28. Human Development

The trophoblast eventually differentiates into two layers. Which of these layers erodes the endometrium and begins projecting extensions into the uterine lining?

The process of implantation is usually complete by approximately:

After implantation, how does the developing embryo obtain nutrients? What structures and processes are involved?

The life span of the ovarian corpus luteum is extended for nearly three months after implantation, but otherwise it deteriorates.

(a) Explain why this is so.

(b) Explain why it is important that the corpus luteum remain functional following implantation.