Light and electron microscopic study of contractile elements of normal human full term placenta

ABSTRACT

This work aimed to study the contractile elements present in human term placenta. Ten normal human term placental specimens were obtained after normal deliveries. Five specimens were immersed in 4% glutaraldehyde in phosphate buffer and prepared to be examined by transmission electron microscope. The other five specimens were prepared for light microscopic examination using VVG slain. Light and electron microscopic results conformed the presence of elastic fibres, collagen bundles and myofibroblasts, in large amounts in the ground substance of the stem villous stroma. They were found in association with fetal blood vessels. Elastic fibers, collagen bundles and myofibroblasts are essential components of the stem villous stroma and form a perivascular contractile sheath around fetal blood vessels. 'This contractile sheath is suggested to play an important role in blood propulsion in human placenta