Physiology

Question 1

What cells produce CSF?

Answer 1

Secretory epithelial cells found within the choroid plexus of the lateral ventricles.

Question 2

How does CSF flow?

Answer 2

Formed in the ventricles, circulates the subarachnoid space, then resorbed at the arachnoid granulations.

Question 3

What are the 3 major functions of the CSF?

Answer 3

Mechanical protection
Homeostatic protection
Circulation (acts as a medium for exchange between the blood and the brain)

Question 4

Neutrophils present in the CSF is suggestive of which diagnosis?

Answer 4

Bacterial meningitis

Question 5

Lymphocytes present in the CSF is suggestive of which diagnosis?

Answer 5

Viral meningitis

Question 6

Which circulation is found below the basolateral membrane of the ependymal cells (which line the lateral ventricles)?

Answer 6

Blood

Question 7

Which circulation is found below the apical membrane of the ependymal cells (which line the lateral ventricles)?

Answer 7

CSF

Question 8

What connects the lateral and 3rd ventricles?

Answer 8

Foramen of Monroe

Question 9

What connects the 3rd and 4th ventricles?

Answer 9

Aquaduct of sylvius

Question 10

Where is the only point of exchange between the CSF and venous blood supply?

Answer 10

Superior saggital sinus

Question 11

What is the role of the blood-brain barrier?

Answer 11

Protect the brain from bacterial infection/toxins.

However, it does make it tricky to deliver drugs to the CNS.

Question 12

What is hydrocephalus?

Answer 12

Accumulation of the CSF in the ventricular system, resulting in the enlargement of one or more ventricles.

May be due to obstruction or overproduction.

Question 13

What is papilloedema?

Answer 13

Swelling of the optic disc due to increased ICP

Pressure effect is transmitted from the subarachnoid space.

Question 14

How may papilloedema present?

Answer 14

Enlarged blindspot
Blurring
Loss of sight

Question 15

What is the aqueous humor?

Answer 15

A specialised fluid that bathes the structures of the eye, providing oxygen, metabolites, and bicarbonates.

Question 16

How does bicarbonate help in the eye?

Answer 16

Buffers acidity produced by the cornea and lens (these structures undergo anaerobic glycolysis).

Question 17

What is the route taken by the aqueous humor through the eye?

Answer 17

Produced in ciliary body > Posterior chamber > Anterior chamber > Scleral venous sinuses

Question 18

How does inhibition of carbonic anhydrase impact aqueous humor production?

Answer 18

Decreases volume secreted

An example of a carbonic anhydrase inhibitor is dorzolamide.

Question 19

Where is the visual cortex located?

Answer 19

The occipital lobe

Question 20

Failure to address strabismus (wandering eye) in newborns can result in what?

Answer 20

Amyblyopia

Question 21

More of which compound is released by photoreceptors when it is dark?

Answer 21

Glutamate

Question 22

Which cell type is responsible for vision in dim light?

Answer 22

Rods

Found dispersed around the retina.

Question 23

Where are retinal cones concentrated within the eye?

Answer 23

Fovea

These are responsible for normal daylight vision.

Question 24

What retinal cell type has a low convergence

Answer 24

Cones

Only one or few cones supply images to each ganglion cell.

Results in a sharper signal, thus greater visual acuity.

Question 25

What retinal cell type has a high convergence?

Answer 25

Rods

Signals are received from a wider area, as many rods supply a single ganglion. Produces a less sharp visual acuity.

Question 26

What is the difference between the vision produced by rods and cones?

Answer 26

Rods have greater sensitivity

Cones have greater acuity

Question 27

What cell type is responsible for colour vision?

Answer 27

Cones

Different forms exist at various frequencies of the visual part of the EM spectrum.