CSF

• What percentage of the human brain is fluid?

  80%
• What is the primary fluid in the human brain?

  Cerebrospinal fluid (CSF)
• How much CSF is formed daily?

  500 milliliters
• Where is CSF formed in the brain?

  By the choroid plexus
• What areas does CSF flow into?

  Ventricles and subarachnoid spaces
• What must equal the rate of CSF formation in steady state?

  Movement of fluid to venous blood
• What are the key characteristics of CSF?

  • Clear, colorless fluid
  • Volume: 150 ml
  • Specific gravity: 1.004 - 1.007
  • Alkaline reaction, does not coagulate
  • Cell count: 0 - 3 /mm³
  • Pressure: 0 - 15 mmHg
• What is the normal pressure of CSF?

  0-15 mmHg
• What happens to CSF pressure when standing up or coughing?

  It increases
• What is the total volume of CSF in the body?

  70-120 ml
• How often is CSF replaced?

  A few times each day
• Where does CSF absorption occur?

  In the superior sagittal sinus
• What do arachnoid villi do?

  Allow CSF to flow into the bloodstream
• What happens when CSF pressure is greater than venous pressure?

  CSF flows into the bloodstream
• What is the blood-CSF barrier?

  A barrier preventing large molecules from entering CSF
• What can damage the blood-CSF barrier?

  Inflammation
• What are the functions of CSF?

  • Shock absorber
  • Mechanical buffer
  • Cushion between brain and cranium
  • Reservoir regulating cranial contents
  • Medium for nutritional exchange
  • Transport hormones
  • Remove metabolic waste
• Who first observed the blood-brain barrier?

  Paul Ehrlich
• What did Lewandowsky's experiments demonstrate?

  Neurotoxic agents affect brain function when injected directly
• When was the term "blood-brain barrier" coined?

  1913
• What do tight junctions in brain capillaries prevent?

  Solute movement between endothelial cells
• What induces tight junction formation in brain capillaries?

  Paracrine signals from astrocytes
• What complications are related to CSF?

  • Brain edema
  • Hemorrhage
  • Meningitis
  • CSF rhinorrhea
• What is hydrocephalus?

  CSF buildup within the ventricles
• What can cause hydrocephalus?

  Overproduction of CSF or obstruction
• What is a lumbar puncture also called?

  Spinal tap
• Why must a patient lie down after a lumbar puncture?

  To prevent a spinal headache
• What is CSF mainly used to diagnose?

  Meningitis
• What other conditions can CSF help diagnose?

  Conditions of the brain and spinal cord