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Opthalmology > Physiology > Flashcards

Flashcards in Physiology Deck (24):
1

What sites of the brain do not have a BBB

pinneal gland
cirumventricular organs

2

Where is CSF produced

n the secretory epithelium of the choroid plexus

3

What is contained in normal CSF

it is clear and colourless
contains little protein
little immunoglobulins

4

What is hydrocephalus

accumulation of CSF in the ventricular system or around the brain
susequent enlargement of one or more ventricles and increase in CSF

5

What is normal pressure hydrocephalus

triad of dementia, incontinence and gait disturbances

6

What is idiopathic intracranial hypertension

condition seen in obese females usually of childbearing age
can cause papilloedmea, headaches etc
no imaging features of hydrocephalus

7

What is the purpose of the aqueous humour

a specialised fluid that bathes the structures within the eye
procides oxygen and metabolites and contains bicarbonate

8

What is the function of bicarbonate in the aqueous humour

buffers the protons produces in the cornea and the lens

9

What are the two epithelial layers in the ciliary body and posterior surface of the iris

the pigment epithelium of the retina
the non pigmented epithelium layer

10

What happens when photoreceptors are exposed to light

they hyperpolarise
they are usually depolarised

11

What enables the brain tp perceive light

the change in sodium with light (sodium channels closed in light and open in dark)

12

What is different about photoreceptors compared to other neurons

they are usually at a depolarised resting membrane potential of -20 compared to -70 of most cells

13

What happens to sodium channels when exposed to light

they close

14

what happes to the membrane potential with light exposure

hyperpolarises

15

What effect does light have on the visual pigment molecules

light converts 11 cis retinal to all trans retinal (vit A)

16

What increases your visual acuity

cones

17

What is used to see in dim light

rods

18

Which has more convergence -rods or cones

rods

19

What is used to see colour

cones

20

Where are cones and rods situated

rods - periphery
cones- central retina (fovea)

21

What colour do short wave cones see

blue

22

What colour do middle wave cones pick up

green

23

What colour do long wave cones percieve

red

24

What tumours affect the production of CSF

colloid cysts
Pinealoma
Ependymomas (children usually)
Choroid plexus tumours (children usually)