Lesson 4 Part 1 Zygote Formation

University:
California State University, Northridge
Course:
BIOL 211 | Human Anatomy
Academic year:

2022
Views:

446

Pages:

2
Author:

folclord7m

Lesson 4: Part 1: Zygote Formation Q: What are the 6 steps of zygote formation? A: Fertilization, cleavage, morula, blastocyst formation, hatching, implantation. Q: How many cells are in the morula? A: 8–16 cells. Q: Draw out the formation of blastocysts. A: [Draw the morula developing a fluid-filled cavity (blastocoel), forming the inner cell mass and trophoblast layer.] Q: Where do cells organize themselves in? A: The uterus. Q: Infertility is caused by? A: Failure of the blastocyst to hatch. Q: Abnormal implantation in the uterine lining is caused by? A: Premature hatching. Q: How does the blastocyst come in contact with the uterine wall? A: Through apposition, adhesion/attachment, and trophoblast invasion. Q: When does the embryo break free from the zona pellucida? A: During hatching (day 5–6). Q: Which day does hatching occur? A: Day 5–6. Q: Which day does apposition occur? A: Day 7 (end of first week). Q: Which day does attachment occur? A: Day 7–8. Q: Which day does trophoblast invasion occur? A: Day 5–6. Q: The blastocyst orients itself such that the _____ apposes to the endometrial surface. A: Trophoectoderm overlying the inner cell mass. Q: Attachment is reliant on the _______ event. A: Receptor-mediated event. Q: _________ transmigrate to the uterine walls across the ________ epithelium. A: Trophoblasts; luminal. Q: Trophoblast invasion creates _____ placenta. A: Haemochorial placenta. Q: Trophoblasts differentiate by producing ________ and ________; these degrade extracellular matrix. A: Anchoring cytotrophoblast and syncytiotrophoblast. Q: Syncytiotrophoblast produces ___ enzyme, leading to _____ of endometrial epithelial cells. A: Lytic enzymes; apoptosis. Q: Digestion of endometrial tissue creates spaces known as _____. A: Lacunae. Q: Proliferating cellular trophoblast forms _______ villi. A: Chorionic.