Kev sib txuas ntawm cov hlwb uas muaj nyob rau hauv cov ntaub so ntswg thiab cov kabmob ntawm cov kabmob multicellular yog tsim los ntawm cov txheej txheem nyuaj hu ua intercellular hu. Tshwj xeeb tshaj yog lawv pom nyob rau hauv lub epithelium, ciam teb integumentary txheej.
Cov kws tshawb fawb ntseeg tias thawj qhov kev sib cais ntawm cov txheej txheem sib cuam tshuam los ntawm kev sib cuag ntawm tes ua kom muaj kev tsim thiab kev loj hlob ntawm cov kabmob thiab cov ntaub so ntswg.
Ua tsaug rau kev siv cov txheej txheem electron microscopy, nws muaj peev xwm khaws tau ntau cov ntaub ntawv hais txog ultrastructure ntawm cov nyiaj no. Txawm li cas los xij, lawv cov biochemical muaj pes tsawg leeg, nrog rau lawv cov qauv molecular, tsis tau kawm txaus hnub no.
Tom ntej, xav txog cov yam ntxwv, pab pawg thiab hom kev sib cuag ntawm tes.
cov ntaub ntawv dav dav
Cov daim nyias nyias muaj kev koom tes hauv kev tsim cov neeg sib cuag. Nyob rau hauv multicellular kab mob, vim yog kev sib cuam tshuam ntawm cov ntsiab lus, complex cellular formations yog tsim. Lawv khaws ciatuaj yeem muab tau rau ntau txoj hauv kev.
Nyob rau hauv embryonic, kab mob cov ntaub so ntswg, tshwj xeeb tshaj yog nyob rau hauv thawj theem ntawm txoj kev loj hlob, hlwb tswj kev sib raug zoo nrog ib leeg vim qhov tseeb hais tias lawv nto muaj peev xwm los ua ke. Xws li adhesion (kev sib txuas) yuav cuam tshuam nrog cov khoom nto ntawm cov khoom.
Specific tsos
Cov kws tshawb fawb ntseeg tias kev tsim cov kev sib cuag ntawm tes yog muab los ntawm kev sib cuam tshuam ntawm glycocalyx nrog lipoproteins. Thaum sib txuas, qhov sib txawv me me ib txwm nyob (nws qhov dav yog li 20 nm). Nws muaj glycocalyx. Thaum cov ntaub so ntswg raug kho nrog ib qho enzyme uas tuaj yeem cuam tshuam nws txoj kev ncaj ncees lossis ua rau lub cev puas tsuaj, cov hlwb pib sib cais thiab sib cais.
Yog tias qhov cuam tshuam raug tshem tawm, cov hlwb tuaj yeem rov ua dua. Qhov tshwm sim no hu ua reaggregation. Yog li koj tuaj yeem cais cov hlwb ntawm daim txhuam cev ntawm cov xim sib txawv: daj thiab txiv kab ntxwv. Thaum qhov kev sim, nws tau pom tias tsuas yog 2 hom kev sib sau ua ke tshwm sim hauv kev sib txuas ntawm cov hlwb. Qee tus tsuas yog txiv kab ntxwv xwb, thaum lwm tus tsuas yog cov qe daj xwb. Mixed suspensions, nyob rau hauv lem, nws tus kheej-organize thiab restore lub thawj multicellular qauv.
Cov txiaj ntsig zoo sib xws tau txais los ntawm cov kws tshawb fawb hauv kev sim nrog kev ncua ntawm cov kab mob amphibian embryonic sib cais. Hauv qhov no, cov hlwb ntawm ectoderm cais hauv qhov chaw xaiv los ntawm mesenchyme thiab endoderm. Yog tias peb siv cov ntaub tom qabCov theem ntawm kev loj hlob ntawm cov embryos, cov pab pawg ntawm tes sib txawv nyob rau hauv lub cev thiab cov ntaub so ntswg tshwj xeeb yuav nws tus kheej sib sau ua ke nyob rau hauv lub xeem tube, epithelial aggregates yuav tsim, zoo li lub raum tubules.
