Physiology

Question 1

what are the three layers of the retina from inner to outer?

Answer 1

ganglion cells
bipolar cells
photoreceptors

Question 2

what two lateral connections influence signal processing in the retina?

Answer 2

horizontal cells

amacrine cells

Question 3

what does the photoreceptor cell do?

Answer 3

converts light to neural signals

Question 4

what are the four main regions of the photoreceptor?

Answer 4

outer segment
inner segment
cell body
synaptic terminal

Question 5

which part of the photoreceptor cell contains the receptors?

Answer 5

outer segment

Question 6

which part of the photoreceptor synapses with the bipolar cells?

Answer 6

synaptic terminal cells

Question 7

what are the two types of photoreceptors?

Answer 7

rods

cones

Question 8

what is the membrane potential of a photoreceptor in the dark and why?

Answer 8

depolarised (+)

sodium channel is open in the dark

Question 9

what is the membrane potential of a photoreceptor in the light and why?

Answer 9

hyperpolarised (-)

sodium channel is closed

Question 10

what are visual pigment molecules called?

Answer 10

rhodopsin

Question 11

what is rhodopsin made of?

Answer 11

11-cis-retinal and opsin

Question 12

what effect does light have on rhodopsin?

Answer 12

converts 11-cis-retinal to its active form, all trans retinal

Question 13

what determines visual acuity?

Answer 13

photoreceptor spacing (closer the better)
refractive power

Question 14

what light do rods see?

Answer 14

dim light

Question 15

describe the convergence of rods

Answer 15

high - multiple rods to one ganglion

increased sensitivity to light, decreased visual acuity

Question 16

where are rods found?

Answer 16

equally around the retina

not the fovea

Question 17

what light do cones see?

Answer 17

normal daylight

Question 18

describe the convergence of cones

Answer 18

low - few cones to one ganglion

decreased sensitivity to light, increased visual acuity

Question 19

where are cones found?

Answer 19

concentrated to the fovea

Question 20

how can cones provide colour vision?

Answer 20

they contain different opsins that respond to light of specific wavelengths

Question 21

what three colours can cones see?

Answer 21

red
blue
green

Question 22

what is the visual field of one eye called?

Answer 22

the monocular visual field

Question 23

what is the visual field of both eyes called?

Answer 23

the binocular visual field

Question 24

what divides the retina in half?

Answer 24

the fovea

Question 25

what are the two halves of the retina?

Answer 25

nasal | temporal

Question 26

what happens to the fibres from the nasal retina at the optic chiasma?

Answer 26

cross over to form the optic tracts

Question 27

what is contained in an optic tract?

Answer 27

the nasal and temporal fibres from one eye

Question 28

where does the optic tract pass to?

Answer 28

the lateral geniculate nucleus then the primary visual cortex

Question 29

what is aqueous humour?

Answer 29

a specialised fluid that bathes the structures within the eye

Question 30

what does aqueous humour do?

Answer 30

provides oxygen contains bicarbonate which buffers hydrogen ions

Question 31

where is aqueous humour produced?

Answer 31

the epithelial layer of the ciliary body

Question 32

where is aqueous humour secreted into?

Answer 32

the posterior chamber of the eye

Question 33

where does aqueous humour flow?

Answer 33

into the anterior chamber

Question 34

where does aqueous humour drain?

Answer 34

scleral venous sinus | canal of Schlemm

Question 35

where is the canal of Schlemm found?

Answer 35

the iridocorneal angle

Question 36

what are the two layers of the ciliary epithelium?

Answer 36

PE | NPE

Question 37

what is PE?

Answer 37

a forward continuatio of the pigment epithelium of the retina

Question 38

what is NPE?

Answer 38

non pigmented epithelium

Question 39

what does the basolateral side of the PE face?

Answer 39

the blood

Question 40

what causes raised intra ocular pressure in glaucoma?

Answer 40

imbalance in rate of production and drainage of aqeuous humour

Question 41

what drugs can be used to reduce pressure in glaucoma?

Answer 41

carbonic anhydrase inhibitors

Question 42

name two carbonic anhydrase inhibitors

Answer 42

dorzolamide | acetazolamide