ntshav platelets, uas yog tsim los daws cov ntshav poob tam sim ntawd, hu ua platelets. Lawv khaws cia rau hauv qhov chaw uas muaj kev puas tsuaj rau txhua lub nkoj thiab txhaws lawv nrog lub nres tshwj xeeb.
Cov tsos mob
Nyob rau hauv lub tshuab tsom iav, koj tuaj yeem pom cov qauv ntawm platelets. Lawv zoo li cov discs, txoj kab uas hla ntawm 2 mus rau 5 microns. Qhov ntim ntawm txhua tus yog li 5-10 microns 3.
Raws li lawv cov qauv, platelets yog ib qho nyuaj. Nws yog sawv cev los ntawm cov kab ke ntawm microtubules, daim nyias nyias, organelles thiab microfilaments. Cov thev naus laus zis niaj hnub no tau ua rau nws muaj peev xwm txiav lub phaj tiaj tiaj rau hauv ob qhov chaw thiab ua kom ib leeg tawm ntau thaj chaw hauv nws. Qhov no yog li cas lawv tuaj yeem txiav txim siab cov yam ntxwv ntawm platelets. Txhua phaj muaj ob peb txheej: peripheral cheeb tsam, sol-gel, intracellular organelles. Txhua tus muaj nws lub luag haujlwm thiab lub hom phiaj.
txheej txheej
Thaj chaw peripheral muaj peb txheej txheej. Cov qauv ntawm cov platelets yog xws li tias ntawm nws sab nrauv muaj ib txheej uas muaj plasma yam tseem ceeb rau cov ntshav txhaws, tshwj xeeb.receptors thiab enzymes. Nws thickness tsis tshaj 50 nm. Cov receptors ntawm cov txheej txheem ntawm cov platelets no yog lub luag haujlwm rau kev ua haujlwm ntawm cov hlwb thiab lawv lub peev xwm los ua raws (txuas mus rau subendothelium) thiab sib sau ua ke (muaj peev xwm sib txuas nrog ib leeg).
Cov daim nyias nyias kuj muaj qhov tshwj xeeb phospholipid yam 3 lossis lub npe hu ua matrix. Qhov no yog lub luag haujlwm rau kev tsim cov active coagulation complexes ua ke nrog plasma yam ua lub luag hauj lwm rau cov ntshav txhaws.
Ntxiv rau, nws muaj arachidonic acid. Nws cov ntsiab lus tseem ceeb yog phospholipase A. Nws yog nws uas tsim cov kua qaub uas tsim nyog rau kev sib txuas ntawm prostaglandins. Lawv, nyob rau hauv lem, yog tsim los tsim thromboxane A2, uas yog tsim nyog rau muaj zog platelet aggregation.
YGlycoproteins
Cov qauv ntawm cov platelets tsis txwv rau qhov pom ntawm daim nyias nyias. Nws cov lipid bilayer muaj glycoproteins. Lawv yog tsim los khi platelets.
Yog li, glycoprotein kuv yog cov receptor uas yog lub luag haujlwm rau txuas cov qe ntshav mus rau collagen ntawm subendothelium. Nws ua kom cov adhesion ntawm daim hlau, lawv sib kis thiab lawv khi rau lwm cov protein - fibronectin.
Glycoprotein II yog tsim los rau txhua hom platelet aggregation. Nws muab cov fibrinogen khi rau cov qe ntshav no. Nws yog ua tsaug rau qhov no uas cov txheej txheem ntawm kev sib sau ua ke thiab txo qis (retraction) ntawm cov hlab ntsha txuas ntxiv tsis muaj kev cuam tshuam.
Tab sis glycoprotein V yog tsim los tswj kev sib txuasplatelets. Nws yog hydrolyzed los ntawm thrombin.
Yog tias cov ntsiab lus ntawm ntau yam glycoproteins nyob rau hauv cov txheej txheem ntawm platelet membrane txo qis, qhov no ua rau muaj ntshav ntau ntxiv.
Sol-gel
Nrog rau txheej thib ob ntawm platelets, nyob hauv qab daim nyias nyias, muaj lub nplhaib ntawm microtubules. Cov qauv ntawm platelets hauv tib neeg cov ntshav yog xws li cov tubules yog lawv cov khoom siv cog lus. Yog li, thaum cov phiaj no txhawb nqa, lub nplhaib sib cog lus thiab txav cov granules mus rau qhov chaw ntawm cov hlwb. Yog li ntawd, lawv shrink. Tag nrho cov no ua rau lub secretion ntawm lawv cov ntsiab lus mus rau sab nraud. Qhov no yog ua tau ua tsaug rau ib tug tshwj xeeb system ntawm qhib tubules. Cov txheej txheem no hu ua "granule centralization."
Thaum lub nplhaib microtubule shrinks, qhov tsim ntawm pseudopodia kuj ua tau, uas tsuas yog nyiam kom muaj peev xwm ntawm kev sib sau.
YIntracellular organelles
txheej thib peb muaj glycogen granules, mitochondria, α-granules, tuab lub cev. Qhov no yog qhov chaw hu ua organelle.
