人體血管有多長
若把(ba)一(yi)個(ge)成年人身體里所有的(de)動脈(mo)(mo)血管、靜脈(mo)(mo)血管和毛細(xi)血管連接在一(yi)起,約有15萬公里長,這個(ge)長度可(ke)繞地球(qiu)兩周半左右(you)。
人體血管分類
1、動(dong)(dong)脈(mo)血(xue)管(guan):動(dong)(dong)脈(mo)是(shi)運(yun)送血(xue)液(ye)離(li)開(kai)心(xin)的血(xue)管(guan),從心(xin)室(shi)發(fa)出后,反復分支,越分越細(xi),最后移(yi)行(xing)于毛細(xi)血(xue)管(guan)。動(dong)(dong)脈(mo)管(guan)壁較(jiao)厚,能(neng)承受較(jiao)大的壓力。大動(dong)(dong)脈(mo)管(guan)壁彈性(xing)纖維較(jiao)多(duo),有較(jiao)大的彈性(xing),心(xin)室(shi)射血(xue)時(shi)管(guan)壁擴(kuo)張,心(xin)室(shi)舒張時(shi)管(guan)壁回縮,促(cu)使血(xue)液(ye)繼續向前流動(dong)(dong)。中、小動(dong)(dong)脈(mo),特別是(shi)小動(dong)(dong)脈(mo)管(guan)壁的平滑肌(ji)較(jiao)發(fa)達,可在神(shen)經體液(ye)調節(jie)下(xia)收縮或(huo)舒張,以改(gai)變管(guan)腔和大小,影響局部血(xue)流阻力。
2、靜(jing)脈(mo)(mo)(mo)血(xue)(xue)管(guan):血(xue)(xue)液經過毛細血(xue)(xue)管(guan),流(liu)回心臟的血(xue)(xue),或是(shi)從心臟迸射到肺的血(xue)(xue)叫(jiao)靜(jing)脈(mo)(mo)(mo)血(xue)(xue)。靜(jing)脈(mo)(mo)(mo)的管(guan)壁薄,彈(dan)性(xing)較差,有靜(jing)脈(mo)(mo)(mo)瓣,血(xue)(xue)液流(liu)速(su)慢,易發(fa)生曲張(zhang)(尤其(qi)是(shi)下肢),因為血(xue)(xue)液在毛細血(xue)(xue)管(guan)和機體的組織(zhi)交換過營養物(wu)質,所以靜(jing)脈(mo)(mo)(mo)血(xue)(xue)呈暗(an)紅色。
3、毛(mao)細(xi)血(xue)(xue)(xue)(xue)管(guan):毛(mao)細(xi)血(xue)(xue)(xue)(xue)管(guan)又(you)稱(cheng)微(wei)(wei)(wei)(wei)(wei)血(xue)(xue)(xue)(xue)管(guan),是指心血(xue)(xue)(xue)(xue)管(guan)系統的(de)微(wei)(wei)(wei)(wei)(wei)細(xi)血(xue)(xue)(xue)(xue)管(guan),它們在(zai)顯微(wei)(wei)(wei)(wei)(wei)鏡(jing)下才能見到(dao)。微(wei)(wei)(wei)(wei)(wei)血(xue)(xue)(xue)(xue)管(guan)指通(tong)(tong)(tong)連(lian)小動脈(mo)和(he)小靜(jing)脈(mo)間的(de)細(xi)小血(xue)(xue)(xue)(xue)管(guan),分布于各種組織(zhi)和(he)器官(guan)中,分支通(tong)(tong)(tong)連(lian)成(cheng)網,故也(ye)稱(cheng)終末血(xue)(xue)(xue)(xue)管(guan)床。按(an)血(xue)(xue)(xue)(xue)管(guan)分支的(de)順序(xu),微(wei)(wei)(wei)(wei)(wei)血(xue)(xue)(xue)(xue)管(guan)主(zhu)要包括(kuo)微(wei)(wei)(wei)(wei)(wei)動脈(mo)、毛(mao)細(xi)血(xue)(xue)(xue)(xue)管(guan)和(he)微(wei)(wei)(wei)(wei)(wei)靜(jing)脈(mo);有些還(huan)有直(zhi)接通(tong)(tong)(tong)連(lian)微(wei)(wei)(wei)(wei)(wei)動脈(mo)和(he)微(wei)(wei)(wei)(wei)(wei)靜(jing)脈(mo)的(de)兩種短(duan)路(lu):直(zhi)捷通(tong)(tong)(tong)路(lu)和(he)動靜(jing)脈(mo)吻(wen)合。