Physiology: hom kev sib cuag ntawm tes
Cov kws tshawb fawb paub qhov txawv ntawm 2 pawg tseem ceeb ntawm kev sib txuas:
- Yooj yim. Lawv tuaj yeem tsim cov tebchaw uas txawv ntawm cov duab.
- Txhob. Cov no suav nrog slit-zoo li, desmosomal, nruj intercellular junctions, nrog rau cov nplaum nplaum thiab synapses.
Cia peb saib lawv cov yam ntxwv luv luv.
kev sib hlub yooj yim
Yooj yim intercellular junctions yog qhov chaw ntawm kev sib cuam tshuam ntawm supramembrane cellular complexes ntawm plasmolemma. Qhov kev ncua deb ntawm lawv yog tsis ntau tshaj 15 nm. Intercellular hu muab adhesion ntawm cov ntsiab lus vim kev sib nrig sib "paub". Lub glycocalyx yog nruab nrog tshwj xeeb receptor complexes. Lawv yog cov nruj nruj rau txhua tus neeg lub cev.
Kev tsim cov receptor complexes yog tshwj xeeb hauv cov neeg ntawm cov hlwb lossis qee cov ntaub so ntswg. Lawv sawv cev los ntawm integrins thiab cadherins, uas muaj affinity rau cov qauv zoo sib xws ntawm cov hlwb nyob sib ze. Thaum muaj kev cuam tshuam nrog cov molecules nyob rau ntawm cytomembranes uas nyob ib sab, lawv lo ua ke - adhesion.
Intercellular hu rau hauv histology
Ntawm cov nplaum nplaum yog:
- Integrins.
- Selectins.
- Cadherins.
Immunoglobulins.
Qee cov nplaum nplaum tsis muaj nyob hauv ib tsev neeg no.
yam ntxwv ntawm tsev neeg
Qee glycoproteins ntawm lub xov tooj ntawm tes apparatus yog rau lub ntsiab histocompatibility complex ntawm chav kawm 1. Zoo li integrins, lawv yog cov tib neeg nruj me ntsis rau ib tus neeg lub cev thiab tshwj xeeb rau cov ntaub so ntswg uas lawv nyob. Qee cov tshuaj muaj nyob hauv qee cov ntaub so ntswg. Piv txwv li, E-cadherins yog tshwj xeeb rau cov epithelium.
Integrins yog hu ua ib qho proteins, uas muaj 2 subunits - alpha thiab beta. Tam sim no, 10 qhov sib txawv ntawm thawj thiab 15 hom thib ob tau txheeb xyuas. Intracellular thaj tsam khi rau nyias microfilaments siv cov protein tshwj xeeb molecules (tannin lossis vinculin) lossis ncaj qha rau actin.
Selectins yog cov proteins monomeric. Lawv paub txog qee yam carbohydrate complexes thiab txuas rau lawv ntawm lub xov tooj ntawm tes. Tam sim no, feem ntau kawm yog L, P thiab E-selectins.
Immunoglobulin-zoo li cov nplaum nplaum proteins yog cov qauv zoo ib yam li cov tshuaj tiv thaiv classical. Qee tus ntawm lawv yog cov receptors rau cov tshuaj tiv thaiv kab mob, lwm tus tsuas yog npaj rau kev ua haujlwm ntawm cov nplaum nplaum.
Intercellular hu ntawm cadherins tshwm sim tsuas yog nyob rau hauv lub xub ntiag ntawm calcium ions. Lawv koom nrog hauv kev tsim cov ntawv cog lus ruaj khov: P thiab E-cadherins hauv cov ntaub so ntswg epithelial, thiab N-cadherins- nyob rau hauv cov leeg nqaij thiab tshee.
Destination
Nws yuav tsum tau hais tias kev sib cuag ntawm tes tsis yog tsuas yog rau kev ua kom yooj yim ntawm cov ntsiab lus. Lawv yog ib qho tsim nyog los xyuas kom meej lub cev ua haujlwm ntawm cov ntaub so ntswg thiab cov hlwb, hauv kev tsim cov uas lawv koom nrog. Kev sib cuag yooj yim tswj qhov kev loj hlob thiab kev txav ntawm cov hlwb, tiv thaiv hyperplasia (nce ntau dhau ntawm cov qauv tsim).
