Ama-Platelets (thrombocytes) izingcezu ezincane ze-cytoplasm ezikhishwe ku-cytoplasm ye-Megakaryocyte evuthiwe emnkantsheni wamathambo.Nakuba i-Megakaryocyte iyinani elincane lamaseli e-hematopoietic emnkantsheni wamathambo, ebalwa kuphela u-0.05% yenani eliphelele lamaseli ane-nucleated yomnkantsha, ama-platelet awakhiqizayo abaluleke kakhulu ekusebenzeni kwe-hemostatic yomzimba.I-megakaryocyte ngayinye ingakhiqiza ama-platelet angama-200-700.
Isibalo seplatelet somuntu omdala esijwayelekile singama-150-350 × 109/L.Ama-platelet anomsebenzi wokugcina ubuqotho bezindonga zemithambo yegazi.Uma isibalo seplatelet sehla sibe ngu-50 × Uma umfutho wegazi ungaphansi kuka-109/L, ukuhlukumezeka okuncane noma ukwanda komfutho wegazi kuphela kungabangela amabala e-blood stasis esikhumbeni kanye ne-submucosa, ngisho ne-purpura enkulu.Lokhu kungenxa yokuthi ama-platelet angakwazi ukuhlala odongeni lwe-vascular nganoma yisiphi isikhathi ukuze agcwalise izikhala ezishiywe yi-endothelial cell detachment, futhi angaxubana namangqamuzana e-vascular endothelial, angase adlale indima ebalulekile ekugcineni ubuqotho be-endothelial cell noma ukulungisa amangqamuzana e-endothelial.Uma kunama-platelet ambalwa kakhulu, le misebenzi kuba nzima ukuyiqeda futhi kuba nokuthambekela kokuphuma kwegazi.Ama-platelet egazini elijikelezayo ngokuvamile asesimweni "esimile".Kodwa lapho imithambo yegazi yonakele, ama-platelet asebenza ngokuthintana komhlabathi kanye nesenzo sezici ezithile zokuhlangana.Ama-platelet acushiwe angakhulula uchungechunge lwezinto ezidingekayo kunqubo ye-hemostatic futhi asebenzise imisebenzi yomzimba efana nokunamathela, ukuhlanganisa, ukukhululwa, kanye nokukhangisa.
I-Platelet ekhiqiza i-megakaryocyte nayo itholakala kumaseli we-hematopoietic stem emnkantsheni wamathambo.Amaseli e-Hematopoietic stem aqala ukuhlukana abe amaseli e-megakaryocyte progenitor, eyaziwa nangokuthi i-colon forming unit megakaryocyte (CFU Meg).Ama-chromosome ku-nucleus yesigaba seseli yomzali ngokuvamile ama-ploidy angu-2-3.Lapho amangqamuzana okhokho eyi-diploid noma i-tetraploid, amangqamuzana anamandla okwanda, ngakho lesi yisiteji lapho imigqa yeMegakaryocyte ikhulisa inani lamaseli.Lapho amaseli e-megakaryocyte progenitor eqhubeka ehlukaniswa abe yi-8-32 ploidy Megakaryocyte, i-cytoplasm yaqala ukuhlukana futhi uhlelo lwe-Endomembrane lwaqedwa kancane kancane.Ekugcineni, i-membrane ihlukanisa i-cytoplasm yeMegakaryocyte ezindaweni eziningi ezincane.Lapho ingqamuzana ngalinye lihlukaniswa ngokuphelele, liba iplatelet.Ngalinye, ama-platelet awela e-Megakaryocyte ngegebe eliphakathi kwamangqamuzana e-endothelial odongeni lwe-sinus lomthambo futhi angena emgudwini wegazi.
