Flashcards in Physiology 1.12 Deck (18):
What populates the subarachnoid space?
Where is CSF produced?
secreted by choroid plexus; turned over 3-4 times per day
What pushes CSF through its path?
spinal cord movements
How does Na+ enter the epithelial cells on the capillary side of the choroid plexus?
How does Na+ enter the ventricles on the ventricular surface of the choroid plexus?
-active Na+/K+ ATPase exchange of Na+ and K+
-Na+ enter the ventricle
How does HCO3- and Cl- enter the ventricles of the choroid plexus?
-HCO3- and Cl- antiporter moves HCO3- into the epithelial cell and Cl- out
-SCO3- forms from hydration of CO2 in the epithelial cell
-HCO3- and Cl- concentrations are higher in epithelial cells and flow down electrochemical gradients into ventricles
Where is the CSF absorbed?
arachnoid villi of the superior saggital sinus
Which volume of CSF does absorption stop in the superior saggital sinus?
Which volume of CSF does absorption equal formation?
What are the functions of the CSF?
-remove brain metabolites
-regulates brain tissue
-adds buoyancy of brain
What is the main difference between brain capillaries versus general capillaries?
-tighter junctions to keep blood in vessel
Where is exchange vessel continuous endothelium found?
skeletal, smooth, cardiac muscle
Where is exchange vessel fenestrated endothelium found?
renal glomerular and peritubular capillaries
Where is exchange-vessel discontinuous endothelium found?
hepatic and bone marrow sinusoids
Where is exchange-vessel tight-junction endothelium found?
What is the Monro-Kellie doctrine?
increase in volume of brain tissue, blood, CSF or other brain fluid will produce increase in intracranial pressue because:
-bony calvarium fixes the total cranial volume
-mass lesions can increase intracranial pressure through associated edema
What are the causes of increased intracranial pressure?
hydrocephalus (increase CSF volume)