Overview of Human Embryologic Development PDF

BIO10004 – Anatomy and Physiology Overview of Human Embryologic Development Dr Greg Davis  WARNING This material has been reproduced and communicated to you by or on behalf of Swinburne University of Technology in accordance with Section 113P of the Co...

BIO10004 – Anatomy and Physiology Overview of Human Embryologic Development Dr Greg Davis  WARNING This material has been reproduced and communicated to you by or on behalf of Swinburne University of Technology in accordance with Section 113P of the Copyright Act 1968 (the Act). The material in this communication may be subject to copyright under the Act. Any further reproduction or communication of this material by you may be the subject of copyright protection under the Act. Learning objectives and reading At the end of this lecture, you should be able to: 1. Describe the major stages and events of gestation 2. Understand the process of fertilisation 3. Describe the major stages of prenatal development Reading guide (textbook): Fundamentals of Anatomy & Physiology, Martini et al., Eleventh Edition, Chapters 29 Human Embryonic Development Fundamentals of Anatomy and Physiology 2020; 11th Edition Gestation Time spent in prenatal development § First trimester Pre-embryonic through early fetal development Rudiments of all major organ systems appear § Second trimester Development of organs and organ systems Body shape and proportions change § Third trimester Rapid fetal growth and deposition of adipose tissue Most major organ systems are fully functional Fundamentals of Anatomy and Physiology 2020; 11th Edition  Fertilization Oocyte at Ovulation Ovulation releases a secondary oocyte and the first polar body; both are 1 Fertilization and Oocyte Activation Acrosomal enzymes from multiple sperm create gaps in the corona 2 Pronuclei Develop and DNA Synthesis Occurs The sperm is absorbed into surrounded by the corona radiata. The radiata. A single sperm then makes the cytoplasm, and the female oocyte is suspended in metaphase of contact with the oocyte membrane, pronucleus develops. As the meiosis II. and membrane fusion occurs, male pronucleus develops, triggering oocyte activation and the most remaining sperm break completion of meiosis. down. Corona First polar radiata body Second polar Nucleus of Female Fertilizing body fertilizing pronucleus sperm sperm Zona pellucida First Cleavage Forms 5 Two Blastomeres 4 Amphimixis Occurs and Cleavage Begins 3 Spindle Formation Begins The first cleavage division nears Pronuclei chromatin condenses completion about 30 hours after into chromosomes, and spindle fertilization. fibers appear in preparation for the Maternal and paternal first cell division. chromosomes align on metaphase plate Centrioles Female pronucleus Male pronucleus Blastomeres Fundamentals of Anatomy and Physiology 2020; 11th Edition  Gestation - First trimester First trimester involves four general processes Cleavage Implantation Placentation Embryogenesis Fundamentals of Anatomy and Physiology 2020; 11th Edition  Gestation First trimester involves four general processes Cleavage Implantation (Occurs 7–10 days after fertilization) Placentation Embryogenesis Fundamentals of Anatomy and Physiology 2020; 11th Edition  Implantation 7–10 days after fertilization Blastocyst adheres to uterine lining Trophoblast cells divide rapidly, creating layers Fundamentals of Anatomy and Physiology 2020; 11th Edition  Placentation and Embryogenesis Placentation: Occurs as blood vessels form around periphery of blastocyst Placenta develops to permit exchange between maternal and embryonic blood Embryogenesis: Formation of viable embryo Establishes foundations for all major organ systems Fundamentals of Anatomy and Physiology 2020; 11th Edition  Gestation – Second and Third trimester Second trimester Fetus grows faster than surrounding placenta Third trimester Most organ systems become able to function without maternal assistance Growth rate slows but much weight is gained Fetus and enlarged uterus displace many of mother’s abdominal organs Fundamentals of Anatomy and Physiology 2020; 11th Edition  Prenatal development Fundamentals of Anatomy and Physiology 2020; 11th Edition  Growth of the Uterus and Fetus during Gestation Fundamentals of Anatomy and Physiology 2020; 11th Edition Maternal Changes Fetus is wholly dependent on maternal organs Increases seen in: – Respiratory rate – Tidal volume – Blood volume – Nutrient and vitamin intake – Kidney filtration rate Thank you!