10 Questions
Where is the cerebrospinal fluid primarily formed?
In the choroid plexus
What is the main function of the arachnoid villi?
To reabsorb cerebrospinal fluid into the venous blood
What happens to the cerebrospinal fluid pressure when a small amount of fluid is removed during a spinal tap?
It decreases
How often is the cerebrospinal fluid replaced in a day?
More than three times
What is the approximate volume of cerebrospinal fluid in the central nervous system?
125 - 150 mL
What is the primary function of cerebrospinal fluid in the brain?
To act as a shock-absorbing fluid to prevent the brain from bumping against the skull
What is the result of excess cerebrospinal fluid accumulation in the brain?
Brain damage and mental retardation if untreated
What is the significance of the tight junctions in the blood-brain barrier?
They prevent the exchange of materials between the blood and the brain
What is the composition of cerebrospinal fluid compared to plasma?
Lower in K+ concentration and higher in Na+ concentration
What is the purpose of surgically shunting excess cerebrospinal fluid to veins elsewhere in the body?
To treat hydrocephalus
Study Notes
Cerebrospinal Fluid
- Cerebrospinal fluid (CSF) is a special fluid that surrounds the central nervous system (CNS).
- CSF is primarily formed by the choroid plexus, found in the ventricles of the brain.
- Choroid plexus consists of richly vascularized masses of pia mater tissue that projects into pockets formed by ependymal cells.
- CSF flows through the 4 interconnected ventricles in the brain and the spinal cord's central canal.
- CSF escapes through small openings from the 4th ventricle into the subarachnoid space, surrounding the brain and spinal cord.
- CSF is reabsorbed into the venous blood through the arachnoid villi, maintaining a pressure of about 10mmHg.
Functions of Cerebrospinal Fluid
- CSF serves as a shock-absorbing fluid, cushioning the brain from bumps against the skull.
- CSF has a similar density to the brain, allowing it to suspend the brain in its fluid environment.
- CSF facilitates exchange of materials between the body fluid and the brain.
- CSF composition influences the brain interstitial fluid, with a lower K+ concentration and higher Na+ concentration.
Blood-Brain Barrier
- The blood-brain barrier is a highly selective barrier that regulates exchange between the blood and the brain.
- The barrier consists of anatomical and physiological factors.
- Capillary walls in the brain have tight junctions, sealing the wall and preventing free exchange of plasma components.
- The blood-brain barrier shields the brain from harmful changes in the blood, while allowing essential ions to move down the concentration gradient for nerve impulse conduction.
Learn about the cerebrospinal fluid, its formation, and flow within the brain and spine. Explore the role of choroid plexus and ventricles in this process.
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