【摘要】 作者采用组织切片方法,对28头湖羊不同胎龄的胎儿,就皮肤的表皮、真皮、皮肤厚度、结缔组织细胞以及毛囊、附属腺、毛囊群等成份,进行发生和生长的研究。结果表明,湖羊皮肤诸成份的发生可归纳为四个连续阶段。第一阶段:胎龄约在1.5月,胚胎性表皮由单层变成复层,真皮区为间充质细胞,但有分化趋向。胎龄45～66天时,普遍发生初级毛囊原基。第二阶段:胎龄约在3个月,胚胎性表皮增厚,分化和变性,真皮区分化为上下二层,初级毛囊强烈生长和分化。95天时,次级毛囊大量发生。汗腺和皮脂腺也先后发生。第三阶段:胎龄约在3.5月,胚胎性表皮明显变性和退化,角化层脱落,厚度减少,真皮大体分化为表皮下层,中间层和网状层,初级毛囊发育成熟,粗毛穿出皮肤,次级毛囊迅速生长,毛囊群发育基本完成。第四阶段:胎龄约4.5月,胚胎性表皮变为一般表皮,很薄,细胞层次和界线不清。真皮层次和初生羔羊相似,部分次级毛囊发育成熟,其中细毛穿出皮肤。毛囊群清晰,皮肤各成份发生和分化基本结束,开始急剧增厚。 研究显示,皮肤一些成份发生和分化因部位不同而有差异,毛囊发生和粗毛穿出皮肤,不仅有由前到后的时间梯度,而且有从腹到背的梯度。从130天背部和腹部毛囊群发育来看,毛囊密度低、次级毛囊对初级毛囊比值小,以及次级毛囊成熟早,都?更多还原

【Abstract】 Twin fetuses of diff(?)ent prenatal stages were taken from 28 ewes of the Hu (Lake) sheep, a native breed well-known for its lamb-fur production in the Tai Lake region. Cross-sections were made from skin samples histologically to study the development and growth of the peridermis, dermis, thickness of the skin,cells of the connective tissue, components of the hair follicles and the accessory glands as well as hair follicle mass.The result indicated that four successive stages could be involved in the development of the skin components. At the first stage, about 1.5 months of the fetal age, the embryonic peridermis turned from single layer to multiple layer and mesenchymal cells appeared in the dermal region, tending to differentiation.On days 45 to 66, the premordia of the primary hair follicles developed extensively. At the second stage, during 2-3 months of the fetal life, the embryonic peridermis became thickened, differentiated and degenerated, the derminal region differentiated into upper and lower layers, and the primary hair follicles developed intensively and differentiated. On 95th day, the secondary hair follicles developed markedly; the sweat glands and the sebaceous glands also appeared in succession. At the third stage, about 3.5 months, the embryonic peridermis became degenerated and retrogressed apparently, its cornified layer desquamated and lessened in thickness. The dermis in the main became differentiated into three strata: subperidermal, intermediate and reticular. Meanwhile, the primary hair follicles matured, wool penetrated through the skin and the secondary hair follicles grew rapidly. The development of the hair follicle mass completed basically. At the fourth stage, about 4.5 months of the fetal life, the embrvonic peridermis, lessening in its thickness, became the normal peridermis, in which the layers of cells and their demarcation were not clearly distinguished and the layers of the dermis were similar to those of the newborn lamb. Secondary hair follicles partially matured from which fine wool penetrated through the skin.The hajr follicle masses were apparent.The development and differentiation of the skin component were finished in the main and the skin became thickened intensively.The result also demonstrated that the development and differentiation of certain skin components varied with different positions where the skin samples were taken, As to the development of the hair follicles and the penetration of the wool through the skin, there exist the time gradients not only from anterior to posterior parts but also from abdominal to dorsal.Taking the development of the hair follicle mass at the dorsal and abdominal parts on 130th day as an example, lower density of the hair follicles, less proportion of the secondary hair follicles to the primary ones and early maturing of the secondary hair follicles could be indicated as the proper characters of the Hu sheep breed.更多还原