Lub cev ntom ntom muaj ATP, ADP, serotonin, calcium, adrenaline thiab norepinephrine. Tag nrho cov ntawm lawv yog tsim nyog rau platelets ua hauj lwm. Cov qauv thiab kev ua haujlwm ntawm cov hlwb no muab cov adhesion thiab kho qhov txhab. Yog li, ADP yog tsim thaum platelets txuas mus rau phab ntsa ntawm cov hlab ntsha, nws tseem yog lub luag haujlwm los xyuas kom meej tias cov phiaj xwm los ntawm cov hlab ntsha txuas ntxiv mus rau cov uas twb tau daig lawm. Calcium tswj cov kev siv ntawm adhesion. Serotonin yog tsim los ntawm platelet thaum cov granules raug tso tawm. Nws yog tus uas ua kom qhov nqaim ntawm lawv cov lumen ntawm qhov chaw ntawm cov hlab ntsha tawg.
Alpha-granules nyob rau hauv thaj tsam ntawm organelles pab tsim cov platelet aggregates. Lawv muaj lub luag haujlwm txhawb kev loj hlob ntawm cov leeg du, kho cov phab ntsa ntawm cov hlab ntsha, cov leeg du.
txheej txheem ntawm cell tsim
Yuav kom nkag siab cov qauv ntawm tib neeg platelets, nws yog ib qho tsim nyog yuav tsum nkag siab tias lawv tuaj ntawm qhov twg thiab lawv tsim tau li cas. Cov txheej txheem ntawm lawv cov tsos yog concentrated nyob rau hauv cov pob txha pob txha. Nws muab faib ua ob peb theem. Ua ntej, ib lub koom haum-tsim megakaryocytic unit yog tsim. Nyob rau ntau theem, nws hloov mus rau hauv megakaryoblast, promegakaryocyte, thiab thaum kawg platelet.
Txhua hnub, tib neeg lub cev tsim tawm txog 66,000 ntawm cov hlwb no rau 1 µl ntawm cov ntshav. Hauv cov neeg laus, cov ntshav ntshav yuav tsum muaj li ntawm 150 txog 375, hauv tus menyuam los ntawm 150 txog 250 x 10 9 / l ntawm platelets. Nyob rau tib lub sijhawm, 70% ntawm lawv ncig los ntawm lub cev, thiab 30% nce hauv tus po. Thaum xav tau, lub cev no cog lus thiab tso cov platelets.
Lub luag haujlwm tseem ceeb
txhawm rau nkag siab tias vim li cas platelets xav tau hauv lub cev, nws tsis txaus kom nkag siab tias dab tsi yog cov yam ntxwv ntawm tib neeg platelets. Lawv yog npaj rau kev tsim cov thawj plug, uas yuav tsum kaw lub nkoj puas. Tsis tas li ntawd, platelets muab lawv qhov chaw txhawm rau txhawm rau ua kom cov ntshav plasma saifolding.
Ntxiv rau, nws tau pom tias lawv xav tau kev tsim kho dua tshiab thiab kho ntau yam ntaub so ntswg puas. Platelets tsim cov yam ntxwv loj hlob tsim los txhawb kev loj hlob thiab kev faib tawm ntawm txhua lub hlwb puas.
Nws yog ib qho tseem ceeb uas lawv tuaj yeem hloov pauv mus rau lub xeev tshiab. Qhov kev txhawb siab rau lawv qhov kev ua kom muaj peev xwm yog qhov hloov pauv hauv ib puag ncig, suav nrog kev ntxhov siab yooj yim.
Ntseeg ntawm platelets
Cov qe ntshav no tsis nyob ntev. Qhov nruab nrab, lub sijhawm ntawm lawv lub neej yog los ntawm 6.9 txog 9.9 hnub. Tom qab qhov kawg ntawm lub sijhawm teev, lawv raug rhuav tshem. Yeej, cov txheej txheem no tshwm sim hauv cov pob txha pob txha, tab sis kuj muaj tsawg dua qhov nws tshwm sim hauv tus po thiab daim siab.
Cov kws tshaj lij paub qhov txawv tsib hom platelets: hluas, laus, laus, cov ntawv khaus thiab degenerative. Feem ntau, lub cev yuav tsum muaj ntau dua 90% ntawm cov hlwb uas paub tab. Tsuas yog nyob rau hauv cov ntaub ntawv no, cov qauv ntawm platelets yuav zoo, thiab lawv yuav ua tau tag nrho lawv cov dej num nyob rau hauv tag nrho.
Nws yog ib qho tseem ceeb kom nkag siab tias qhov txo qis hauv cov ntshav cov qe ntshav no ua rau cov ntshav uas nyuaj rau nres. Thiab qhov nce ntawm lawv tus lej yog qhov ua rau kev txhim kho ntawm thrombosis - cov tsos mob ntawm cov ntshav txhaws. Lawv tuaj yeem txhaws cov hlab ntsha hauv ntau yam kabmob ntawm lub cev lossis thaiv lawv tag nrho.
Feem ntau, nrog ntau yam teeb meem, cov qauv ntawm platelets tsis hloov. Txhua yam kab mob cuam tshuam nrog kev hloov pauv hauv lawv cov concentration.nyob rau hauv lub circulatory system. Kev txo qis hauv lawv tus lej hu ua thrombocytopenia. Yog tias lawv cov concentration nce, peb tab tom tham txog thrombocytosis. Yog tias cov haujlwm ntawm cov hlwb no cuam tshuam, thrombasthenia raug kuaj pom.
