Which of the trophoblast does not invade spiral arterioles:-
Ans. (d) InterstitialRef: Williams Obstetrics 25th Ed; Page No-88* After implantation; trophoblast giving rise to villous and extra villous trophoblasts.* Extra villous trophoblasts contact with various maternal cell types because it migrate into the decidua and myometrium and also penetrate maternal vasculature.* Extra villous trophoblasts are found outside the villus and it is further subdivided into endovascular and interstitial trophoblasts. * Interstitial trophoblasts invade the decidua and surround spiral arteries.* Endovascular trophoblasts invade and transform spiral arteries during pregnancy to create low-resistance blood flow that is characteristic of the placenta.
Extravillous
Endovascular
Tertiary villus
Interstitial
Fetus Placenta & Fetal Membrane