Reproductive System: From Puberty to Fertilization and Pregnancy - Prof. Douglas N. Ishii, Study notes of Biology

Download Reproductive System: From Puberty to Fertilization and Pregnancy - Prof. Douglas N. Ishii and more Study notes Biology in PDF only on Docsity! 13 April Objectives Explain/understand what puberty is Explain the process leading up to fertilization Explain the processes underlying fertilization Understand early embryo development and maternal recognition Understand the signaling between fetus and mom Explain parturition and lactation Puberty Hypothalamic-pituitary-gonad axis pretty inactive pre puberty Sex steroids: low prepuberty, unchanged at onset of puberty, then adult level Feedback: operative and sensitive → decreasing in sensitivity → operative at adult level Gonadotropins: low → increasing → adult level kisspeptin protein Derived from kiss1 gene Gene is turned on by estrogens Girls require ~17% body fat to start puberty Minimum amount of body fat must be maintained for regular cycles Leptin related Egg viable after ovulation for 24 – 48 hours Average sperm production – 300 million/day Viable for 72 hours Average 180 million/ejaculation (~3 mL) Fertilization occurs in fallopian tube Female reproductive tract is acidic Cervix is barrier due to mucus Have to choose correct fallopian tube Utero-tubal junction - ~100-1000 sperm reach this point Reach egg - ~20-200 sperm Fertilization Capacitation Final maturation of sperm Occurs in the female reproductive tract Increase in membrane fluidity Increase in motility Hyperactivation Bind to zona pellucida Acrosome reaction Membrane of acrosome and sperm membrane fuse Enzymes from acrosome released Eats through cells to reach oocyte