Cornea - ib qho ntawm feem tseem ceeb ntawm cov tib neeg qhov muag

Ib tug ntawm cov tseem ceeb tshaj plaws qhov chaw ntawm tus tib neeg qhov muag yog lub cornea, uas tiv thaiv nws los ntawm kev puas tsuaj thiab kab mob. Txawm li cas los, thiab nws yog heev lam tau lam ua, raug rau ntau yam kab mob.

Cornea tiv thaiv pem hauv ntej feem ntawd thiab ib tug dome zoo li tus txheej nto ntawm lub qhov muag; Nws muaj tsis muaj cov hlab ntsha yuav tsum tau muab feem ntau ntawm cov tib neeg ntaub so ntswg, nws txawv kho qhov muag homogeneity. Yuav kom qualitatively refract lub teeb, lub cornea yuav tsum pob tshab, lub xub ntiag ntawm txawm heev me me hlab ntsha yuav cuam tshuam nrog txoj kev no. Lub refractive cornea ntawm lub qhov muag yog 43 diopters. Nws lub hwj chim nws tau txais mas los ntawm lub kua muag thiab aqueous lom zem nyob ntawm hauv ntej ntawm lub Chamber.

Cornea feem ntau yog muab piv rau lub khob teev, tso rau hauv ib tug ncej, txij thaum lub curvature ntawm lub cornea nws tus kheej dog dig ntau dua qhov curvature ntawm lub sclera. Cornea muaj tsib khaubncaws sab nraud povtseg, txhua muaj nws ib qho tseem ceeb muaj nuj nqi: epithelium, Descemet lub membrane, Bowman tus txheej, endothelium, stroma.

Pem hauv ntej txheej - epithelium - yog tsim los ntawm ib tug ca polygonal hlwb. Tom ntej no yog ib tug txheej ntawm Bowman - homogeneous structureless pem hauv ntej phaj ciam teb. Ua tau nws tus kheej corneal stroma yam khoom uas yog hu ua, nws yog tsim los ntawm heev nyias connective phiaj, alternating nrog txhua lwm yam uas muaj ib tug plurality ntawm kev hloov maj mam fibrils. Nyob rau hauv lub luag hauj lwm ntawm ib tug nplaum tshuaj ua mucoid muaj nyob rau hauv nws muaj pes tsawg leeg sulfogialuronovuyu acid uas muab transparency ntawm lub cornea. Lub stroma muaj tsis muaj cov hlab ntsha, thiab yog heev maj mam recovering. Descemet lub plhaub, los yog daim nyias nyias, ib tug rov qab, ib tug heev ntom, ciam teb phaj, nws fibrils muaj ib tug tshwj xeeb cov khoom siv uas yog zoo tib yam rau lub collagen; nws regenerates zoo. Lub endothelium (corneal epithelium los yog nram qab) - ib tug tuab txheej ntawm tiaj hexagonal contiguous prismatic hlwb. Cov txheej no yog lub luag hauj lwm rau cov transparency ntawm lub cornea thiab yog tsis rov qab los.

Tus qauv ntawm lub cornea yog 80% dej, 18% ntawm cov tseem collagen, hais txog 2% mucopolysaccharides, lipids, cov nqaijrog, C vitamins, B, thiab al. Koj cov neeg laus cornea muaj me npaum li cas ntawm cov vitamins thiab ya raws, nws yog yeej globulin protein fractions thiab tso calcium ntsev thiab lipids. Qhov tsim nyog ntawm cov kev hloov no yog ib tug kev hloov nyob rau hauv txoj kev hloov ntawm lub cornea (lub limbus) nyob rau hauv lub sclera - lub khaubncaws sab nraud povtseg ntawm cov sclera pib "nadvigatsya" nyob rau lub cornea thiab muaj ib tug thiaj li hu ua gerontoxon txo corneal rhiab heev thiab nws refractive lub hwj chim. Tsis tas li ntawd, nws ho txo permeability rau lub qhov muag dauv, tshuaj pleev thiab cov as-ham.

Lub rhiab heev ntawm lub cornea (innervation) trigeminal paj. Tshwj xeeb tshaj yog ib tug ntau ntawm cov hlab txoj nyob rau hauv lub ces dag khaubncaws sab nraud povtseg, lub kawg - nyob rau hauv lub endothelium. Nyob rau hauv tus me nyuam mos cov me nyuam mos, cornea yog loog vim hais tias ntawm tsis tau ua tiav txoj kev loj hlob ntawm lub cranial qab haus huv, thiab nyob rau lub hnub nyoog ntawm ib lub xyoo, nws rhiab heev yog yuav luag tib yam li nyob rau hauv cov neeg laus.

Vim lub fact tias cov cornea - lub plhaub ntawm lub qhov muag, nws yog lossi nyob rau hauv kev sib cuag nrog cov sab nraud ib puag ncig. Yog li ntawd, muaj kev tshwj xeeb mechanisms los tiv thaiv tiv thaiv cov teeb meem los ntawm sab nraud thiab kev raug mob:

1. Reflex kaw ntawm lub ob lub qhov muag;
2. Kais nrog corneal teeb meem cov neeg ua hauj los ntawm txoj kev lacrimal kua;
3. Lub ceev ceev thiab ua kom tiav rov qab los ntawm lub epithelium.

Major cov kab mob ntawm lub cornea yog: kev loj hlob txawv txav, dystrophic thiab inflammatory dab (sclerites keratitis) thiab hlav.

ob lub qhov muag keratitis los yog corneal o pathologies ntawm cov feem ntau. Keratitis yog exogenous thiab endogenous. Heev feem ntau, tom qab kev txom nyem keratitis yog clouding ntawm lub cornea ntawm qhov ntau heev. Raws li cov kev siv ntawm cov huab thiab cov nqi txawv cov huab nyob rau hauv daim ntawv ntawm cataracts, me ntsis thiab huab. Pos yog ib tug ruaj khov clouding ntawm lub cornea, uas yog vim cirrhosis, corneal occupying ib feem los yog tag nrho ntawm cov cornea. Spot - ib tug pheej khaus corneal opacity uas ntse ntse sawv nyob rau hauv lub periphery los yog nyob rau hauv lub center. Huab yog tas qhov muag plooj gray xim uas tsis yog yuav thaum lub sij hawm qhov kev xeem.