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"Een" redirects here. For the nummer, see
1 (nummer)
.
Een
are
organs
o the
veesual seestem
. Thay provide organisms wi
veesion
, the abeelity tae receive an process veesual detail, as weel as enablin several photae response functions that are independent o veesion. Een detect
licht
an convert it intae electro-chemical impulses in
neurons
. In heicher organisms, the ee is a complex
optical
seestem that collects licht frae the surroondin environment, regulates its intensity throu a
diaphragm
,
focuses
it throu an adjustable assemmly o
lenses
tae form an eemage, converts this eemage intae a set o electrical seegnals, an transmits thir signals tae the
harn
throu complex neural pathweys that connect the ee via the
optic nerve
tae the
veesual cortex
an ither auries o the harn. Een wi resolvin pouer hae come in ten fundamentally different forms, an 96% o
ainimal
species possess a complex optical seestem.
[1]
Eemage-resolvin een are present in
molluscs
,
chordates
an
arthropods
.
[2]
The semplest "een", sic as thae in
microorganisms
, dae naething but detect whither the surroondins are licht or
daurk
, that is sufficient for the
entrainment
o
circadian rhythms
.
[3]
Frae mair complex een, retinal
photosensitive ganglion cells
send seegnals alang the
retinohypothalamic tract
tae the
suprachiasmatic nuclei
tae effect circadian adjuistment an tae the
pretectal aurie
tae control the
pupillary licht reflex
.
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