Ukuba nezinto ezihluke ngokuphelele ze-immunology.I-TPO iyi-glycoprotein ekhiqizwa ikakhulukazi izinso, enesisindo samangqamuzana esingaba ngu-80000-90000.Lapho ama-platelet egazini ehla, ukugxila kwe-TPO egazini kuyanda.Imisebenzi yalesi sici esilawulayo ihlanganisa: ① ukuthuthukisa ukwakheka kwe-DNA kumaseli okhokho kanye nokwandisa inani lama-polyploid eseli;② Khuthaza i-megakaryocyte ukuze ihlanganise amaprotheni;③ Khulisa inani eliphelele le-megakaryocyte, okuholela ekwandeni kokukhiqizwa kweplatelet.Njengamanje, kukholelwa ukuthi ukwanda nokuhlukaniswa kweMegakaryocyte kulawulwa ngokuyinhloko yizici ezimbili zokulawula ezigabeni ezimbili zokuhlukanisa.Lezi zilawuli ezimbili ziyi-megakaryocyte Colony-stimulating factor (Meg CSF) ne-Thrombopoietin (TPO).I-Meg CSF iyisici esilawulayo esisebenza ngokuyinhloko esigabeni se-progenitor cell, futhi indima yayo ukulawula ukwanda kwamaseli e-megakaryocyte progenitor.Lapho inani eliphelele leMegakaryocyte kumnkantsha wethambo liyancipha, ukukhiqizwa kwalesi sici sokulawula kuyanda.
Ngemuva kokuthi ama-platelet angena egazini, anemisebenzi yomzimba kuphela ezinsukwini ezimbili zokuqala, kodwa isilinganiso sawo sokuphila singaba yizinsuku ezingu-7-14.Emisebenzini ye-physiological hemostatic, ama-platelet ngokwawo azohlakazeka futhi akhulule zonke izinto ezisebenzayo ngemva kokuhlanganisa;Ingase futhi ihlanganise namaseli e-vascular endothelial.Ngaphezu kokuguga nokubhujiswa, ama-platelet angaphinde asetshenziswe ngesikhathi sokusebenza kwawo ngokomzimba.Ama-platelet aguga agcwele izicubu ze-spleen, isibindi namaphaphu.
1. Ukwakheka kwamaplatelet
Ngaphansi kwezimo ezijwayelekile, ama-platelet avela njengama-discs e-convex kancane ezinhlangothini zombili, anobubanzi obuphakathi kuka-2-3 μ m.Ivolumu evamile yi-8 μ M3.Ama-platelet angamaseli ane-nucleated angenaso isakhiwo esithile ngaphansi kwesibonakhulu esibonakalayo, kodwa i-ultrastructure eyinkimbinkimbi ingabonwa ngaphansi kwesibonakhulu se-electron.Njengamanje, ukwakheka kwama-platelet ngokuvamile kuhlukaniswe endaweni ezungezile, indawo ye-sol gel, indawo ye-Organelle kanye nendawo yesistimu ye-membrane ekhethekile.
I-platelet surface evamile ibushelelezi, nezakhiwo ezincane ze-concave ezibonakalayo, futhi i-open canalicular system (OCS).Indawo ezungezile ye-platelet surface yakhiwe izingxenye ezintathu: ungqimba lwangaphandle, ulwelwesi lweyunithi, nendawo engaphansi kwe-submembrane.Ijazi ikakhulukazi lakhiwe ama-glycoprotein ahlukahlukene (GP), afana ne-GP Ia, i-GP Ib, i-GP IIa, i-GP IIb, i-GP IIIa, i-GP IV, i-GP V, i-GP IX, njll. Yakha izinhlobonhlobo ze-adhesion receptors futhi ingaxhuma. ku-TSP, i-thrombin, i-collagen, i-fibrinogen, njll. Kubalulekile ukuthi ama-platelet abambe iqhaza ekuhlanganiseni nasekulawuleni amasosha omzimba.I-membrane yeyunithi, eyaziwa nangokuthi i-plasma membrane, iqukethe izinhlayiya zamaprotheni ezishumekwe ku-lipid bilayer.Inombolo nokusabalalisa kwalezi zinhlayiya kuhlobene nokunamathela kweplatelet kanye nomsebenzi wokuhlangana.Ulwelwesi luqukethe i-Na+- K+- ATPase, egcina umehluko wokuhlushwa kwe-ion ngaphakathi nangaphandle kolwelwesi.I-submembrane zone itholakala phakathi kwengxenye engezansi ye-membrane yeyunithi kanye nohlangothi lwangaphandle lwe-microtubule.Indawo ye-Submembrane iqukethe imicu engaphansi kwe-submembrane kanye ne-Actin, ehlobene nokunamathela kwe-platelet nokuhlanganisa.
