【正文】
概念: 體內(nèi)外某些因素觸發(fā)細(xì)胞內(nèi)預(yù)存的死亡程序,導(dǎo)致細(xì)胞主動(dòng)性死亡的方式,不伴炎癥反應(yīng),在形態(tài)和生化特征上都有別于壞死。 Definition: Apoptosis is referred to the death of a cell or a group of cells without destroyed cellular membrane and inflammatory reaction. It is also termed programmed cell death (PCD) because it relates to gene regulation. 生化特征: 在細(xì)胞內(nèi)核酸內(nèi)切酶作用下, DNA降解,形成寡核苷酸片段。 形態(tài)特征: 凋亡的細(xì)胞體積縮小,圓形,胞質(zhì)致密;凋亡小體形成。 細(xì)胞凋亡小體 apoptosis body ▼ ↙ 意義: ( 1)生理上: 胚胎發(fā)生、成熟細(xì)胞的新 陳代謝、生理性退化。 ( 2)病理上: 腫瘤、自身免疫性疾病等。 發(fā)生機(jī)制: 死亡基因的啟動(dòng),即程序性死亡。 與壞死的比較: Necrosis Apoptosis ______________________________________________________ Stimulitoxins hypoxia, insult physiological, pathological ATP depletion without ATP depletion Patterns Groups of neighboring cells Single cells Histologic Cell swells。 Cell contracts。 anelles swell。 disruption chromatin condenses of anelles occurs apoptotic bodies form membrane lysed membrane intact DNA Diffuse and random Internecleosomal cleavage Mechanism No DNA, protein New protein synthesis Tissue reaction Inflammation No