Preferred Label : iris;
Uberon definition : the adjustable membrane, composed of the stroma and pigmented epithelium, located
just in front of the crystalline lens within the eye;
Uberon related term : irises; irides; anterior uvea;
Uberon Homology note : The eye of the adult lamprey is remarkably similar to our own, and it possesses numerous
features (including the expression of opsin genes) that are very similar to those
of the eyes of jawed vertebrates. The lamprey's camera-like eye has a lens, an iris
and extra-ocular muscles (five of them, unlike the eyes of jawed vertebrates, which
have six), although it lacks intra-ocular muscles. Its retina also has a structure
very similar to that of the retinas of other vertebrates, with three nuclear layers
comprised of the cell bodies of photoreceptors and bipolar, horizontal, amacrine and
ganglion cells. The southern hemisphere lamprey, Geotria australis, possesses five
morphological classes of retinal photoreceptor and five classes of opsin, each of
which is closely related to the opsins of jawed vertebrates. Given these similarities,
we reach the inescapable conclusion that the last common ancestor of jawless and jawed
vertebrates already possessed an eye that was comparable to that of extant lampreys
and gnathostomes. Accordingly, a vertebrate camera-like eye must have been present
by the time that lampreys and gnathostomes diverged, around 500 Mya.[well established][VHOG];
Uberon Taxon note : The avian iris and ciliary body undergoes a transition from smooth-to-striated muscle
during embryonic development [DOI:dx.doi.org/10.1006/dbio.1998.9019];
Origin ID : 0001769;
UMLS CUI : C0022077;
Automatic exact mappings (from CISMeF team)
- Iris [ICD-11 Extension code]
- Iris [ICHI extension code]
- Iris [ICHI extension code]
- Semantic type(s)
- UMLS correspondences (same concept)
- Uberon cross reference
- contributes to morphology of
- develops from
- has part
- innervated by
- part of
the adjustable membrane, composed of the stroma and pigmented epithelium, located
just in front of the crystalline lens within the eye
