Central Nervous System III Flashcards
What’s the composition of the CSF?
- Clear and transparent fluid
- Alkaline and does not coagulate
- Pressure = 6-150mm of H2O
- Pressure of CSF is increased in standing, coughing, sneezing, crying, compression of internal Jugular vein
What was Oueckenstedt’s sign?
Used to be used to test for lumbar spinal stenosis (narrowing of the spinal canal, compressing the nerves traveling through the lower back into the legs)
- Now an MRI or CT scan is used
What’s the circulation of CSF?
- Formed in Choroid Plexus of the lateral ventricle
- CSF passes from the lateral ventricle to the 3rd ventricle through FORAMEN OF MONRO
- Passes from the 3rd to the 4th ventricle through the CEREBROL AQUEDUCT (this is aided by the arterial pulsations of the Chroid Plexuses
- 4th ventricle CSF passes to the sub arachnoid space around the brain and spinal cord though the FORAMEN OF MAGENDIE & FORAMINA OF LUSCHKA
What are Arachnoid granulations?
- Projections of the arachnoid membrane (villi) into the dural sinuses that allow CSF to pass from the subarachnoid space into the venous system.
What is the Blood Brain Barrier?
- Protective mechanism that helps maintain a stable environment for the brain and prevents harmful Amino-acids and Ions present in the bloodstream and Blood-cells from entering the brain
What’s the composition of the BBB?
- Endothelium - tight junction
- Thick basal lamina
- Foot processes of Astrocytes
What are the characteristics of the BBB in terms of permeability?
- Water soluble molecules (glucose) are pump mediated
2. Lipid soluble molecules (drugs must be lipid soluble to move into the CNS), Oxygen and H2O can move through
What’s the Cerebrum?
- Largest part of the brain
- Situation in the anterior and middle cranial fossae and the whole concavity of the vault of the skull
What are the 2 parts of the Cerebrum?
- Cerebral hemispheres - left and right
- Diencephalon
- Thalamus, hypothalamus
What are Sulci and Gyri?
- The Cerebral hemispheres are thrown into folds called Gyri in increase the surface area of the brain
- Ssulci are fissures which separate the Gyri
- The Cerebral hemispheres are divided into lobes according to the cranial bones under
1. Central
2. Parieto-occiptial
3. Lateral
What does Grey matter consist of?
- Nerve cells
What does White matter consist of?
Nerve fibres
What are the 5 types of cells within the Grey matter of the Cerebral cortex?
- Horizontal cells
- Stellate cells
- Fusiform cells
- Cells of Martinotti
- Pyramidal cells
What are the 6 Cortical layers of the Cerebral Cortex?
Top
- Molecular layer
- External granular layer
- External pyramidal layer
- Internal grandular layer
- Ganglionic layer (internal pyramidal layer)
- Multiform layer
What is the composition of White matter?
- Myelinated nerve fibres
- Supported by Neuroglia
- Classified into 3 groups according to their connections
1. Commissural fibres
2. Association fibres
3. Projection fibres