Implantation

Published on April 30, 2019   43 min
0:00
My name is John Aplin, and I'm a Professor of Reproductive Biomedicine at the University of Manchester in the UK, and I'm going to be telling you about embryo implantation.
0:12
What we're going to cover in this presentation is the idea that there are two clocks, the maternal clock and the preparation of the endometrium, and the embryonic clock that starts at fertilization, and how they have to be synchronized. Implantation in the humans is interstitial, and I'll be explaining that concept to you. I'll be explaining a hypothesis that the maternal environment, the endometrium is initially not receptive to the implanting embryo and has to be rendered permissive, and then we'll talk a bit about the corpus luteum which is a structure in the ovary which has to be rescued from atrophy in order for pregnancy to continue. Then finally, at the end we'll just say a little bit about what happens after implantation in terms of delivering the early nutrient supply to the embryo.
1:03
So the maternal clock is set at ovulation, and the image in this slide is a chance event when Dr. Jacques Donnez was carrying out some routine abdominal surgery, a hysterectomy in fact, and notice that the egg was just about to be ovulated, and this picture is of an ovarian follicle. So the red structure is just over two centimeters in diameter, and there is a swelling at the surface of the ovary, and you can see just to the right, his surgical instrument. The color of the follicle tells us that it's highly vascularized. There's been a lot of active development of blood vessels to supply the developing follicle, and to help the egg to mature, and the egg is just in the process as you can see of escaping from the follicle having broken down the follicular surface.