Ntau yam sib xyaws
Nyob rau hauv cov chav kawm ntawm kev tshawb fawb, ntau hom intercellular hu tau tsim. Lawv tuaj yeem ua tau, piv txwv li, hauv daim ntawv ntawm "vuas". Xws li kev sib txuas yog tsim nyob rau hauv stratum corneum ntawm stratified keratinized epithelium, nyob rau hauv cov hlab ntsha endothelium. Kuj tseem muaj serrated thiab ntiv tes-puab hom. Nyob rau hauv thawj zaug, lub protrusion ntawm ib lub ntsiab dab dej rau hauv lub concave ib feem ntawm lwm yam. Qhov no ua rau kom muaj zog txhua yam ntawm kev sib koom ua ke.
kev sib txuas nyuaj
Cov hom kev sib cuag ntawm tes no yog tshwj xeeb rau kev ua haujlwm ntawm ib qho haujlwm tshwj xeeb. Cov tebchaw zoo li no tau sawv cev los ntawm cov khoom tshwj xeeb me me ntawm cov plasma daim nyias nyias ntawm 2 lub hlwb nyob sib ze.
Muaj ntau hom kev sib txuas hauv qab no:
- Kaws.
- Hooks.
- kev sib txuas lus.
Desmosomes
Lawv yog cov txheej txheem macromolecular nyuaj, dhau los ntawm kev sib txuas zoo ntawm cov khoom nyob sib ze tau lees paub. Nrog electron microscopy, hom kev sib cuag no pom tau zoo heev, vim nws txawv los ntawm cov khoom siv hluav taws xob siab. Cov cheeb tsam hauv zos zoo li lub disk. Nws txoj kab uas hla yog li 0.5 µm. Cov membranes ntawm cov nyob sib ze nyob rau hauv nws nyob ntawm qhov deb ntawm 30 mus rau 40 nm.
Koj tseem tuaj yeem xav txog thaj chaw ntawm cov hluav taws xob siab ceev ntawm sab hauv daim nyias nyias ntawm ob lub hlwb sib cuam tshuam. Intermediate filaments txuas rau lawv. Nyob rau hauv cov ntaub so ntswg epithelial, cov ntsiab lus no yog sawv cev los ntawm tonofilaments, uas tsim pawg - tonofibrils. Tonofilaments muaj cytokeratins. Ib thaj tsam electron-dense kuj pom nyob nruab nrab ntawm cov daim nyias nyias, uas sib haum mus rau adhesion ntawm cov protein complexes ntawm cov cellular nyob sib ze.
Raws li txoj cai, desmosomes pom nyob rau hauv cov ntaub so ntswg epithelial, tab sis lawv tuaj yeem kuaj pom hauv lwm cov qauv thiab. Nyob rau hauv cov ntaub ntawv no, intermediate filaments muaj cov yam ntxwv ntawm cov ntaub so ntswg. Piv txwv li, muaj vimentins hauv cov qauv sib txuas, desmins hauv cov leeg, thiab lwm yam.
Sab hauv ntawm desmosome ntawm qib macromolecular yog sawv cev los ntawm desmoplakins - txhawb cov proteins. Intermediate filaments txuas nrog lawv. Desmoplakins, nyob rau hauv lem, yog txuas mus rau desmogleins los ntawm placoglobins. Qhov no triple compound kis los ntawm lipid txheej. Desmogleins khi rau cov proteins hauv cov cell uas nyob sib ze.
Txawm li cas los xij, lwm txoj kev xaiv kuj ua tau. Kev sib txuas ntawm desmoplakins yog nqa tawm rau cov proteins uas nyob hauv daim nyias nyias - desmocolins. Cov no, dhau los, khi rau cov proteins zoo sib xws hauv cytomembrane uas nyob ib sab.
