Questions and Answers
What is the current stage of development of the fertilized egg?
What is the function of the zona pellucida?
What is the term for the process of the embryo breaking out of the zona pellucida?
What is the term for the valleys that form in the endometrial lining in preparation for implantation?
Signup and view all the answers
What is the term for the contact between the outer cell layers of the embryo and the endometrial lining?
Signup and view all the answers
What is the function of the trophoblasts in the process of implantation?
Signup and view all the answers
What is the term for the process by which the embryo becomes firmly embedded in the endometrium?
Signup and view all the answers
What occurs as a result of the trophoblasts invading the endometrial tissue?
Signup and view all the answers
What is happening to the uterine endometrial cells as the embryo implants?
Signup and view all the answers
What forms from the fusion of trophoblasts?
Signup and view all the answers
What are the finger-like projections of syncytiotrophoblasts called?
Signup and view all the answers
What is the function of the membrane of trophoblasts between the fetal and uterine blood vessels?
Signup and view all the answers
What is the name of the structure that forms from the growth of the villi and uterine blood vessels?
Signup and view all the answers
What happens to the cytotrophoblasts as the villi grow?
Signup and view all the answers
What is the purpose of the placenta?
Signup and view all the answers
What is the name of the blood vessels that develop within the villi?
Signup and view all the answers
Study Notes
Development of Blastocyst
- The blastocyst has been fertilized for about a week and has been bouncing around in the fallopian tube before entering the endometrial cavity within the uterus.
- The blastocyst is surrounded by a thick layer of glycoproteins called the zona pellucida, which starts to disintegrate, allowing the outer cells to become exposed.
Implantation Process
- The endometrium is anticipating the blastocyst's arrival and starts proliferating, forming valleys (crypts) for the blastocyst to rest in.
- The blastocyst's outer cells (trophoblasts) come into contact with the endometrium, a process called apposition.
- The trophoblasts multiply and invade into the endometrial tissue, causing adhesion and getting the blastocyst stuck.
Embedding and Development
- The endometrial cells continue to divide and grow, eventually embedding the blastocyst entirely within the endometrium.
- The endometrial blood vessels form pools of blood, which start to coalesce and eventually form a placenta-like structure.
- The trophoblasts continue to divide and fuse, forming multi-nucleated cells called syncytiotrophoblasts, which grow into the endometrium.
- The original trophoblasts that haven't fused are called cytotrophoblasts.
Placenta Formation
- The syncytiotrophoblasts form finger-like projections (villi) that go into the endometrium, increasing the surface area for nutrient transfer.
- The villi are lined with cytotrophoblasts, which help to form fetal blood vessels.
- The fetal blood vessels are in close contact with the uterine blood vessels, allowing for nutrient and waste transfer.
- Over time, the structure continues to grow, eventually forming the placenta, which lines the entire inside of the uterine cavity.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
This quiz covers the first week of embryonic development, from fertilization to implantation in the uterus.