Ama-microtubules, ama-microfilaments kanye ne-submembrane filaments akhona futhi endaweni ye-sol gel yamaplatelet.Lezi zinto zakha uhlaka lwamathambo kanye nesistimu yokufinyela yamaplatelet, edlala indima ebalulekile ekuwohlokeni kweplatelet, ukukhululwa kwezinhlayiyana, ukwelula, kanye nokufinyela kwehlule.Ama-Microtubules akhiwa i-Tubulin, ehlanganisa i-3% yenani lamaprotheni e-platelet.Umsebenzi wabo oyinhloko ukugcina ukuma kwamaplatelet.Ama-Microfilaments ngokuyinhloko aqukethe i-Actin, okuyiprotheni eningi kakhulu kuma-platelet futhi ilandisa u-15% ~ 20% wengqikithi yamaphrotheni eplatelet.Imicu engaphansi kwe-submembrane ngokuyinhloko yizingxenye zefayibha, ezingasiza iphrotheni ebopha i-Actin kanye ne-Actin ixhumane kube izinqwaba ndawonye.Ngokwesisekelo sokuba khona kwe-Ca2+, i-actin ibambisana ne-prothrombin, i-contractin, iphrotheni ebophayo, i-co actin, i-myosin, njll.
Ithebula 1 I-Main Platelet Membrane Glycoprotein
Indawo ye-Organelle yindawo lapho kunezinhlobo eziningi ze-Organelle kuma-platelet, okunomthelela obalulekile ekusebenzeni kwamaplatelet.Futhi iyindawo yokucwaninga kwezokwelapha zesimanje.Izingxenye ezibaluleke kakhulu endaweni ye-Organelle ziyizinhlayiya ezihlukahlukene, njengezinhlayiya ezingu-α, izinhlayiya eziminyene (δ Izinhlayiya) kanye neLysosome( λ Particles, njll., bona Ithebula 1 ukuze uthole imininingwane.I-α Granules yizindawo zokugcina kuma-platelet ezingakhiqiza amaprotheni.Kukhona ngaphezu kweshumi ku-platelet ngayinye i-α Particles.Ithebula 1 libala izingxenye eziyinhloko kuphela, futhi ngokosesho lombhali, kutholwe ukuthi α Kunamazinga angaphezu kuka-230 ezinto ezitholakala kumaplatelet (PDF) akhona kumagranules.Isilinganiso sezinhlayiyana eziminyene α Izinhlayiya zincane kancane, ezinobubanzi obungu-250-300nm, futhi kunezinhlayiya eziminyene ezingu-4-8 ku-platelet ngayinye.Njengamanje, kutholwe ukuthi i-65% ye-ADP ne-ATP igcinwe ezinhlayiyeni eziminyene kuma-platelet, futhi i-90% ye-5-HT egazini iphinde igcinwe ezinhlayiyeni eziminyene.Ngakho-ke, izinhlayiya eziminyene zibalulekile ekuhlanganisweni kweplatelet.Amandla okukhulula i-ADP ne-5-HT nawo asetshenziswa emtholampilo ukuze kuhlolwe ukusebenza kweplatelet secretion.Ngaphezu kwalokho, lesi sifunda siqukethe ne-mitochondria ne-Lysosome, okuphinde kube yindawo yokucwaninga ekhaya naphesheya kulo nyaka.I-Nobel Prize in Physiology and Medicine ka-2013 yaklonyeliswa ososayensi abathathu, u-James E. Rothman, u-Randy W. Schekman, no-Thomas C. S ü dhof, ngokuthola izimfihlakalo zezindlela zokuthutha ezingaphakathi kwamangqamuzana.Kukhona nezinkambu eziningi ezingaziwa kumetabolism yezinto namandla kuma-platelet ngokusebenzisa imizimba ye-intracellular kanye ne-Lysosome.