Nws kuj tau nthuav tawm raws li kev sib txuas tshuab. Txawm li cas los xij, nws qhov tshwj xeeb yog daim ntawv. Txoj siv desmosome zoo li ribbon. Zoo li lub npoo, cov tuav tuav qhwv ib ncig ntawm cytolemma thiab cov cell membranes uas nyob ib sab.
Qhov kev sib cuag no yog tus yam ntxwv los ntawm cov hluav taws xob siab ceev ob qho tib si hauv thaj tsam ntawm daim nyias nyias thiab hauv thaj chaw uas muaj cov tshuaj intercellular nyob.
Vinculin tam sim no nyob rau hauv txoj siv clutch, ib qho kev txhawb nqa protein uas ua raws li qhov chaw txuas rau microfilaments rau sab hauv ntawm cytomembrane.
Daim kab xev nplaum tuaj yeem pom nyob rau hauv ntu apical ntawm ib txheej txheej epithelium. Nws feem ntau nyob ib sab ntawm kev sib cuag nruj. Ib tug txawv feature ntawm no compound yog hais tias nws cov qauv muaj xws li actin microfilaments. Lawv yog parallel rau ntawm daim nyias nyias. Vim lawv muaj peev xwm cog lus nyob rau hauv lub xub ntiag ntawm minimyosins thiab instability, tag nrho cov txheej ntawm epithelial hlwb, nrog rau cov microrelief ntawm lub cev uas lawv kab, yuav hloov lawv cov duab.
Gap contact
Nws tseem hu ua kev sib txuas. Raws li txoj cai, endotheliocytes txuas nrog txoj kev no. Intercellular junctions ntawm qhov zoo li hom yog disk-puab. Nws qhov ntev yog 0.5-3 microns.
Ntawm qhov chaw sib txuas, cov kab uas nyob ib sab nyob ntawm qhov deb ntawm 2-4 nm ntawm ib leeg. Integral proteins, connectins, muaj nyob rau saum npoo ntawm ob lub ntsiab lus. Lawv, nyob rau hauv lem, tau koom ua ke rau hauv connexons - protein complexes muaj 6 molecules.
Connexon complexes yog nyob ib sab. Hauv nruab nrab ntawm txhua tus muaj qhov pore. Cov ntsiab lus uas nws qhov hnyav molecular tsis tshaj 2 txhiab tuaj yeem dhau los ntawm nws. Vim li no, cov molecules ntawm inorganic ions, dej, monomers, low-molecular biologically active tshuaj txav mus rau lub cell nyob sib ze, thiab lawv tsis nkag mus rau hauv lub intercellular tshuaj.
Nexus nta
Vim qhov kev sib cuag zoo li qhov sib txuas, kev zoo siab tau xa mus rau cov khoom nyob sib ze. Piv txwv li, qhov no yog li cas impulses kis ntawm neurons, du myocytes, cardiomyocytes, thiab lwm yam. Vim yog nexuses, kev sib sau ntawm cell bioreactions nyob rau hauv cov ntaub so ntswg yog guaranteed. Hauv cov txheej txheem neural, qhov sib txawv ntawm qhov sib txuas yog hu ua hluav taws xob synapses.
Cov dej num ntawm nexuses yog tsim kom muaj kev sib cuam tshuam ntawm kev tswj hwm ntawm tes bioactivity. Tsis tas li ntawd, cov kev sib cuag no ua tau ntau yam haujlwm tshwj xeeb. Piv txwv li, yog tias tsis muaj lawv yuav tsis muaj kev sib koom ua ke ntawm kev cog lus ntawm lub plawv cardiomyocytes, synchronous tshua ntawm cov leeg nqaij, thiab lwm yam.
