Pregnancy and Birth

• Fertilization: The fusion of the male and female gametes to form a zygote
• Gastrulation: the formation of the germ layers
• Ectoderm: outer layer of cells that form the epidermis and nervous system
• Endoderm: the innermost layer of cells or tissue of an embryo in early development, or the parts derived from this, which include the lining of the gut and associated structures.
• Mesoderm: the middle layer of cells or tissues of an embryo, or the parts derived from this (e.g. cartilage, muscles, and bone).
• Implantation: The process by which a fertilized egg implants itself in the uterine wall
• Chorion: produces HCG (maintains corpus lutuem for first three months)
• Amnion: the innermost membrane that encloses the embryo
• Placenta: a flattened circular organ in the uterus that nourishes and maintains the fetus through the umbilical cord.
• HCG: released by the chorion and tells the corpus luteum to release large amounts of progesterone and estrogen
• Progesterone: supports the endometrium, and keeps the uterus calm
• Estrogen: stimulates the mammary gland
• Relaxin: causes the ligaments of the pelvis to loosen
• Oxytocin: released when progesterone levels decrease, causes contractions of the uterus and mammary glands
• Prolactin: stimulates the production of milk
• IVF:

  1. FSH and LH are stopped, preventing estrogen and progesterone secretion
  2. artificial LH and FSH to overproduce follicles
  3. eggs are retrieved and placed in petri dish with sperm for fertilization
  4. One or more that is fertilized is then placed in the uterus
• Amniocentesis: A procedure that involves inserting a needle into the amniotic fluid to obtain a sample of the fetus's cells.
• CVS: takes a small sample of the placenta to determine the karyotype of the fetus