人體血管作用
血(xue)(xue)(xue)(xue)管(guan)(guan)(guan)是(shi)生物運送(song)血(xue)(xue)(xue)(xue)液(ye)(ye)的(de)管(guan)(guan)(guan)道,依(yi)運輸(shu)方(fang)向可分為(wei)動(dong)(dong)脈(mo)、靜(jing)脈(mo)與毛細血(xue)(xue)(xue)(xue)管(guan)(guan)(guan)。動(dong)(dong)脈(mo)從(cong)心(xin)(xin)臟將血(xue)(xue)(xue)(xue)液(ye)(ye)帶至身體(ti)組(zu)(zu)(zu)織,靜(jing)脈(mo)將血(xue)(xue)(xue)(xue)液(ye)(ye)自(zi)組(zu)(zu)(zu)織間(jian)帶回(hui)心(xin)(xin)臟,微血(xue)(xue)(xue)(xue)管(guan)(guan)(guan)則(ze)連接動(dong)(dong)脈(mo)與靜(jing)脈(mo),是(shi)血(xue)(xue)(xue)(xue)液(ye)(ye)與組(zu)(zu)(zu)織間(jian)物質交換(huan)的(de)主要場(chang)所。各種生物擁有(you)的(de)血(xue)(xue)(xue)(xue)管(guan)(guan)(guan)型態各不相同。開放(fang)式(shi)循(xun)環生物,如昆蟲,只(zhi)有(you)動(dong)(dong)脈(mo)。血(xue)(xue)(xue)(xue)液(ye)(ye)自(zi)動(dong)(dong)脈(mo)流出(chu)直接接觸身體(ti)組(zu)(zu)(zu)織,再由心(xin)(xin)臟上的(de)開孔回(hui)收血(xue)(xue)(xue)(xue)液(ye)(ye)。閉鎖(suo)式(shi)循(xun)環生物,如哺乳(ru)類(lei)、鳥類(lei)、爬蟲類(lei)、魚類(lei),則(ze)由動(dong)(dong)脈(mo)連接毛細血(xue)(xue)(xue)(xue)管(guan)(guan)(guan)再接至靜(jing)脈(mo),最后回(hui)歸心(xin)(xin)臟。
人體血管是怎么形成的
1、生長因子
血管內皮(pi)生(sheng)(sheng)(sheng)(sheng)長因子(zi)(VEGF),為單一基因編(bian)碼的同源二聚體糖蛋(dan)(dan)白(bai),能直接(jie)刺激血管內皮(pi)細(xi)(xi)胞(bao)(bao)移動、增(zeng)殖(zhi)及(ji)分裂,并(bing)(bing)增(zeng)加微(wei)血管通(tong)透性(xing)(xing)。它是針(zhen)對內皮(pi)細(xi)(xi)胞(bao)(bao)特異(yi)性(xing)(xing)最(zui)高(gao),促(cu)(cu)血管生(sheng)(sheng)(sheng)(sheng)長作(zuo)用(yong)最(zui)強的有絲分裂原(yuan)(yuan)。VEGF與(yu)內皮(pi)細(xi)(xi)胞(bao)(bao)上(shang)的兩種受體KDR和(he)Flt-1高(gao)親(qin)和(he)力結合后,直接(jie)刺激血管內皮(pi)細(xi)(xi)胞(bao)(bao)增(zeng)殖(zhi),并(bing)(bing)誘導(dao)其(qi)遷移和(he)形成(cheng)管腔樣結構;同時還可增(zeng)加微(wei)血管通(tong)透性(xing)(xing),引起血漿(jiang)蛋(dan)(dan)白(bai)(主要是纖維蛋(dan)(dan)白(bai)原(yuan)(yuan))外(wai)滲,并(bing)(bing)通(tong)過(guo)誘導(dao)間質產生(sheng)(sheng)(sheng)(sheng)而促(cu)(cu)進(jin)體內新生(sheng)(sheng)(sheng)(sheng)血管生(sheng)(sheng)(sheng)(sheng)成(cheng)。