chapter 2 Flashcards
(57 cards)
is a window into the
central nervous system
Cerebrospinal fluid (CSF
Cerebrospinal fluid is of diagnostic value because its composition can
give clues to the nature of neurologic diseases of virus origin
functions of cerebrospinal fluid
Physical support and protection
Cerebrospinal fluid can be sampled by
lumbar
Where within the central nervous system is cerebrospinal fluid located?
- the ventricles of the brain
- the central canal of the spinal cord
- the subarachnoid spaces surrounding the brain and spinal cord
Where is the Lateral ventricles found
Situated in the lower medial portion of each cerebral hemisphere
Separated by a thin septum
Each lateral ventricle consists of a body, an anterior horn, and posterior horn that extends into the occipital lobe of the brain
where is the third ventricle located
A thin centrally placed cleft below the body of the lateral ventricles
the third ventricle Communicates with the lateral ventricles through the
Foramen of Monro
the third ventricle Communicates with the fourth ventricles through the
the Aqueduct of Sylvius (Central Aqueduct)
what is the fourth ventricle
- An enlargement of the Aqueduct of Sylvius
- Forms a space in the pons and medulla of the brain
- Narrows to form the central canal of the spinal cord
what is the meninges
Beneath the bony shell of the cranium lie 3 protective tissue
layers that cover the CNS
what are the three meninges
Dura mater outermost layer
Arachnoid layer middle layer
Pia mater inner layer
from the meninges:
what layer is the
(Dura mater )
outermost layer
from the meninges:
what layer is the
(Arachnoid layer)
middle layer
from the meninges:
what layer is the
(Pia mater)
inner layer
where do the meninges extend to ?
They extend down the brainstem and the spinal cord
what is the The Subarachnoid Space ?
is the space between the arachnoid layer and pia mater that is filled with cerebrospinal fluid
It is within the choroid plexus that cerebrospinal fluid is produced from the
plasma of the blood
CSF is not
a simple filtrate of plasma
CSF production is the result of
active transport by the choroidal epithelium to make the CSF a fluid unique from blood plasma
what are the 4 functions of the cerebrospinal fluid
- Physical support and protection
- Excretion mechanism for metabolic products
- Intracerebral transport
- Maintenance of a stable immunosuppressive “microenvironment” within the CNS
Maintenance of a stable immunosuppressive “microenvironment” within the CNS
csf
Helps to maintain the CNS as an immune-privileged site
Serves to distribute biologically active substances within the CNS ( central nerves system) such as hormones and other neuroactive substances (e.g., cytokines and neuropeptides involved in maintaining the immune privilege of brain)
csf
Intracerebral transport
Physical support and protection
> Provides buoyancy for the brain
> When suspended in CSF, a 1500 gm brain with a water content of 80% weighs only 50 gm due to specific gravity of brain vs CSF
> Protective because CSF volume fluctuates reciprocally with changes in intracranial blood volume when skull is intact
> csf Provides a cushioning function for brain during head trauma
