Cerebrospinal Fluid and Ventricles Flashcards
WHAT IS PIA MATER
THIN LAYER OF CT ADHERENT TO SURFACE OF CNS PARENCHYMA
- vascularized
WHAT 2 LAYERS OF CT FORM THE LEPTOMENINGES
PIA MATER AND ARACHNOID
WHAT IS ARACHNOID MATER
THIN LAYER OF CT ADHERENT TO DURA BY DESMOSOMES
WHAT DOES SUBARACHNOID SPACE CONTAIN
CSF, BLOOD VESSELS, SPINAL NERVES, ARACHNOID TRABECULAE
WHAT ARE ARACHNOID TRABECULAE
THIN COLLAGENOUS CT EXTENSIONS OF ARACHNOID MEMBRANE
WHAT IS DURA MATER
MOST EXTERNAL, THICK AND FIBROUS CT ADHERENT TO BONE OF SKULL W/IN CRANIAL CAVITY
- separated from vertebra by the epidural space within vertebral canal and contains fat
WHAT IS CEREBROSPINAL FLUID
CLEAR, COLORLESS FLUID PRODUCED BY CHOROID PLEXUSES WITHIN VENTRICLE
FUNCTIONS OF CSF
Surround and permeate the entire CNS
Protects & supports the CNS
Brings in nourishment to the CNS parenchyma
Modulates and regulates intracranial pressure changes
Transport neuroendocrine and neurotransmitters
Maintains ionic balance
CIRCULATION AND ABSORPTION OF CSF
CIRCULATES TO SUBARACHNOID SPACE AND IS ABSORBED BACK TO VENOUS SINUSES
WHERE IS THE CHOROID PLEXUS PRODUCING CSF
LATERAL, 3RD AND 4TH VENTRICLES
ENDOTHELIUM CELLS OF CHOROID CAPILLARIES ARE
FENESTRATED WITH NO TIGHT JUNCTIONS
EPITHELIAL CELLS OF CHOROID PLEXUS
HAVE TIGHT JUNCTION ON VENTRICULAR SURFACE MICROVILLI
WHAT DOES THE COMBINATION OF ENDOTHELIAL CELLS OF CHOROID CAPILLARIES AND EPITHELIAL CELLS OF CHOROID PLEXUS PRODUCE
A SEMI PERMEABLE MEMBRANE
CSF CIRCULATION
CSF circulate from the ventricular system to the subarachnoid space by arterial pulsations of blood in the choroid plexus increases CSF pressure which surges towards the lateral aperture and depend also on the cardiac systole
WHERE IS THE PASSAGE BETWEEN CENTRAL CANAL AND SUBARACHNOID SPACE IN SOME ANIMALS
CONUS MEDULLARIS
WHERE IS THE MAJOR SITE OF CSF ABSORPTION
ARACHNOID GRANULATION
- collection of arachnoid villi in venous sinuses and cerebral veins
WHAT PERMITS FLOW OF CSF INTO LUMEN OF SINUS
ONE WAY VALCE WHEN CSF PRESSURE EXCEEDS VENOUS PRESSURE
HOW DO THE ONE WAY VALVES INTO LUMEN OF SINUS CLOSE
THE ARACHNOID VILLI COLLAPSE WHEN BLOOD PRESSURE EXCEEDS CSF PRESSURE
WHAT ARE THE THREE EXTRA CELLULAR FLUID COMPARTMENTS
PLASMA, CSF AND EXTRACELLULAR FLUID
BLOOD BRAIN BARRIER
BETWEEN PLASMA AND EXTRACELLULAR FLUID OF INTERSTITIAL SPACE AT CAPILLARY LEVEL
WHAT MAKES UP BBB
NONFENESTRATED, ENDOTHELIAL CELL TIGHT JUNCTIONS
- surrounded by thick basement membrane
- layers of astrocyte endfeet processes
WHAT PREVENTS IVERMECTIN FROM CROSSING BBB
p-glycoproteins
FUNCTIONS OF BBB
ISOLATE CNS FROM BLOOD STABLE ENVIRONMENT FOR NEURONAL FUNCTION MODULATE GLUCOSE ENTRY INTO CNS PROTECT NEURONS FROM TOXINS IN BLOOD SELECTIVE BARRIER
WHAT IS THE BLOOD-CSF BARRIER
BARRIER BETWEEN PLASMA AND CSF AT CHOROID PLEXUS
WHAT DOES BLOOD-CSF BARRIER CONSIST OF
TWO CELL LAYER WITH THIN BASEMENT MEMBRANE
- fenestration in vascular endothelial layer and basement membrane
- no tight junctions
cuboidal choroid epithelial layer with tight junctions
WHAT IS THE EPENDYMAL-CSF INTERFACE (PIAL-GLIAL MEMBRANE)
BETWEEN CSF (SUBARACHNOID SPACE) AND EXTRACELLULAR FLUID IN INTERSTITIAL SPACE
WHAT IS THE PIAL-GLIAL MEMBRANE FORMED BY
PIA AND ASTROCYTE FOOT PROCESSES
- permeable, no intercellular junctions
- metabolite in the csf have access to extracellular fluid in parenchyma
WHAT ARE THE EPENDYMAL CELLS LIKE
SQUAMOUS, INCOMPLETE INTERECELLULAR JUNCTION, NO BASEMENT MEMBRANE
