BBB and CSF Flashcards
Name the meninges? (found both in brain and spinal cord)
Dura mater (Hard outer part) - Periosteal and meningeal layers
Arachnoid mater
Pia mater
What protects the brain? (3 parts)
Hair skin and cranium
Meninges
CSF
Name the two main dural folds and what they seperate?
Tentorium Cerebelli - (Brainstem and cerebellum from the occipital lobes of the cerebrum) Falx cerebri ( Seperates the two hemishpheres)
How are the dural veins different from normal veins? (2)
- The veins have no valves
- Veins have no normal vessels layers (tunica media, adventia and externa)
(The dural veins make up the sinuses that drain the CSF)
Where is the CSF made?
Made in choroid plexus of the lateral part of the 3rd and 4th Ventricles
What does the CSF fill?
The ventricles of the brain and the subarachnoid spaces
How much CSF is produced every day? What is the normal amount?
500ml per day. Normal is 150ml.
Function of the CSF? (3)
- Proetcts the neuranl structures
- Forms a protective buoyancy (Makes the brain weigh 1/30th of weight so 50g from 1400g)
- Transports chemicals, nutrients, and removes waste
How is CSF different to blood plasma? (4)
- No red blood celss
- Few white blood cells (little immune fucntion)
- Very few proteins
- Its is clear (as glucose makes 50% of serum)
Describe the flow of the CSF?
Produced travels to, and goes, what it does and how its removed
- Produced in the chorid plexus of 3rd ventricle
- Travels down to the 4th ventricle
- Into the subarachnoid space and spinal cord
- Travels along and removes waste products and provides buoyancy
- Excess CSF absorbed by the arachnoid villi
- Drains into the superior sagittal sinus
Where is a lumbar puncture given?
Given at L4 - between end of spinal cord and beginning of the cauda equina
What is hydrocephalus?
Water in the brain which blocks flows, it is due to accumulation of pus in the meninges.
What is the function of the BBB? And how is carried out?
Stops blood contents from leaking and affecting the brain, by astrocyte foot process which from tight junctions which limit permeability.
What is a foot process?
It is formed from the astrocyte and capillary interaction which froms the tight junctions in BBB.
What is meningitis? (Which Matters affected)
Infection of the meninges (pia and arachnoid mater),
How is the CSF different in normal, bacterial and viral meninges?
Appearance
N- Clear
B- Turbid
V - Clear
Treatment for meningits?
IMMEDIATE intravenous or intramuscular BENZYLPENICILLIN
(If bacteria identified in CSF give specific antibiotic
Complication of meningitis?
Seizure, shocks, and Cerebral Oedema (Risk herniation or raised intracranial pressure)
What are the two types of Meningococcal disease?
- Meningococcal Meningitis
2. Meningococcal Septicaemiea (Blood Poisononing)
Describe the action of meningococcal septicaemia? (4)
- Meningococcal bacteria rlease endotoxins which increase capillary permeability
- Reduces the blood flow
- Bad clotting as loos of clotting factors (Vitamin K epoxide reductase)
- Haemorrgae due to leaky blood vessels
Which serogroup of meningococcal bacteria is the cause of 80% of all meningitis and symptoms
80% is B in children under 4. causes headaches vomitting fever
What is the second most common cause of meningitis?
Pneumonal Meningitis by streptococcus pneumoniae.
List three other types of Meningitis
- Ecoli - In newborns and babies under 3 months
- Hib - Eliminated due to vaccine
- Tuberculous - caused by myobacterium tuberculous (Developing countries and HIV +)
By what Bacteria is congenital Hydrocephalus caused?
due to infection in utero by protozan taxoplasma gondii
Most Common meningitis
Viral
Most Severe Meningitis but less common
Bacteria
How is the CSF different in normal, bacterial and viral meninges?
Cell count
N- less than 5
B- more than 200
V- 50-200
How is the CSF different in normal, bacterial and viral meninges?
Proteins
N- less than 0.45g
B- more than 1.5g
V- less than 1g
How is the CSF different in normal, bacterial and viral meninges?
Glucose as % of serum
N- 50-65% of serum
B- low
V- >50% of serum
What are the different serogroups of Meningicoccal Meningitis? (5)
A B C W and Y.
Meningitis Pathophysiology Ie what areas do the organisms cross
due to organism that cross the BBB or the choroid plexus
