How does the blastocyst become embedded in the uterine lining during implantation?

• A. The blastocyst is pushed into the uterine lining by uterine contractions.
• B. The blastocyst uses cilia to burrow into the uterine lining.
• C. The blastocyst secretes enzymes that degrade the uterine lining, allowing it to embed.
• D. The uterine lining engulfs the blastocyst through phagocytosis.

Answer: (C)

Verified step by step guidance

1. Understand the structure of the blastocyst: The blastocyst is a structure formed in the early development of mammals. It possesses an outer layer called the trophoblast and an inner cell mass that will eventually form the embryo.
2. Recognize the role of the trophoblast: The trophoblast cells play a crucial role in implantation. They are responsible for interacting with the uterine lining and facilitating the embedding process.
3. Learn about enzyme secretion: The trophoblast cells secrete enzymes that degrade the extracellular matrix of the uterine lining. This enzymatic activity helps to break down the tissue, allowing the blastocyst to embed itself into the lining.
4. Consider the process of implantation: As the enzymes degrade the uterine lining, the blastocyst gradually embeds itself into the endometrium, the inner lining of the uterus. This process is essential for establishing a connection between the mother and the developing embryo.
5. Understand the significance of implantation: Successful implantation is critical for the continuation of pregnancy. It allows the blastocyst to access nutrients and oxygen from the mother's blood supply, which are necessary for its growth and development.