细胞分化贯穿于生物体的整个生命过程,尤其在胚胎期最频繁、最典型。所谓分化,简单地说就是细胞之间有了不同。它始于受精卵。受精卵不断卵裂,形成桑椹胚。虽然桑椹胚的各个细胞(卵裂球)在大小、形态上有很多不同,但它们都是全能性的,可以增殖、演变和分化,从而形成一个完整胚胎所需要的所有种类的细胞。卵裂后不久,在桑椹胚的中心会出现一个腔隙,即囊胚腔。突伸于此腔 Cell differentiation throughout the entire life process of the organism, especially in the embryonic period of the most frequent and most typical. The so-called differentiation, simply put there is a difference between the cells. It starts with fertilized eggs. Fertilized eggs continue to cleavage, the formation of morula. Although each blastomere of morula has many different sizes and morphologies, all of them are pluripotent and proliferate, evolve and differentiate to form all kinds of cells needed by a complete embryo. Shortly after the cleavage, there is a lacuna in the center of the morulae, the blastocoel. Protruding in this cavity