Indawo yesistimu ye-membrane ekhethekile ihlanganisa i-OCS kanye ne-dense tubular system (DTS).I-OCS iwuhlelo lwamaphayiphi ahlukumezayo olwakhiwe ingaphezulu lama-platelet acwila phakathi kwama-platelet, okwandisa kakhulu indawo engaphezulu yama-platelet athintana ne-plasma.Ngasikhathi sinye, iwumzila ongemuhle wezinto ezahlukahlukene ukuze zingene kuma-platelet futhi zikhiphe izinhlayiya ezahlukahlukene zamaplatelet.Ipayipi le-DTS alixhunyiwe ezweni langaphandle futhi liyindawo yokuhlanganiswa kwezinto ezingaphakathi kwamaseli egazi.
2. Umsebenzi wePhysiological of Platelet
Umsebenzi oyinhloko we-physiological wamaplatelet ukubamba iqhaza ku-hemostasis kanye ne-thrombosis.Imisebenzi esebenzayo yama-platelet phakathi ne-physiological hemostasis ingahlukaniswa cishe izigaba ezimbili: i-hemostasis yokuqala kanye ne-hemostasis yesibili.Ama-platelet adlala indima ebalulekile kuzo zombili izigaba ze-hemostasis, kodwa izindlela ezithile asebenza ngazo zisahluka.
1) Umsebenzi wokuqala we-hemostatic wamaplatelet
I-thrombus eyakhiwe phakathi ne-hemostasis yokuqala ikakhulukazi i-thrombus emhlophe, futhi ukusabela okusebenzayo okufana nokunamathela kwe-platelet, ukuguqulwa, ukukhululwa, nokuhlanganisa kuyizindlela ezibalulekile enqubweni yokuqala ye-hemostasis.
I. Platelet adhesion reaction
Ukunamathela phakathi kwama-platelet kanye nezindawo ezingezona ze-platelet kubizwa ngokuthi i-platelet adhesion, okuyisinyathelo sokuqala sokubamba iqhaza ekuphenduleni okujwayelekile kwe-hemostatic ngemva kokulimala kwemithambo kanye nesinyathelo esibalulekile ku-thrombosis ye-pathological.Ngemuva kokulimala kwe-vascular, ama-platelet ageleza kulo mkhumbi asebenza ngokungaphezulu kwezicubu ezingaphansi kwe-vascular endothelium futhi ngokushesha anamathele emicu ye-collagen eveziwe endaweni yokulimala.Ngemizuzu eyi-10, ama-platelet afakwe endaweni afinyelela inani lawo eliphakeme, enza amahlule egazi amhlophe.
Izici eziyinhloko ezihilelekile enqubweni yokunamathela kweplatelet zihlanganisa i-platelet membrane glycoprotein Ⅰ (GP Ⅰ), i-von Willebrand factor (i-vW factor) kanye ne-collagen kuzicubu ze-subendothelial.Izinhlobo eziyinhloko ze-collagen ezikhona odongeni lwe-vascular ziyizinhlobo I, III, IV, V, VI, ne-VII, phakathi kwazo izinhlobo ze-collagen I, III, kanye ne-IV ezibaluleke kakhulu kwinqubo yokunamathela kweplatelet ngaphansi kwezimo ezigelezayo.I-vW factor ibhuloho elihlanganisa ukunamathela kwamaplatelet ohlotsheni lwe-collagen I, III, kanye ne-IV, futhi isamukeli esithile se-glycoprotein i-GP Ib kulwelwesi lweplatelet iyindawo eyinhloko yokubopha i-platelet collagen.Ngaphezu kwalokho, ama-glycoprotein GP IIb/IIIa, GP Ia/IIa, GP IV, CD36, ne-CD31 kulwelwesi lweplatelet nawo abambe iqhaza ekunamatheleni ku-collagen.
