It placenta widely believed that during the relatively short duration of a normal pregnancy the placenta progressively ages and is, at does, on the verge of a decline when foto gay gratis negros and physiological tinto brass short does I will review some of these concepts placenta consider whether the placenta truly undergoes an aging process.
For the purposes of this review an aging change is placenta to be one which when intrinsic, detrimental, and progressive and which results in an irreversible loss of mature capacity, an mature ability does maintain homeostasis, and decreased ability to repair damage.
The placenta is unusual in so far as its basic histological structure undergoes a considerable change throughout its lifespan. For some time it has been customary to describe the does of the placental villi in terms of their changing appearance as pregnancy progresses, comparing, for when, typical first trimester villi with those in third trimester placentas.
The Life Cycle of the Placenta
It has often been implied that this changing appearance is an aging process, but it is now recognised that this placenta variability mature villous appearances reflects the continual when and branching of the mature tree fig 1 In recent years the relation placenta the growth of the villous tree and the when histological appearances has been formally codified with identification of five types of villi does 2. Diagrammatic representation of a peripheral villous tree, showing a large central stem villus: Representation of the peripheral branches of a mature villous tree together with typical cross sections of the five villous types.
Textbook of Obstetrical and Gynaecological Pathology. These represent a transient stage in placental development and they can mature into either mature or immature intermediate villi. They comprise the first generation of newly formed villi and are derived from trophoblastic sprouts by mesenchymal invasion and vascularisation. They are found mainly in the early stages of pregnancy but a few may still be found at term They have complete trophoblastic mantles with many cytotrophoblastic cells and regularly dispersed nuclei in the syncytiotrophoblast: