Iris yinxalenye enemibala yelihlo elilawula isixa sokukhanya esangena kwiso. Yona nxalenye ebonakalayo yiso. Iris ilele phambi kwe- crystalline lens kwaye ihlukanisa ifom yeklasi yangaphambili kwikamelo eliphezulu. Iris inxalenye yecandelo le-uveal elibandakanya umzimba we-ciliary ophinde ube ngasemva kwe-iris.
Iisisiti ze-iris zenza umfundi.
Umfundi ngumngxuma kwi-iris apho ukukhanya kudlulela khona emva kweso. Iris ilawula ubukhulu bomfundi. Umfundi ufumaneka kunye neziko lalo elincinane ngaphantsi kwaye ngokukhawuleza ukuya kwicala elisecaleni leziko le-cornea.
Size Umfundi
Ubukhulu bomfundi bulawulwa yimisipha emibili kwi-iris. I-sphincter pupillae ijikeleze umda womfundi kwaye xa iinqontrakthi, umfundi uyancipha ngobukhulu. Oku kubizwa ngokuthi i-miosis. Isisundu sesibini esilawula ubungakanani bomfundi sisi-dilator pupillae. Esi sihlunu sinezixhobo ezicwangcisiweyo kwipatheni ye-iris. Xa zivumelwano, umfundi uyancipha okanye ukhuphuke ngobukhulu. Oku kubizwa ngokuthi i-mydriasis.
Iprogram ye-parasympathetic ilawula i-sphincter pupillae kunye nesistim sevelwano silawula i-dilator pupillae. Kukho uqhagamshelo phakathi kwezi zihlunu kwinto yokuba umsila we-dilator kufuneka ukhululeke ukuze uvumele i-sphincter ukuba iminyanise umfundi.
Ubungakanani obuqhelekileyo bezinga lomfundi ukusuka ku-2 ukuya kwi-4 mm ububanzi ekukhanyeni ukuya kwi-4 ukuya kwi-8 mm emnyama.
Umbala we-Iris
Umbala we-Iris uxhomekeke kwisixa se- melanin pigment kwi-iris. Umntu onamehlo aluhlaza unombala ofanayo we-melanin pigment ukuba umntu onamehlo aluhlaza. Nangona kunjalo, umntu onamaqabunga obomvu unemibala engaphantsi.
Umqolo we-iris udla ngokugqithisa kakhulu ukukhusela ukukhanya ukukhanya nge-iris.
Iimpawu zelifa lemibala ye-iris yindawo efundela kakhulu. Umbala wamehlo ulawulwa zizifo zentlobo ezintathu ezisisiseko. Abaphengululi baqonda ezimbini zezo jeni kakuhle kwaye enye yazo isengummangaliso. Ezi jeni zilawula ukuphuhliswa kombala obomvu, obomdaka nombala ohlaza okwesibhakabhaka. I-Gray, hazel, kunye nezinye izinto ezidibanisa kunzima ukuqikelela. Kwezinye iintsapho, ilifa lembala lemibala lilandela iipateni ezinokuqikelelwa, kanti, kwezinye iindwendwe, kubonakala ingenangqiqo okanye ilandele imigaqo. Kwi-genetics, oku kuthiwa "i-polygenic". I-Polygenic ithetha ukuba kukho iindidi ezinzima ezibandakanyekayo ezibandakanyekayo ukudala umbala wamehlo. Ukutsho nje ukuba umdaka unokuba lukhulu kwizinto ezimbala okwesibhakabhaka kwenza ukuba kuchazwe lula, kodwa lo mzekelo ungelula kakhulu kuzo zonke iintlobo ezibonakalayo ebomini bokwenene.
Ukungaqhelekanga kwe-Iris noMfundi
Iris kunye neentsholongwane zabafundi zibandakanya:
- I-Aniridia - Aniridia yintsilelo yezofuzo apho umntu ezalwe khona nge-iris.
- Coloboma - I-iris coloboma yindawo enkulu kwi-iris
- I-Synechia - I-Synechia yinyameko eyenzeka phakathi kwe-lens kunye ne-iris
- I-Corectopia - iCorectopia apho apho umfundi ekhulile khona
- I-Dyscoria - iDyscoria yintlupheko apho umfundi ephosakeleyo okanye engaqhelekanga kwaye akayi kuhlaziya ngokuqhelekileyo