Cov Qauv thiab Kev Ua Haujlwm ntawm Platelets
Cov platelets, lossis cov platelets ntshav, yog cov cell me me uas pom muaj nyob rau hauv cov ntshav thiab koom nrog cov txheej txheem ntshav txhaws (hemostasis). Lawv yog ib feem tseem ceeb ntawm tib neeg lub cev ncig ntshav, ua lub luag haujlwm tseem ceeb hauv kev tiv thaiv kev los ntshav thiab pib kho qhov txhab. Hauv tsab xov xwm no, peb yuav tshawb nrhiav qhov sib txawv ntawm cov qauv thiab kev ua haujlwm ntawm cov platelets, nrog rau lawv qhov tseem ceeb hauv kev tswj hwm kev noj qab haus huv ntawm lub cev.
Keeb Kwm thiab Kev Tsim Khoom ntawm Platelets
Cov platelets pib los ntawm cov hlwb loj hu ua megakaryocytes hauv cov pob txha pob txha. Megakaryocytes yog cov hlwb loj heev thiab nyuaj heev, nrog rau txoj kab uas hla mus txog 100 micrometers. Cov hlwb no tsim cov platelets los ntawm kev tso cov khoom me me ntawm lawv cov cytoplasm mus rau hauv cov ntshav. Cov txheej txheem no raug tswj hwm los ntawm ntau yam kev loj hlob thiab cov tshuaj hormones, suav nrog thrombopoietin, uas ua rau megakaryocyte tsim thiab loj hlob.
Thaum twg tsim tau lawm, cov ntshav platelets yuav ncig mus rau hauv cov ntshav li ntawm 7 txog 10 hnub ua ntej raug rhuav tshem los ntawm lub cev reticuloendothelial, feem ntau yog nyob rau hauv lub po thiab lub siab. Feem ntau, cov ntshav platelets hauv cov ntshav yog txij li 150.000 txog 450.000 ib microliter. Cov ntshav platelets tsawg hu ua thrombocytopenia, thaum cov ntshav platelets ntau hu ua thrombocytosis.
Cov qauv ntawm cov ntshav platelet
Txawm hais tias cov platelets me me xwb los, lawv muaj cov qauv tshwj xeeb thiab nyuaj heev, uas ntsuas ntawm 2 thiab 3 micrometers hauv txoj kab uas hla. Lawv cov qauv muaj ntau yam tseem ceeb:
1. Daim nyias nyias ntawm cov ntshav: Txheej sab nraud ntawm cov ntshav platelets, uas muaj cov receptors rau ntau yam signaling molecules, suav nrog collagen, fibrinogen, thiab cov growth factors. Daim nyias nyias no kuj txhawb nqa glycoproteins uas ua lub luag haujlwm tseem ceeb hauv kev sib sau ua ke ntawm cov ntshav platelet thiab kev lo rau cov phab ntsa ntawm cov hlab ntsha raug mob.
2. Cytoplasm: Sab hauv ntawm cov platelet uas muaj ntau yam organelles thiab cov qauv, suav nrog mitochondria, lysosomes, thiab granules. Cov granules no muaj cov alpha granules, uas muaj cov protein coagulation xws li fibrinogen thiab cov growth factors, thiab dens granules, uas muaj cov molecules xws li ADP thiab calcium uas ua lub luag haujlwm hauv platelet activation.
3. Cytoskeleton: Ib lub network ntawm cov protein hauv cov platelets uas muab cov duab thiab kev txhawb nqa. Cov ntsiab lus tseem ceeb ntawm cov cytoskeleton no suav nrog actin thiab microtubules, uas tso cai rau cov platelets hloov lawv cov duab thaum lub sijhawm ua haujlwm thiab sib sau ua ke.
4. Lub Tshuab Qhib Channel thiab Lub Tshuab Dense Tubular: Cov qauv membrane sab hauv uas ua haujlwm hauv kev khaws cia thiab tso tawm cov signaling molecules. Lub tshuab qhib channel sib txuas lus nrog sab nraud ntawm lub cell thiab pab tso tawm cov granule contents, thaum lub tshuab dense tubule ua lub luag haujlwm hauv kev khaws cia calcium thiab kev tswj cov calcium hauv lub cell.
Kev Ua Haujlwm ntawm Platelet
Cov platelets muaj ntau lub luag haujlwm tseem ceeb ntsig txog hemostasis thiab kho qhov txhab:
1. Kev Tsim Cov Platelet Plug
Thaum cov hlab ntsha raug mob, collagen thiab cov nqaij ntawm cov extracellular matrix uas raug nthuav tawm tam sim ntawd ua rau cov platelets ua haujlwm. Cov platelets uas tau ua haujlwm hloov pauv cov duab, ua nplaum dua, thiab lo rau ntawm phab ntsa hlab ntsha raug mob. Lawv kuj pib tso cov ntsiab lus ntawm lawv cov granules, suav nrog cov coagulation factors thiab lwm yam signaling molecules uas nyiam cov platelets ntau dua rau qhov chaw raug mob.
