Transductance Flashcards
phototransduction
where engery in light waves (photons) stimulate photorecportor cells on the retina
this is whrer light energy is convted electorchemcia reposnse
what is at the base or rods and cones
synaptic ternaiom
do rods and cones contain a neucleous
yes
what makes up rodes and cones outer segmetn
sacks of discs / lamella which have photoreceptors called rhodopsin in rods
what is a a lameella made out of
a cell membarne
what makes up the cell membarne of a lamina in rods
visual pigment rhodospin =
what makes up the cel membare in cones
opsins s, m and l
what are opsin , s, ma and l responsible for
short - s
medium- m
l - large wavelenghts
wher eis opsin and retianl found in rhodosoin
intergal transmemare helical protin
where is vitamen a found in the eye
in the interagl transmemarb helical proin
what type of molcue is vitame a
isomere
what caue vitamen a to isomerise
light falling on it
what type of vitamen a cannot fit in t th eopsin
all trans retincal
what is the opsin
part of the interagl transmemabr helicap proin, the inner part, where retial is
what is the normal type of vitamen a in the eye
11 cis retinal (branched )
how does the viasl pigment result in phototransducation
phototransudion cascaste
what is the role of vit a in the visual pathway
visual regnariton
how is vitamen a mainly absobred
throug diet
what is the effect of vitamen a diffecty
will cause night blindnes, and damge to the normal epithlum
what is the cuase of vit a deficney
malnution
malabsip such as coeliac and spruce
signs of vit a dificeny
bitots sposts on conjuctivy
cornela ulcation
end stage vit a defecy
corneal melating
opopacification of the cornea
what type of cell conects rods to ganglion cell
bipolar nerve cell
what color cones are in tehe eye
red, green and blue
what is retinal
a vitamen a derivative
what is a rhodopsin made of
opsin and retinal
bleaching
when the retial changrs shape due to movement of light and no longer binds to opsin
what is the name of the catin chanesl in rods
cyclic nucleotide gated channels
what do the cyclic neuclotide grated channels do
allow na and ca to enerter
k+ to leak out,
cand voltage gated ca2+ channels
what happens to a rod when it is in darkness to cyclic gmp
cyclic gmp levls become high
what is the noramlm depolaris membaner potenal for rjhodopsin in darkness
-40 mv
how much neruo transmitter is realed at -40 in rhodpsin
there is alot of nurotaimsitor reese
how much nuortramiteor is readxed at -70mv
very little
what is the polarisioan of the cell in light
-70mv
what is retanl converion
where there are multiple rod cells conencted to one bipoalr cell
why is retanl conversion required
as it reduces the threashold for antion pototenal , in low light
low visual aquity
hard to see things in low light
type of pigment in cone cells
iodopsin - this is what gives it ability to sense colour
what type of light intentis cuase idropisn to be broken down
high light instnein
where are cones mainly found
in the forvea
are rods turned on or off with light
off
how many sub using tis rhoedopsin made up of
7
noraml retianl before it is changed
7 cis retainal (i.e. it is bent
what is the staright retial called
all trans retainal
what happens t teh rhodopin after the real hcnate shape
rhodopsin chanes shape
what does transducin do
when retianl chanes shape, it break away form rohdopin and joints to pde
wat does pde do
changes cyclic gmp to regualr gmp
what cause soidum change to open in rod cell
cyclic gmp, so more cyclic gmp mroe soidum enters cell
what happens when light hits on teh soudm chell
it decrease due to reduced cyclic gmp and the rods turn off
what are the 2 types of bioplar cells
light on and light off bipolar cells
light on acitvated by decread decread glutamate dsecion, light on actaved by incerad gluatamt section
what is in an rod tip
lots of opttic discs
are there more rods or cones
rods - about 20 times more
where are rods mainly found
periphally of the eye ball
what vitimen is used to transform all trans retinal to 11cis retihnal
vitamen a
what is done with the bi products of 11cis regneraiton
becomes retinly esters used for retianl epithelum
name for all trans retinal
at rol
name for middle step between all trans retail and 11cis retinal
11 cis rol
name for 11cis retinal
11 cis ral