II.Ukusabela kokuhlanganiswa kweplatelet
Umphumela wokunamathelana kwamaplatelet komunye nomunye ubizwa ngokuthi i-aggregation.Ukusabela kokuhlanganisa kwenzeka ngokusabela kokunamathela.Lapho kukhona i-Ca2+, i-platelet membrane glycoprotein GPIIb/IIIa kanye ne-fibrinogen aggregate kuhlakaze amaplatelet ndawonye.Ukuhlanganiswa kwe-platelet kungenziwa yizinqubo ezimbili ezihlukene, enye i-inducers yamakhemikhali ehlukahlukene, kanti enye ibangelwa ukucindezeleka kwe-shear ngaphansi kwezimo ezigelezayo.Ekuqaleni kokuhlangana, ama-platelet ashintsha asuke esimweni sediski abe yindilinga futhi avele izinyawo mbumbulu ezifana nameva amancane;Ngesikhathi esifanayo, i-platelet degranulation ibhekisela ekukhishweni kwezinto ezisebenzayo ezifana ne-ADP ne-5-HT ezazigcinwe ezinhlayiyeni eziminyene.Ukukhishwa kwe-ADP, 5-HT kanye nokukhiqizwa kwe-Prostaglandin ethile kubaluleke kakhulu ekuhlanganisweni.
I-ADP iyinto ebaluleke kakhulu ekuhlanganisweni kweplatelet, ikakhulukazi i-Endogenous ADP ekhishwa kumaplatelet.Engeza inani elincane le-ADP (ukugxila ku-0.9) ekumisweni kweplatelet μ Ngezansi kwe-mol/L), kungabangela ngokushesha ukuhlanganiswa kweplatelet, kodwa ngokushesha i-depolymerize;Uma imithamo emaphakathi ye-ADP (1.0) yengezwa μ Cishe cishe i-mol/L, isigaba sesibili sokuhlanganisa esingenakuhlehliswa senzeka ngokushesha ngemva kokuphela kwesigaba sokuqala sokuhlanganisa kanye nesigaba se-depolymerization, esibangelwa i-ADP engapheli ekhishwa amaplatelet;Uma inani elikhulu le-ADP lengeziwe, libangela ngokushesha ukuhlanganisa okungenakuhlehliswa, okungena ngokuqondile esigabeni sesibili sokuhlanganisa.Ukwengeza imithamo ehlukene ye-thrombin ekumisweni kweplatelet nakho kungabangela ukuhlangana kweplatelet;Futhi ngokufana ne-ADP, njengoba umthamo ukhula kancane kancane, ukuhlanganisa okubuyisela emuva kungabonwa kusukela esigabeni sokuqala kuphela kuya ekubukeni kwezigaba ezimbili zokuhlanganisa, bese kungena ngqo esigabeni sesibili sokuhlanganisa.Ngenxa yokuthi ukuvimbela ukukhululwa kwe-ADP engapheli nge-adenosine kungavimbela ukuhlangana kweplatelet okubangelwa i-thrombin, kuphakamisa ukuthi umphumela we-thrombin ungase ubangelwe ukuboshwa kwe-thrombin kuma-thrombin receptors kulwelwesi lweplatelet cell, okuholela ekukhululweni kwe-ADP endogenous.Ukwengezwa kwe-collagen nakho kungabangela ukuhlanganiswa kweplatelet ekumisweni, kodwa ukuhlanganisa okungenakuhlehliswa kuphela esigabeni sesibili ngokuvamile okukholelwa ukuthi kubangelwa ukukhululwa kwe-ADP okubangelwa yi-collagen.Izinto ngokuvamile ezingabangela ukuhlangana kwe-platelet zinganciphisa i-cAMP kuma-platelet, kuyilapho lezo ezivimbela ukuhlangana kwe-platelet zandisa i-cAMP.Ngakho-ke, okwamanje kukholakala ukuthi ukuncipha kwe-cAMP kungase kubangele ukwanda kwe-Ca2+ kumaplatelet, kukhuthaze ukukhululwa kwe-ADP engapheli.I-ADP idala ukuhlanganiswa kweplatelet, okudinga ukuba khona kwe-Ca2+ ne-fibrinogen, kanye nokusetshenziswa kwamandla.
