Physiology Flashcards
What cells produce CSF?
Secretory epithelial cells found within the choroid plexus of the lateral ventricles.
How does CSF flow?
Formed in the ventricles, circulates the subarachnoid space, then resorbed at the arachnoid granulations.
What are the 3 major functions of the CSF?
Mechanical protection
Homeostatic protection
Circulation (acts as a medium for exchange between the blood and the brain)
Neutrophils present in the CSF is suggestive of which diagnosis?
Bacterial meningitis
Lymphocytes present in the CSF is suggestive of which diagnosis?
Viral meningitis
Which circulation is found below the basolateral membrane of the ependymal cells (which line the lateral ventricles)?
Blood
Which circulation is found below the apical membrane of the ependymal cells (which line the lateral ventricles)?
CSF
What connects the lateral and 3rd ventricles?
Foramen of Monroe
What connects the 3rd and 4th ventricles?
Aquaduct of sylvius
Where is the only point of exchange between the CSF and venous blood supply?
Superior saggital sinus
What is the role of the blood-brain barrier?
Protect the brain from bacterial infection/toxins.
However, it does make it tricky to deliver drugs to the CNS.
What is hydrocephalus?
Accumulation of the CSF in the ventricular system, resulting in the enlargement of one or more ventricles.
May be due to obstruction or overproduction.
What is papilloedema?
Swelling of the optic disc due to increased ICP
Pressure effect is transmitted from the subarachnoid space.
How may papilloedema present?
Enlarged blindspot
Blurring
Loss of sight
What is the aqueous humor?
A specialised fluid that bathes the structures of the eye, providing oxygen, metabolites, and bicarbonates.
How does bicarbonate help in the eye?
Buffers acidity produced by the cornea and lens (these structures undergo anaerobic glycolysis).
What is the route taken by the aqueous humor through the eye?
Produced in ciliary body > Posterior chamber > Anterior chamber > Scleral venous sinuses
How does inhibition of carbonic anhydrase impact aqueous humor production?
Decreases volume secreted
An example of a carbonic anhydrase inhibitor is dorzolamide.
Where is the visual cortex located?
The occipital lobe
Failure to address strabismus (wandering eye) in newborns can result in what?
Amyblyopia
More of which compound is released by photoreceptors when it is dark?
Glutamate
Which cell type is responsible for vision in dim light?
Rods
Found dispersed around the retina.
Where are retinal cones concentrated within the eye?
Fovea
These are responsible for normal daylight vision.
What retinal cell type has a low convergence
Cones
Only one or few cones supply images to each ganglion cell.
Results in a sharper signal, thus greater visual acuity.
What retinal cell type has a high convergence?
Rods
Signals are received from a wider area, as many rods supply a single ganglion. Produces a less sharp visual acuity.
What is the difference between the vision produced by rods and cones?
Rods have greater sensitivity
Cones have greater acuity
What cell type is responsible for colour vision?
Cones
Different forms exist at various frequencies of the visual part of the EM spectrum.
