What is the Ventricular System?
it is a group of cavities in the brain, full of CSF
What are the 4 cavities in the brain?
2 lateral ventricles, 3rd ventricle, and 4th ventricle
Where does the 4th ventricle drain?
to the central canal (where a spinal tap is done in the lumbar region).
Where does the anterior (frontal) horn extend?
the frontal lobe
Where does the posterior (occipital) horn extend?
the occipital lobe
Where does the inferior (temporal) horn extend to?
the temporal lobes
What area of the brain is central to Alzheimer’s disease and memory function?
hippocampus
What connects the lateral ventricle to the 3rd ventricle?
Foramen of Monro
What connects the 3rd to the 4th ventricle?
Cerebral Aqueduct
What allows fluid to flow into the subarachnoid space?
Foramen of Luschka and Foramen of Magendie
Which foramen are below the 4th ventricle?
Foramen of Luschka and Foramen of Magendie
What comes right off of the 4th ventricle?
the Central Canal
What is a cistern?
collection space (for CSF)
Where is the CSF that goes around the cerebellum?
Cistern Magna
What is the 4th bodied cistern above the cerebellum?
Quadrageminal Cistern
What is between the pons and cerebellum?
Cerebellum Ponteen
How does CSF get from the ventricles to the subarachnoid space?
Foramen of Luschka and Foramen of Magendie
How does CSF flow into the cisterns?
From the subarachnoid space
What has a harder time crossing the BBB?
Water soluble & larger molecules
What happens if the cerebral aqueduct gets blocked?
Pressure builds first in 3rd and lateral ventricles which leads to hydrocephalis
What happens if the cerebellum fails to grow?
Ageminus - the 4th ventricle looks really big
What is Dandy-Walker Syndrome?
Coordination problems mainly, goes undetected a lot… congenital brain malformation involving the cerebellum, 4th ventricle enlarges.
What are the 3 functions of the CSF?
- physical support of the brain (support when head is shaken)
- Excretory function & regulation of the chemical environment
- Channel for chemical communication with in the CSF (throughout the brain)
About how much CSF do you gotssss (at any given time)?
140 mL a day, but produce 500 mL a day.
What is most CSF produced by?
choroid plexus
When CSF barrier prevents contamination of CSF, what is it absorbed by?
Arachnoid Villa
What are the two main types of glial cells?
- Microglia
2. Macroglia
What do glial cells do?
provide metabolic support & structure
What is the ratio of glial cells to neurons?
10:1
What do microglia cells do?
phagocytes/scavengers that rapidly mobilize and activate in response to pathological conditions
What do macroglial cells do?
provide support and nutritive functions.
What are the 4 types of Macroglial cells?
- Oligodendrocytes
- Schwann Cells
- Astrocytes
- Ependymal Cells
What forms the myelin sheath?
- Oligodendrocytes
2. Schwann Cells
What do Astrocytes do?
act as scaffolds for growing axons, monitor synaptic actions, provide chemical feedback, contribute to BBB.
What do Ependymal Cells do?
line fluid-filled cavities, regulate flow of chemicals from these cavities into the brain.
What does Myelin do?
Speeds up transmition
What are the Nodes of Ranvier?
Break in myelin (the gaps)
What are the 3 types of subcortical white matter?
- Projection fibers
- Association fibers
- Commissural fibers
What are the Projection Fibers?
Motor and Sensory fibers that…
What are the ASSociation Fibers?
complex processing… Go from one side of the hemisphere to the other of the same hemisphere.
What are the Commissural Fibers?
anterior and posterior commissures, corpus callosum.
What is the difference between white and gray matter?
White - myelinated axons
Gray - cell bodies