Gametogenesis, fertilization, hormonal cycles, pregnancy, lactation, sex determination.
Reproductive Physiology
Gametogenesis
Production of haploid gametes by meiosis + differentiation. Spermatogenesis: continuous, ~64 days, 4 sperm per precursor. Oogenesis:…
Menstrual cycle
~28-day hormonal cycle coordinating ovarian (follicular → ovulation → luteal) and endometrial phases. Driven by GnRH-FSH-LH with estrogen +…
Sex determination
Mechanisms specifying sexual phenotype. Mammals: XY chromosomal, SRY triggers testis differentiation. Birds: ZW, females heterogametic.…
Pregnancy
Gestation: implantation → placentation → fetal development → parturition. Human: ~40 weeks. Hormonal support by hCG (corpus luteum rescue),…
Lactation
Milk production + ejection by mammary epithelium. Prolactin drives synthesis; oxytocin triggers let-down via myoepithelial contraction.…
Hypothalamic-pituitary-gonadal axis
GnRH (hypothalamus) → LH/FSH (pituitary) → sex steroids (gonad). Negative + positive feedback loops. Central regulator of puberty,…
Spermatogenesis
Diploid spermatogonia → haploid spermatozoa via meiosis + spermiogenesis in seminiferous tubules. Continuous in males from puberty; ~64…
Oogenesis
Primary oocytes arrest in prophase I in utero; complete meiosis I at ovulation; meiosis II at fertilisation. Asymmetric divisions produce…
Acrosome reaction
Sperm surface Ca²⁺ influx triggers exocytosis of acrosomal hydrolases, enabling penetration of zona pellucida. Followed by membrane fusion…
Parturition (labour)
Oxytocin + prostaglandin-driven uterine contractions at term. Positive feedback: Ferguson reflex. Three stages: cervical dilation,…