Fourteen normal human placental villi at a fetal age of 5-8 weeks were examined withelectron microscope. The results were vide infra.(1)The cytotrophoblasts were characterized by largenucleus with less heterochromatin...Fourteen normal human placental villi at a fetal age of 5-8 weeks were examined withelectron microscope. The results were vide infra.(1)The cytotrophoblasts were characterized by largenucleus with less heterochromatin and prominent nucleolus with a number of free polyribosomes as well asscattered mitochondria in the cytoplasm.(2) There was a layer of dense microvilli on the surface of thesyncytiotrophoblastic cells.The size and shape of microvilli were variable. Usually fine globular expansions were present at the apical pole of microvilli and the cell membrane between the base of microvillihad invaginations into the cytoplasm forming small vesicles and tubules. Rough endoplasmic reticulum,free polyribosomes,mitochondria, lipid droplets and few myelinlike figures were also found in the cytoplasm.Part of cytoplasm penetrated into the interspaces of cytotrophoblastic cells and became in directcontact with the basement membrane.(3) Numerous desmosomes were seen between the cells of cytotrophoblast and syncytiotrophoblast.And (4) in the strom a of villi,mesenchymal cells were abundant inrough endoplasmic reticulum and well developed Golgi complex. Mesenchymat cells were markedlyfunctionally active. Ultrastructural characteristics of placental villin in connexion with their functionwere discussed.展开更多
文摘Fourteen normal human placental villi at a fetal age of 5-8 weeks were examined withelectron microscope. The results were vide infra.(1)The cytotrophoblasts were characterized by largenucleus with less heterochromatin and prominent nucleolus with a number of free polyribosomes as well asscattered mitochondria in the cytoplasm.(2) There was a layer of dense microvilli on the surface of thesyncytiotrophoblastic cells.The size and shape of microvilli were variable. Usually fine globular expansions were present at the apical pole of microvilli and the cell membrane between the base of microvillihad invaginations into the cytoplasm forming small vesicles and tubules. Rough endoplasmic reticulum,free polyribosomes,mitochondria, lipid droplets and few myelinlike figures were also found in the cytoplasm.Part of cytoplasm penetrated into the interspaces of cytotrophoblastic cells and became in directcontact with the basement membrane.(3) Numerous desmosomes were seen between the cells of cytotrophoblast and syncytiotrophoblast.And (4) in the strom a of villi,mesenchymal cells were abundant inrough endoplasmic reticulum and well developed Golgi complex. Mesenchymat cells were markedlyfunctionally active. Ultrastructural characteristics of placental villin in connexion with their functionwere discussed.
