Growth and development (PRENATAL) Flashcards
Describe the process of cleavage, formation of the morula and blastocyst.
After fertilization, zygote undergoes rapid mitotic divisions (cleavage) to form a solid ball of cells
-Cells produced are blastomeres
-Solid ball of cells from progression of cleavage(16-32) cells
-Morula divides and develops fluid filled cavity called blastocoel
-Blastocyst is hollow sphere of cells with embryo blast that’ll form the embryo (Crucial for implantation)
Describe the formation of the placenta, and explain its functions
Forms from trophoblast after implantation
-Consists of three layers:inner amnion, outer chorion, decides of maternal endometrium
List 3 functions of hCG.
Maintains corpus luteum for progesterone production
Supports uterine lining development
Potentially influencing maternal immune responses
Theca cell androstenedione production
Explain the hormonal changes that occur in the maternal body during pregnancy
Increases in estrogen, progesterone, human chorionic gonadotropic(hCG)
which supports development, maintains pregnancy, prepares for childbirth and lactation
List the structures derived from the primitive tissues of the ectoderm, mesoderm, and endoderm
Ectoderm forms nervous system, skin, linings of mouth, nose, anus
Mesoderm: Gives rise to muscles, bones, and connective tissues, heart, gonads
Endoderm: Digestive system, Respiratory system, thyroid, thymus, lining of bladder
Explain the function of the amniotic fluid, yolk sac and the allantois.
Amniotic fluid: Cushions and protects the developing embryo, safeguarding embryo
Yolk sac: provide early nutrition and aids in blood cell development, formation of first blood cells, contributes to gastrointestinal reproductive systems
Allantois: Facilitates gas exchange and waste removal; contributes to formation of placenta and umbilical cord; develops from yolk sac
Explain why the embryonic period is so critical.
Fundamental structures and organs of developing embryo form, making it highly susceptible to environmental factors and potential for major birth defects
- Organogenesis takes place during period where organs form
-Neural tube forms
-miscarriages occur during this stage
Explain how the fetal cardiovascular system is adapted to intrauterine life.
shunts that bypass lungs and liver
placenta for gas exchange
Trace the pathway of blood from the placenta to the fetus and back to the placenta.
Placenta to fetus
-Umbilical vein>ductus verosus> Inferior vena cava> Right atrium> foramen ovale> left ventricle> aorta> body tissues
Fetus to placenta
-Umbilical arteries > placenta
Discuss the events that occur during the birth process.
Dilation and effacement: Starts with regular contractions; ends when cervix is fully dilated
Pushing and delivery: Begins once cervix is fully dilated ends with delivery
Delivery of placenta: Baby is delivered and placenta is out through expulsion or afterbirth
Explain positive feedback and the role of hormones in the expulsion of the fetus and the afterbirth.
Positive feedback loop involving hormone oxytocin amplified uterine contractions, leading to expulsion of fetus and afterbirth
Cervix stretching triggers more oxytocin which causes stronger contractions
Detail the roles of prolactin and oxytocin in milk production and secretion.
Prolactin stimulates milk production in the mammary glands while oxytocin triggers milk ejection reflex (contraction of smooth muscles) that forces milk into the ducts and through the nipple
