Early embryogenesis: limb development Flashcards
What epithelia makes the maternal part of the placenta?
Endometrium
What are the phases of the menstrual cycle?
Menstrual phase: 1-4
Proliferative/follicular phase: 5-14
Secretory/luteal phase: 15-28
Implantation often occurs on day ___.
21
Ovulation often occurs on day ____.
14
What are the 2 different aging systems for a fetus?
- Fertilization (conception) age: dates pregnancy from the time of fertilization
- Menstrual/gestational/clinical age: used by clinicians and dates the pregnancy from the woman’s last period. 2 weeks greater than fertilization age.
By day ___ of development, all cells for organ systems are in place.
56
What is the most sensitive stage of development?
Week 3
What is the embryonic stage?
First 8 weeks
Zygote formation
Cell division
Implantation
Organ formation
What is the fetal stage?
Week 9-birth
Are there any birth defects associated with weeks 0-2?
Nope!
What is the window of fertilization?
1-2 days after ovulation
When does implantation occur?
Day 6-7
The blastocyst is composed of ____ and ____.
ICM and ECM
What is the outer cell mass called? What does it develop into?
Trophoblast, extra-embryonic tissues (e.g. placenta)
What is the inner cell mass called? What does it develop into?
Embryoblast, embryonic cells and layers
What is the most common site of ectopic pregnancy?
Ampulla
What is the usual site of implantation?
Posterior superior wall
What 2 layers does the trophoblast divide into upon implantation?
- Cytotrophoblast
2. Syncytiotrophoblast
What does syncytiotrophoblast secrete?
hCG to maintain pregnancy (acts on embryo)
What is the decidua?
The name for a pregnant endometria. The cells become larger and rounder and filled with glycogen and lipids
What 2 cell layers does the embryoblast divide into?
- Epiblast - DORSAL layer
- Hypoblast - VENTRAL layer
The hypoblast does NOT contribute to the cells of the developing embryo
What makes the yolk sac and what does it store?
Made from hypoblast. Contains nutrients for development.