Cov txheej txheem no ua rau muaj cov platelet plug thawj zaug uas yuav tsum tsis txhob los ntshav ib ntus. Qhov no yog thawj kauj ruam hauv kev hemostasis thawj zaug, uas tiv thaiv kev poob ntshav ntau dhau kom txog thaum cov txheej txheem coagulation thib ob tuaj yeem tsim cov ntshav khov kho dua.
2. Kev Tso Tawm Cov Tshuaj Lom Neeg Sib Tham
Thaum ua haujlwm, cov platelets tso tawm ntau yam tshuaj mediators los ntawm lawv cov granules. Alpha granules tso tawm cov protein xws li fibrinogen, platelet growth factor (PDGF), coagulation factors, kininogen, thiab vWf (von Willebrand factor), uas pab txhawb rau platelet aggregation thiab platelet plug stabilization. Dens granules tso tawm cov molecules me me xws li ADP, ATP, serotonin, thiab calcium, uas ua lub luag haujlwm hauv vasoconstriction, ntxiv nyiam ntau platelets mus rau qhov chaw raug mob, thiab ntxiv platelet activation.
Piv txwv li, ADP khi rau P2Y12 receptor ntawm qhov chaw ntawm cov ntshav platelet, ua rau cov ntshav platelet hloov pauv, ua rau lawv muaj kev sib raug zoo rau fibrinogen, thiab ua kom muaj kev sib cuam tshuam ntawm cov ntshav platelets, ua rau muaj kev sib sau ua ke zoo dua. Calcium ua lub luag haujlwm tseem ceeb hauv ntau kauj ruam ntawm kev coagulation, pab tsim cov enzymatic complexes ntawm qhov chaw ntawm cov ntshav platelet.
3. Kev sib xyaw ua ke thiab kev tsim cov fibrin
Ntxiv rau qhov tsim cov platelet plug thiab tso cov mediators, platelets kuj txhawb nqa kev tsim cov fibrin, ib qho protein uas ua rau lub platelet plug muaj zog thiab ruaj khov. Cov platelets uas tau qhib ua rau muaj ib qho chaw uas pab txhawb kev sib cuam tshuam ntawm cov coagulation factors hauv txoj kev intrinsic thiab extrinsic, thaum kawg ua rau kev hloov pauv ntawm soluble fibrinogen mus rau insoluble fibrin. Fibrin ces tsim ib lub network uas ntes cov qe ntshav liab thiab lwm cov qe ntshav hauv cov ntshav, tsim cov ntshav khov kho.
4. Kev Kho Mob Qhov Mob
Ntxiv rau lawv lub luag haujlwm hauv hemostasis, platelets kuj pab txhawb rau cov txheej txheem kho qhov txhab. Cov yam ntxwv loj hlob uas platelets tso tawm, xws li PDGF, vascular endothelial growth factor (VEGF), thiab transforming growth factor-beta (TGF-β), txhawb kev loj hlob thiab kev tsiv teb tsaws chaw ntawm cov hlwb mus rau qhov chaw mob, suav nrog fibroblasts, endothelial cell, thiab epithelial cell. Cov txheej txheem no pab tsim cov nqaij tshiab thiab cov hlab ntsha (angiogenesis), uas yog qhov tseem ceeb rau kev kho qhov txhab zoo.
Cov Kab Mob Platelet
Kev ua haujlwm tsis zoo lossis kev tsis zoo ntawm cov ntshav platelet tuaj yeem ua rau muaj ntau yam teeb meem kev noj qab haus huv:
– Thrombocytopenia: Cov ntshav platelet tsawg tuaj yeem ua rau los ntshav ntau dhau uas nyuaj rau nres. Qhov mob no tuaj yeem tshwm sim los ntawm ntau yam, suav nrog cov kab mob autoimmune, kev kis kab mob, lossis cov kev phiv tshuaj.
– Thrombocytosis: Cov ntshav platelet ntau tuaj yeem ua rau muaj kev pheej hmoo ntawm kev tsim cov ntshav txhaws, uas tuaj yeem ua rau mob stroke lossis mob plawv nres. Cov ua rau muaj xws li myeloproliferative disorders, kev tsis haum tshuaj rau kev kis kab mob lossis kev o, lossis ib feem ntawm cov kab mob ntev.
– Kev Ua Haujlwm Tsis Zoo ntawm Cov Platelet: Cov Platelets uas tsis ua haujlwm zoo, txawm tias lawv cov lej yog ib txwm muaj, kuj tuaj yeem ua rau muaj teeb meem los ntshav, xws li qee yam kab mob caj ces lossis vim qee yam tshuaj.
Xaus
Cov platelets ua lub luag haujlwm tseem ceeb hauv lub cev ntshav thiab hemostasis. Lawv yog ib feem tseem ceeb ntawm lub cev tiv thaiv kab mob los ntshav thiab muaj lwm yam haujlwm hauv kev kho qhov txhab. Kev nkag siab ntxiv txog cov platelets, ob qho tib si hauv cov mob ib txwm muaj thiab cov mob pathological, yog qhov tseem ceeb rau kev tiv thaiv thiab kho ntau yam kab mob ntshav. Kev tshawb fawb txuas ntxiv tshawb nrhiav ntau yam ntawm cov platelets, suav nrog lawv lub peev xwm hauv kev kho mob thiab kev cuam tshuam hauv kev kho mob.
