Development/ Pregnancy Flashcards
What is the embryonic period and its duration?
Weeks 0-8
This period is crucial for early development.
What occurs during fertilization?
Fusion of haploid sperm and oocyte to form a diploid zygote
Sperm must penetrate the corona radiata and zona pellucida.
What is the fast block to polyspermy?
Oocyte membrane depolarizes to prevent other sperm from fusing
What is the slow block to polyspermy?
Molecules released in exocytosis harden the zona pellucida
What are the two main cell types formed from the trophoblast?
- Embryoblast
- Trophoblast
What is the role of the trophoblast?
Forms the wall of the blastocyst and becomes part of the placenta
What is the decidua?
Modified portion of endometrium after implantation
It will help form part of the placenta.
What structures develop from the embryoblast during the second week?
- Amnion
- Yolk sac
- Chorion
What is the function of the yolk sac?
Supplies early nutrients, source of blood cells, and some embryonic tissues
What is gastrulation?
Transformation of the bilaminar embryonic disc into a trilaminar embryonic disc
What are the three germ layers formed during gastrulation?
- Ectoderm
- Mesoderm
- Endoderm
What is the function of the allantois?
Early formation of blood vessels and urinary bladder
What develops from the neural tube?
Brain and spinal cord
What are chorionic villi?
Finger-like projections that facilitate gas and nutrient exchange between mother and fetus
What occurs during organogenesis?
All major organs develop between weeks 4-8
What significant development occurs during week 5?
Rapid brain development and substantial head growth
What is the significance of the SRY gene in male development?
Leads to the release of Müllerian inhibiting substance (MIS) causing regression of Müllerian ducts
What is the fetal period’s duration?
Weeks 9 to birth
What is the primary function of the placenta?
Gas and nutrient exchange, protection
What is the difference between true labor and false labor?
- True labor: regular contractions with shortening intervals
- False labor: irregular contractions, no intensification
What complications can occur during pregnancy?
- Placenta previa
- Placental abruption
- Meconium staining
- Preeclampsia
What is a miscarriage?
Expulsion of a fetus from the womb before it can survive independently
What is the role of oxytocin in lactation?
Triggers the milk ejection reflex
What is colostrum?
Nutrient-rich fluid produced before true milk appears
It is high in carbohydrates, protein, and antibodies.
