Image A8b7 Complex Description

Diagram showing the different stages of an egg’s development as it travels down the fallopian tube and into the uterus after being fertilized. The uterus and one fallopian tube with an ovary behind it are shown. There is an opening in the ovary just below the finger-like projections at the end of the fallopian tube with lines indicating that an egg pictured as simple concentric circles has been released. An arrow points to the next picture of a single sperm cell entering the egg at the moment of fertilization. The next version of the egg shows it further along the fallopian tube with two new concentric circles inside the outer circle to indicate that cells have started to divide. An arrow points to the next version of the egg, further down the fallopian tube, now with four cells pictured inside it. Another arrow points to the egg shown further down the fallopian tube and now filled with smaller cells. The next arrow points to the egg entering the uterus and now larger and completely filled with smaller cells. The final arrow points to the egg resting against the lining on the side of the uterus, with a layer of cells around its circumference and other cells coming out of the egg and entering the uterine lining to show the moment of implantation when the fertilized egg embeds itself into the lining of the uterus and a pregnancy begins.