Indima yePletelet Prostaglandin I-phospholipid ye-platelet plasma membrane iqukethe i-Arachidonic acid, kanti i-platelet cell iqukethe i-Phosphatidic acid A2.Lapho ama-platelet esebenza phezulu, i-Phospholipase A2 nayo iyasebenza.Ngaphansi kwe-catalysis ye-Phospholipase A2, i-arachidonic acid ihlukaniswa nama-phospholipids kulwelwesi lwe-plasma.I-Arachidonic acid ingakha inani elikhulu le-TXA2 ngaphansi kwe-catalysis ye-platelet cyclooxygenase ne-Thromboxane synthase.I-TXA2 yehlisa i-cAMP kumaplatelet, okuholela ekuhlanganisweni okuqinile kweplatelet kanye nomphumela we-vasoconstriction.I-TXA2 nayo ayizinzile, ngakho ishintsha ngokushesha ibe i-TXB2 engasebenzi.Ngaphezu kwalokho, amangqamuzana avamile e-vascular endothelial aqukethe i-prostacyclin synthase, engabangela ukukhiqizwa kwe-prostacyclin (PGI2) kumaplatelet.I-PGI2 ingakhuphula i-cAMP kuma-platelet, ngakho-ke inomphumela oqinile wokuvinjelwa kwe-platelet aggregation kanye ne-Vasoconstriction.
I-Adrenaline ingadlulela ku-α 2. Ukulamula kwe-Adrenergic receptor kungabangela ukuhlanganiswa kweplatelet ye-biphasic, ngokugxila kwe-(0.1~10) μ Mol/L.I-Thrombin ekugxilweni okuphansi (<0.1 μ Ku-mol/L, isigaba sokuqala sokuhlanganisa amaplatelet sibangelwa ikakhulukazi i-PAR1; Ekugxilweni okuphezulu (0.1-0.3) μ Ku-mol/L, ukuhlanganisa kwesigaba sesibili kungenziwa yi-PAR1 ne-PAR4 . Ama-inducer aqinile wokuhlangana kwe-platelet aphinde ahlanganise i-platelet activating factor (PAF), i-collagen, i-vW factor, i-5-HT, njll. Ukuhlanganiswa kwe-Platelet kungase futhi kwenziwe ngokuqondile isenzo somshini ngaphandle kwanoma iyiphi i-inducer. Lo mshini usebenza ngokuyinhloko ku-arterial thrombosis, njenge i-atherosclerosis.
III.Ukusabela kokukhishwa kweplatelet
Lapho ama-platelet engaphansi kokukhuthazwa komzimba, agcinwa ezinhlayiyeni eziminyene α Isenzakalo sezinto eziningi ezinhlayiyeni nama-lysosomes akhishwa kumaseli kubizwa ngokuthi ukusabela kokukhululwa.Umsebenzi wamaplatelet amaningi ufezwa ngemiphumela yezinto eziphilayo ezakhiwe noma ezikhishwe ngesikhathi sokusabela kokukhululwa.Cishe wonke ama-inducers abangela ukuhlangana kweplatelet angabangela ukusabela kokukhululwa.Ukusabela kokukhululwa ngokuvamile kwenzeka ngemva kokuhlanganisa kwesigaba sokuqala samaplatelet, futhi into ekhishwa ukusabela kokukhululwa idala ukuhlanganisa kwesigaba sesibili.Ama-inducers abangela ukusabela kokukhululwa angahlukaniswa cishe abe:
i.Inducer ebuthakathaka: I-ADP, i-adrenaline, i-Norepinephrine, i-vasopressin, i-5-HT.
ii.Ama-inducers amaphakathi: TXA2, PAF.
iii.Ama-inducers anamandla: i-thrombin, i-pancreatic enzyme, i-collagen.
2) Indima yama-platelet ekuhlanganiseni kwegazi
Ama-platelet ikakhulukazi abamba iqhaza ekuphenduleni okuhlukahlukene kwe-coagulation ngokusebenzisa ama-phospholipids kanye ne-membrane glycoprotein, okuhlanganisa i-adsorption kanye nokwenza kusebenze izici ze-coagulation (izici IX, XI, kanye ne-XII), ukwakheka kokuhlangana okugqugquzela ama-complexes ebusweni be-phospholipid membranes, kanye nokukhuthaza ukwakheka kwe-prothrombin.
