What It's Like To Win The Race Before You Were Born

your first win ever! 00:00 - You vs 200 million 00:15 - Phase 1: Vagina 01:43 - Phase 2: The Cervix 02:52 - Phase 3: The Uterus 03:27 - Phase 4: The Fallopian Tube 04:11 - Capacitation 05:47 - Final Phase: The Egg 07:45 - You Win! -------- SOURCES 1. SPERM COUNT & TRANSPORT NUMBERS "WHO laboratory manual for the examination and processing of human semen, 6th edition" — World Health Organization, 2021 "Sperm numbers and distribution within the human Fallopian tube around ovulation" — Human Reproduction, 1993 "Sperm selection in natural conception: what can we learn from Mother Nature to improve assisted reproduction outcomes?" — Human Reproduction Update, 2015 2. THE ACID (VAGINA) "Sperm transport in the female reproductive tract" — Human Reproduction Update, 2006 "Role of semen in modulating the female genital tract microenvironment" — American Journal of Reproductive Immunology, 2014 3. WHITE BLOOD CELLS "Sperm transport in the female reproductive tract" — Human Reproduction Update, 2006 "Sperm selection in natural conception: what can we learn from Mother Nature to improve assisted reproduction outcomes?" — Human Reproduction Update, 2015 4. CERVICAL MUCUS & CRYPTS "Sperm selection in natural conception" — Human Reproduction Update, 2015 "Selection of morphologically normal sperm in cervical mucus" — Mortimer & Templeton, 1982 5. THE HIGHWAY (UTERUS) — PASSIVE TRANSPORT "Sperm transport from the external cervical os to the Fallopian tubes in women: a time and quantitation study" — Fertility and Sterility, 1973 "The dynamics of rapid sperm transport through the female genital tract" — Human Reproduction, 1996 "Sperm transport in the female reproductive tract" — Human Reproduction Update, 2006 6. UTEROTUBAL JUNCTION (THE NARROW DOOR) "Sperm selection in natural conception" — Human Reproduction Update, 2015 "Surface protein required for sperm to cross the uterotubal junction (mouse knockouts)" — Nakanishi et al., 2004 7. THE FORK (TWO TUBES) "Sperm numbers and distribution within the human Fallopian tube around ovulation" — Human Reproduction, 1993 "The dynamics of rapid sperm transport through the female genital tract" — Human Reproduction, 1996 8. THE WAITING ROOM (ISTHMUS) — CAPACITATION & FERTILE WINDOW "Sperm capacitation in humans is transient and correlates with chemotactic responsiveness to follicular factors" — PNAS, 1995 "Timing of sexual intercourse in relation to ovulation" — New England Journal of Medicine, 1995 "Sperm selection in natural conception" — Human Reproduction Update, 2015 9. FINAL GUIDANCE (RHEOTAXIS, CHEMOTAXIS, THERMOTAXIS) "Rheotaxis guides mammalian sperm" — Current Biology, 2013 "Thermotaxis of mammalian sperm cells: a potential navigation mechanism in the female genital tract" — Nature Medicine, 2003 "Sperm capacitation in humans is transient and correlates with chemotactic responsiveness to follicular factors" — PNAS, 1995 "Chemical signals from eggs facilitate cryptic female choice in humans" — Proceedings of the Royal Society B, 2020 10. THE WALL (CUMULUS + ZONA PELLUCIDA) "Most fertilizing mouse spermatozoa begin their acrosome reaction before contact with the zona pellucida during in vitro fertilization" — PNAS, 2011 "Site of the mammalian sperm physiological acrosome reaction" — PNAS, 2011 "Acrosin is essential for sperm penetration through the zona pellucida in hamsters" — PNAS, 2020 11. BLOCK TO POLYSPERMY "Preventing polyspermy in mammalian eggs — Contributions of the membrane block and other mechanisms" — Molecular Reproduction and Development, 2020 "Ovastacin, a cortical granule protease, cleaves ZP2 in the zona pellucida to prevent polyspermy" — Journal of Cell Biology, 2012 12. PATERNAL MITOCHONDRIA "Ubiquitin tag for sperm mitochondria" — Nature, 1999 "Postfertilization autophagy of sperm organelles prevents paternal mitochondrial DNA transmission" — Science, 2011 "Elimination of paternal mitochondria in mouse embryos occurs through autophagic degradation dependent on PARKIN and MUL1" — eLife, 2016 "Autophagy and ubiquitin–proteasome system contribute to sperm mitophagy after mammalian fertilization" — PNAS, 2016 13. SPERM PRODUCTION & MYTHS "Daily spermatozoal production and epididymal spermatozoal reserves of the human male" — Journal of Urology, 1980 "No evidence for killer sperm or other selective interactions between human spermatozoa in ejaculates of different males in vitro" — Proceedings of the Royal Society B, 1999