal cord from chemical and physical injuries
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Cerebrospinal Fluid circulates through cavities in the brain and spinal cord and around the brain and spinal cord in the ________ space
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Subarachnoid
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What is the total volume of CSF in an adult?
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80 to 150 mL ( or 3 to 5 oz )
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The CSF filled cavities in the brain are called __________
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Ventricles
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Anteriorly, the lateral ventricles are separated by a thin membrane called the __________
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Septum pellucidum
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What are the three basic functions of CSF?
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- Mechanical Protection- Homeostatic Function- Circulation
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Describe the mechanical protection properties of the CSF
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It serves as a shock absorbing medium that protects the delicate tissues of the brain and spinal cord from jolts that would otherwise cause them to hit the bony walls of the cranial cavity and vertebral canal. Also buoys the brain so that it "floats" in the cranial cavity
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Describe the Homeostatic Function of CSF
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PH of the CSF affects pulmonary ventilation and cerebral blood flow, which is important in maintaining homeostatic control for brain tissue. CSF also serves as a transport system for polypeptide hormones secreted by hypothalamic neurons that act at remote sites in the brain
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Describe the circulation function of CSF
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CSF is a medium for minor exchange of nutrients and waste products between the blood and adjacent nervous tissue
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The majority of CSF production is from the _________
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Choroid Plexuses
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What are the choroid plexuses?
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Networks of blood capillaries in the walls of the ventricles
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What covers the capillaries of the choroid plexus?
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Ependymal cells joined by tight junctions
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Why can materials entering CSF from choroid capillaries not leak between the ependymal cells?
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Tight junctions
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What permits certain substances to enter the CSF but excludes others?
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The blood-cerebrospinal fluid barrier
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How is the blood-cerebrospinal fluid barrier different from the blood-brain barrier?
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The blood-brain barrier is formed mainly by tight junctions of brain capillary endothelial cells, while the blood-cerebrospinal fluid barrier is formed by tight junctions of ependymal cells
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