Tight contact
Nws tseem hu ua thaj chaw xauv. Nws yog nthuav tawm raws li qhov chaw ntawm fusion ntawm daim tawv nqaij txheej txheej ntawm cov hlwb nyob sib ze. Cov cheeb tsam no tsim ib lub network txuas ntxiv, uas yog "crosslinked" los ntawm cov protein molecules ntawm cov membranes ntawm cov cellular nyob sib ze. Cov proteins no tsim cov qauv zoo li mesh. Nws ncig lub perimeter ntawm lub cell nyob rau hauv daim ntawv ntawm ib tug siv. Nyob rau hauv cov ntaub ntawv no, tus qauv txuas rau qhov chaw nyob ib sab.
Ntse kom nruj kev sib cuagnyob sib ze banded desmosomes. Qhov chaw no yog impermeable rau ions thiab molecules. Yog li ntawd, nws kaw qhov sib txawv ntawm intercellular thiab, qhov tseeb, ib puag ncig sab hauv ntawm tag nrho cov kab mob los ntawm lwm yam.
Meaning of thaiv tsam
Kev sib cuag nruj tiv thaiv kev sib kis ntawm cov tebchaw. Piv txwv li, cov ntsiab lus ntawm lub plab kab noj hniav yog kev tiv thaiv los ntawm ib puag ncig sab hauv ntawm nws cov phab ntsa, cov protein complexes tsis tuaj yeem txav los ntawm cov dawb epithelial nto mus rau qhov chaw intercellular, thiab lwm yam. Qhov chaw thaiv kuj tseem txhawb nqa cell polarization.
Kev sib tw nruj yog lub hauv paus ntawm ntau yam teeb meem tam sim no hauv lub cev. Nyob rau hauv lub xub ntiag ntawm thaiv cov cheeb tsam, kev hloov ntawm cov tshuaj mus rau cov nyob ib puag ncig ib puag ncig yog nqa tawm tsuas yog los ntawm lub cell.
Synapses
Lawv yog cov chaw tshwj xeeb nyob hauv cov neurons (paj hlwb). Vim lawv, cov ntaub ntawv kis tau los ntawm ib lub xov tooj mus rau lwm qhov.
Ib qho kev sib txuas synaptic muaj nyob rau hauv cov chaw tshwj xeeb thiab nruab nrab ntawm ob lub paj hlwb, thiab nruab nrab ntawm cov neuron thiab lwm lub ntsiab lus suav nrog hauv effector lossis receptor. Piv txwv li, neuro-epithelial, neuromuscular synapses yog cais.
Cov kev sib cuag no tau muab faib ua hluav taws xob thiab tshuaj lom neeg. Cov qub zoo ib yam li gap bonds.
Intercellular substance adhesion
Cells txuas los ntawm cytolemmal receptors rau cov nplaum proteins. Piv txwv li, receptors rau fibronectin thiab laminin nyob rau hauv epithelial hlwb muab adhesion rau cov no.glycoproteins. Laminin thiab fibronectin yog adhesive substrates nrog lub fibrillar lub hauv paus daim nyias nyias (hom IV collagen fibers).
Hemidesmosome
Los ntawm sab ntawm tes, nws cov biochemical muaj pes tsawg leeg thiab cov qauv zoo ib yam li cov dismosome. Tshwj xeeb thauj tog rau nkoj filaments txuas ntawm lub cell mus rau hauv cov khoom intercellular. Vim lawv, daim nyias nyias tau ua ke nrog cov txheej txheem fibrillar thiab anchoring fibrils ntawm hom VII collagen fibers.
Point contact
Nws tseem hu ua focal. Point contact yog suav nrog hauv pab pawg ntawm kev sib txuas sib txuas. Nws yog suav hais tias yog feem ntau yam ntxwv ntawm fibroblasts. Nyob rau hauv cov ntaub ntawv no, lub cell tsis ua raws li cov nyob sib ze cellular ntsiab, tab sis rau intercellular lug. Receptor proteins cuam tshuam nrog cov nplaum molecules. Cov no muaj xws li chondronectin, fibronectin, thiab lwm yam. Lawv khi cell membranes rau extracellular fibers.
Tsim kom muaj qhov chaw tiv tauj yog ua los ntawm actin microfilaments. Lawv raug kho rau sab hauv ntawm cytolemma nrog kev pab ntawm cov proteins ib txwm.
