LE 4: Meninges, CSF, BBB, BV of brain

what are the meningeal layers of the nervous system from superficial to deep

periosteal dura, meningeal dura, arachnoid, pia

Dura mater: characteristics, components (2)

tough and fibrous, made of CT

Includes Dural venous sinuses which collect blood from the brain

Also includes subdural space, which is empty and serves as a potential space for blood pooling in case of injury

Arachnoid mater: characteristics, component (and function of component)

epithelial tissue, thin and transparent

includes arachnoid granulations, which collect CSF and return it to blood, which helps maintain the fluid balance of the body and prevents the excess of CSF that may crush the brain.

Pia mater: Characteristics and components (1)

thin, delicate epithelial tissue

contains BV that supply the spinal cord

Dural folds: function, divisions, locations of divisions

divide and support brain regions

tentorium cerebri: separates cerebrum and cerebellum

falx cerebri: separates halves of cerebrum

falx cerebelli: separates halves of cerebellum

Functions (3) and locations of CSF (4)

buoyancy

protection: cushions and slows movement of brain

chemical stability: removes waste from nervous tissue and circulates nutrients

located within ventricles, subarachnoid space, canals, and bathing the surface of the brain

CSF flow: enablers and pattern

enabled by its own fluid pressure gradient, the pulsation of the brain caused by the heartbeat, and motion of ependymal cells lining the choroid plexus

pattern: lateral ventricle, intraventricular foramen, third ventricle, cerebral aqueduct, fourth ventricle, central canal (or fourth ventricle, apertures, subarachnoid space, arachnoid granulation, blood)

What produces CSF and where

CSF is produced by choroid plexus in the ventricles of the brain.

a choroid plexus is a collection of capillaries and its ependymal cells

What forms the Blood CSF barrier

tight junctions binding ependymal cells

What forms the Blood Brain barrier

tight junctions binding endothelial cells that line capillaries, the basement membrane of endothelial cells, and the perivascular feet of astrocytes

What is the function of the Brain Barrier system

selective transport, preventing the entrance of harmful substances into the extracellular fluid of the brain

What can pass the BBB, what cant, and what can somewhat

-glucose, water, nicotine, alcohol, anesthetics

-cancer drugs, antibiotics, proteins

-NA, K, Cl

What are the vessels that supply oxygen to the brain, and what happens if they are disrupted

the internal jugular vein, the internal carotid artery, and the vertebral artery

damage can result in LOC and permanent brain damage

How is CSF produced

by filtering blood

Where is the BBB absent or reduced and why

at circumventricular organs in the third and fourth ventricles, ex. medulla oblongata

this allows these organs to monitor blood composition