Week 1 - Physiology

Question 1

function of the choroid plexus

Answer 1

makes CSF - 500-600 / day

Question 2

role of CSF (4)

Answer 2

Supplies with water + amino acids + ions
Removes metabolites
Shock absorbing
pH controls cerebral blood flow

Question 3

describe how plasma becomes CSF ?

Answer 3

passes through the choroid plexus “dialysis”

- ion content (Na + Cl) with water is exchanged for K and glucose

Question 4

what is the foramen between lateral and 3rd ventricles?

Answer 4

Interventricular foramen of Monroe (into the 3rd child lol)

Question 5

what foramen is between 3rd and 4th ventricles?

Answer 5

cerebral aqueduct

Question 6

how does CSF get into the venous system after being secreted into the subarachnoid space?

Answer 6

into the arachnoid villi of dural venous sinuses –> into the superior sagittal sinuses –> venou system

Question 7

what are the three openings out of the 4th ventricle into the subarachnoid space called?

Answer 7

2 x foramen of luschka (l for lateral

1 x foramen of magendie

Question 8

what are 2 bonuses of the BBB?

Answer 8

controls the bp in the brain independently to systemic - keep more stable

protect brain from common bacterial infections + toxins

Question 9

name and describe 3 layers of CNS protection from outer to inner

Answer 9

dura mater - thick, dense, connective tissue

arachnoid mater - delicate. folds down in the longitunidal fissure

pia mater - thin fibrous layer that encloses CSF and blood vessels

Question 10

brain tumour arising from ependymal cells lining the ventricles?

Answer 10

ependtmomas

Question 11

what is an arterial bleed between skull and dura called?

Answer 11

epidural hematoma

Question 12

what is an venous bleed between dura and arachnoid called?

Answer 12

subdural hematoma

Question 13

what is the difference between an epidural vs. subdural hematoma?

Answer 13

epidural = rapid = arterial

subdural = venous = slow

Question 14

what is hydrocephalus ?

Answer 14

accumulating CSF causing enlargement of 1 or more ventricles and increased pressure

Question 15

eye sign of hydrocephalus - why?

Answer 15

papilloedema

optic disc swelling due to high pressure in the subarachnoid space around the optic nerve

Question 16

symptoms of papilloedema ? mild –> severe

Answer 16

blind spot / blurred vision / obscured / loss of vision

Question 17

what makes aqueous humour?

Answer 17

it is formed when plasma “filters” through

Question 18

what are the two parts of the ciliary epithelium?

Answer 18

NPE (inner) - non pigmented

PE (outer)

Question 19

what 2 things are covered by PE and NPE?

Answer 19

ciliary body and posterior surface of the iris

Question 20

how do carbonic anhydrase inhibitors inhibit production of aqueous therefore decrease ocular pressure?

Answer 20

stop bicarbonate ion production… so Na and Cl aren’t drawn into the cell - they normally draw in more WATER

Question 21

what is dorzolamide and what is it used to treat? RoA ??

Answer 21

Dorzolamide is a carbonic anhydrase inhibitor used to treat increased pressure (glaucoma). Given as eye drops.

Question 22

What is acetazolamide and what it is used to treat? Important S/E?

Answer 22

Acetazolamide is a carbonic anhydrase inhibitors which decreases ocular pressure. Given orally and can affect kidneys

Question 23

light signals go straight to the back (photoreceptor cells) and then are processed more as they move forward in Vertical direct transmission. What are the next two parts of “vertical connection”?

Answer 23

1. photoreceptors
2. bipolar cell
3. ganglion cells

Question 24

in addition to the verticle transmission, there is addisional processing from lateral connections. What are the 2 “horizontal” cells?

Answer 24

1. horizontal cell (between photoreceptors + bipolar)

2. amacrine cells (between bipolar and ganglion)

Question 25

what is the neurotransmitter that is involved in vision? (more of it in the dark)

Answer 25

Gluamate !

Question 26

what do you need to have good acuity? (2)

Answer 26

high refractive power

closely spaced photoreceptrtors

Question 27

what do you need to have good sensitivity (ie see in dim lighting) ?

Answer 27

lots of convergence

Question 28

why are rods helpful to see in the dark?

Answer 28

lots of convergence = good sensitivity

rods are widely spread out so give good convergence

Question 29

why are cones helpful to see in the light?

Answer 29

in the light, less convergence is needed, and acuity is more important

cones are close together so give good acuity

Question 30

where in the retina are rods more densely located?

Answer 30

peripheral retina

Question 31

where in the retina are cones more densely located?

Answer 31

central retina (fovea)

Question 32

what type of cones see blue

Answer 32

short ones = short wavelength of blue