ventricles and blood supply to the brain Flashcards
Three meninges
- Dura
- Thick parchment like tissue
- Protection to underlying brain
- Arachnoid
- Thinner fibrous layer
- Not as strong
- Pia
- Thin membrane
- Permeable to CSF
draw diagram and label outer layers of the brain and meninges
role of arachnoid trabeculae
- connective tissue strands which
- provides structure
- keeps pia and arachnoid layers apart
what is arachnoid granulation and role?
- Projects through dural layer
- Forms vesicles
- One way valves into venous sinuses
- Allow flow of CSF through superior sagittal venous sinus
what is falx cerebri
= vertical sheet of dura separating the two cerebral hemispheres
what is tentorium cerebelli
= horizontal sheet of dura separating the occipital cortex and cerebellum
draw and label spinal cord meninges
what are role of denticulate ligaments?
- connect the pia to the arachnoid/dura
- provide stability to the spinal cord
draw and label ventricular system
how does CSF enter the subarachnoid space?
at the median and lateral apertures of the fourth ventricle
how is excess CSF removed?
drained into venous system via the arachnoid granulations
draw the flow CSF
what is CSF synthesised and secreted by?
by choroid plexus which is found in the roof of each of the four ventricles
what is CSF drived from
blood plasma
role of CSF
- flow into venous sinuses
- removes toxic metabolic by-products from the brain
- protects brain from injury
- brain floats in CSF - reduces its weight
Why is lumbar puncture used?
to sample CSF
- for signs of infection or metabolic disturbances within the brain
how is lumbar puncture used to sample CSF?
- Spinal cord ends at L1/L2 vertebra
- Cauda equina below
- Has enlarged subarachnoid space as theres no spinal cord
- Introduce needle at L4/L5
draw and label the blood supply to the brain
vertebral artery
common carotid artery
blood supply to the base of the brain draw and label
which are circle of willis?
role and importance of the circle of willis
When there is a blockage still able to have blood supply to the brain
No damage to the brain
Can go other way of circle of willis
which artery supplies blood to most of the primary sensory and motor cortex?
middle cerebral artery
draw which cortical areas are supplied by which arteries
cortical blood supply:
draw and describe venous drainage of the brain
most sinuses drain into the transverse and sigmoid sinuses
in turn these drain into the internal jugular vein
cavernous sinus drains into the facial vein
clinical importance of facial vein
blood flow is very slow
therefore infection can often occur in cavernous sinus