VEGF在(zai)血管發生(sheng)(sheng)(sheng)(sheng)和(he)形成(cheng)過(guo)程中起著中樞性(xing)(xing)的調控作(zuo)用(yong),是關鍵的血管形成(cheng)刺激因子(zi)。堿性(xing)(xing)成(cheng)纖維細(xi)(xi)胞(bao)(bao)生(sheng)(sheng)(sheng)(sheng)長因子(zi)(bFGF)。TNF-α是一類具有血管活性(xing)(xing)的細(xi)(xi)胞(bao)(bao)因子(zi),可誘導(dao)異(yi)位子(zi)宮內膜炎性(xing)(xing)細(xi)(xi)胞(bao)(bao)因子(zi)MCP-1,IL-6和(he)IL-8等的釋放,促(cu)(cu)進(jin)異(yi)位內膜及(ji)基質細(xi)(xi)胞(bao)(bao)增(zeng)殖(zhi)及(ji)炎性(xing)(xing)細(xi)(xi)胞(bao)(bao)浸潤,新生(sheng)(sheng)(sheng)(sheng)血管形成(cheng),組織粘連,從而形成(cheng)異(yi)位病灶。
血管(guan)生(sheng)(sheng)(sheng)成(cheng)過程(cheng)中需要血管(guan)內皮細(xi)(xi)(xi)胞(bao)(bao)(EC)與(yu)細(xi)(xi)(xi)胞(bao)(bao)外基質間(jian)(jian)(jian)、EC與(yu)EC間(jian)(jian)(jian)及(ji)EC與(yu)其他周(zhou)圍細(xi)(xi)(xi)胞(bao)(bao)間(jian)(jian)(jian)的相互作用(yong)。這種(zhong)作用(yong)是(shi)粘附(fu)因(yin)子完成(cheng)的,其中基質金(jin)屬蛋白(bai)酶(MMP)通(tong)過降解(jie)基底(di)膜糖蛋白(bai)及(ji)細(xi)(xi)(xi)胞(bao)(bao)外基質成(cheng)分(fen),啟(qi)動了(le)內皮細(xi)(xi)(xi)胞(bao)(bao)的激(ji)活(huo)和遷(qian)移(yi),整合素家(jia)族通(tong)過和不同配基結(jie)合,介導血管(guan)內皮細(xi)(xi)(xi)胞(bao)(bao)的遷(qian)移(yi)和黏附(fu),有(you)助于(yu)新生(sheng)(sheng)(sheng)血管(guan)的成(cheng)熟和穩定,細(xi)(xi)(xi)胞(bao)(bao)黏附(fu)因(yin)子(ICAM-1)可(ke)產生(sheng)(sheng)(sheng)免(mian)疫(yi)抑制和降低自然(ran)殺(sha)傷細(xi)(xi)(xi)胞(bao)(bao)的殺(sha)細(xi)(xi)(xi)胞(bao)(bao)毒性,有(you)助于(yu)異位組(zu)織逃避(bi)機體免(mian)疫(yi)系統和自然(ran)殺(sha)傷細(xi)(xi)(xi)胞(bao)(bao)的的殺(sha)傷,促進異位組(zu)織侵入后的血管(guan)生(sheng)(sheng)(sheng)成(cheng)。
血(xue)管生(sheng)成機制(zhi)復雜(za),參與并促(cu)進(jin)血(xue)管生(sheng)成的(de)因(yin)子也(ye)眾多,EMT腹腔液中巨噬細胞數量明顯(xian)增加,其分泌的(de)TNF-α和(he)IL-8可(ke)以促(cu)進(jin)血(xue)管內皮(pi)細胞的(de)增殖,轉化生(sheng)長因(yin)子-β(TGF-β),血(xue)小板衍生(sheng)內皮(pi)細胞生(sheng)長因(yin)子(PD-ECGF),乙酰肝素(su)酶,血(xue)管生(sheng)成素(su)(angs),骨生(sheng)成素(su)(OPN),環氧(yang)化酶(COX-2),缺氧(yang)誘導因(yin)子-1,層(ceng)粘連蛋白(LN),胎盤生(sheng)長因(yin)子(PLGF),Survivin,促(cu)紅細胞生(sheng)成素(su)(Epo)均參與了EMT血(xue)管形成過程。
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