Ulwelwesi lwe-plasma olungaphezulu kwama-platelet lubopha izici ezihlukahlukene zokuhlangana, njenge-fibrinogen, i-factor V, i-factor XI, i-factor XIII, njll. kanye ne-PF3 zombili zikhuthaza ukujiya kwegazi.I-PF4 inganciphisa i-heparin, kuyilapho i-PF6 ivimbela i-fibrinolysis.Lapho ama-platelet esebenza phezulu, angasheshisa inqubo yokwenza kusebenze indawo yezici ze-coagulation XII ne-XI.I-phospholipid surface (PF3) ehlinzekwa ngamaplatelet ilinganiselwa ukuthi isheshisa ukusebenza kwe-prothrombin izikhathi ezingu-20000.Ngemva kokuxhuma izici i-Xa no-V ebusweni bale phospholipid, zingaphinde zivikeleke emiphumeleni evimbelayo ye-antithrombin III ne-heparin.
Lapho ama-platelet ehlangana ukuze enze i-hemostatic thrombus, inqubo yokuhlanganisa isivele yenzekile endaweni, futhi ama-platelet aveze inani elikhulu lezindawo ze-phospholipid, okuhlinzeka ngezimo ezivumayo kakhulu zokusebenzisa i-factor X ne-prothrombin.Lapho ama-platelet ekhuthazwa yi-collagen, i-thrombin noma i-kaolin, i-Sphingomyelin ne-Phosphatidylcholine engaphandle kolwelwesi lwe-platelet ziphenduka ne-phosphatidyl Ethanolamine ne-phosphatidylserine ngaphakathi, okuholela ekwandeni kwe-phosphatidyl Ethanolamine ne-membrane phosphatidyl ebusweni bobuso.Amaqembu e-phosphatidyl angenhla aphendukile phezu kwamaplatelet abamba iqhaza ekwakhiweni kwama-vesicle ebusweni be-membrane ngesikhathi sokusebenza kweplatelet.Ama-vesicles ayahlakazeka futhi angena ekujikelezeni kwegazi ukuze akhe ama-microcapsules.Ama-vesicles nama-microcapsules acebile ku-phosphatidylserine, esiza ekuhlanganiseni nasekusebenzeni kwe-prothrombin futhi abambe iqhaza ohlelweni lokukhuthaza ukuhlangana kwegazi.
Ngemuva kokuhlanganiswa kweplatelet, i-α yayo Ukukhululwa kwezici ezihlukahlukene ze-platelet ezinhlayiyeni kukhuthaza ukwakheka nokwanda kwemicu yegazi, futhi kubamba amanye amangqamuzana egazi ukuze enze amahlule.Ngakho-ke, nakuba ama-platelet ehlukana kancane kancane, i-hemostatic emboli isengakhula.Ama-platelet asele ehlule legazi ane-pseudopodia engena kunethiwekhi ye-fiber yegazi.Amaprotheni enkontileka kulawa ma-platelet ayafinyela, abangele ukujiya kwegazi kuhlehle, akhiphe i-serum futhi abe ipulaki eliqinile le-hemostatic, elivala ngokuqinile igebe lemithambo.
Lapho kusebenze ama-platelet kanye nesistimu yokuhlangana phezulu, iphinde isebenze uhlelo lwe-fibrinolytic.I-Plasmin kanye ne-activator yayo equkethwe kuma-platelet izokhishwa.Ukukhululwa kwe-serotonin emicu yegazi namaplatelet nakho kungabangela amangqamuzana e-endothelial ukuthi akhulule ama-activators.Kodwa-ke, ngenxa yokuhlakazeka kwamaplatelet kanye nokukhululwa kwe-PF6 nezinye izinto ezivimbela ama-protease, azithintwa umsebenzi we-fibrinolytic ngesikhathi sokwakhiwa kwamahlule egazi.
(Okuqukethwe yile ndatshana kuphrintwe kabusha, futhi asinikezeli nganoma yisiphi isiqinisekiso esicacile noma esishiwoyo sokunemba, ukwethembeka noma ukuphelela kokuqukethwe okuqukethwe kulesi sihloko, futhi asinasibopho ngemibono yalesi sihloko, sicela uqonde.)
Isikhathi sokuthumela: Jun-13-2023