Hormonal Changes and Reproductive Technologies: From Pregnancy to Stem Cells - Prof. Dougl, Study notes of Biology

Download Hormonal Changes and Reproductive Technologies: From Pregnancy to Stem Cells - Prof. Dougl and more Study notes Biology in PDF only on Docsity! 16 April Progesterone > estrogen throughout most of pregnancy Progesterone has relaxing effect on uterine wall No contractions Estrogen > progesterone (switch occurs right before parturition) Stimulates contraction Prostaglandin release Puberty – E2 increases duct growth and branching, P4 promotes alveoli growth Pregnancy – E2, P4, prolactin promote breast enlargement. No milk production! E2 and P4 block prolactin’s effect on milk production After pregnancy E2 and P4 drop → prolactin stimulates milk production Lactation: Milk Secretion The hormonal control of milk secretion and release Suckling, crying → hypothalamus → pituitary Increase oxytocin – contraction myoepithelial cells → milk ejection Increase prolactin – milk production Dopamine (opposes prolactin) levels drop Maternal age ↑ → ↑ spontaneous abortions, ↓ fertility Sperm count declines with age Assisted Reproductive Techniques (ART) Artificial insemination Hormone assisted ovulation In vitro fertilization (IVF) – Louise Brown (1978) Intracytoplasmic sperm injection (ICSI) In Vitro Fertilization (IVF) Egg production stimulated by hormone therapy (FSH, LH) Eggs retrieved from ovary Sperm sample provided Eggs and sperm combined to allow fertilization Fertilized eggs introduced into uterus (once it reaches blastocyst stage) Ovaries may become highly sensitized due to hormone therapy $10 – 15 K Intracytoplasmic sperm injection (ICSI) Sperm injected directly into oocyte Sperm not motile or some other problem Stem Cells and Cloning Totipotent cells Can be anything Zygote – 4 cell stage Pluripotent cells