Introduction to Embryology PDF

WE MAKE DOCTORS INTRODUCTION TO HUMAN EMBRYOLOGY DR. GUADALUPE RODRIGUEZ EMBRYOLOGY FROM A SINGLE CELL TO A BABY IN 9 MONTHS... A developmental process that represents an amazing integration of increasingly complex phenomena. The study of these phenomena is called embryology, and th...

WE MAKE DOCTORS INTRODUCTION TO HUMAN EMBRYOLOGY DR. GUADALUPE RODRIGUEZ EMBRYOLOGY FROM A SINGLE CELL TO A BABY IN 9 MONTHS... A developmental process that represents an amazing integration of increasingly complex phenomena. The study of these phenomena is called embryology, and the field includes investigations of the molecular, cellular, and structural factors contributing to the formation of an organism.  Prenatal experiences, in combination with molecular and cellular factors, determine our potential to develop certain adult diseases, such as cancer and cardiovascular disease. Our prenatal development produces many ramifications affecting our health for both the short and long term, making the study of embryology and fetal development an important topic for all health care professionals.  HISTORY OF EMBRYOLOGY The process of progressing from a single cell through the period of establishing organ primordia (the first 8 weeks of human development) is called the period of embryogenesis (sometimes called the period of organogenesis) The period from that point on until birth is called the fetal period.  TERATOLOGY The study of the embryological origins and causes for these birth defects. These defects are principally the result of infections, physical agents, metabolic conditions or chemicals and can cause death as well as physical, behavioral, and intellectual deficits.  In 1961, the science of teratology became prominent because of the drug thalidomide that was given as an antinauseant and sedative to pregnant women. The drug caused birth defects, including unique abnormalities of the limbs in which one or more limbs was absent (amelia) or was lacking the long bones such that only a hand or foot was attached to the torso (phocomelia). PERIODS OF SUSCEPTIBILITY TO TERATOGENESIS  MOLECULAR EMBRYOLOGY  Molecular biology has opened the doors to new ways to study embryology and to enhance our understanding of normal and abnormal development. Sequencing the human genome, together with creating techniques to investigate gene regulation at many levels of complexity, has taken embryology to the next level. Molecular approaches have been added to the list of experimental paradigms used to study normal and abnormal development. Numerous means of identifying cells using reporter genes, fluorescent probes and other marking techniques have improved our ability to map cell fates. Using other techniques to alter gene expression, such as: knockout knock-in antisense technologies have created new ways to produce abnormal development and allowed the study of a single gene’s function in specific tissues. EMBRYOLOGICAL STAGES  Gametogenesis: biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes Fertilization to implantation: Fertilization is the union of the male (sperm) and female (oocyte) gametes to form a zygote and marks the beginning of pregnancy Implantation: About 6 days after fertilization, the blastocyst attaches to the lining of the uterus, usually near the top. This process, called implantation, is completed by day 9 or 10.  Bilaminar germ disc: formed when the inner cell mass forms two layers of cells, separated by an extracellular basement membrane. The external layer is called the epiblast and the internal layer is called the hypoblast Trilaminar germ disc: the conversion of the epiblast from a bilaminar disc into a trilaminar embryonic disc consisting of ectoderm, mesoderm, and endoderm. GAMETOGENESIS Turner Angelman Trisomy 13 Trisomy 18 Syndrome Syndrome BILAMINAR GERM DISC Abnormal implantation Tubal implantation TRILAMINAR GERM DISC Conjoined twins Caudal Sacrococcygeal dysgenesis teratoma REFERENCES Introduction. Embryology: Clinical Relevance and Historical Prevalence Bevis, R. (1992). Langman’s Medical Embryology, 6th edition T W Sadler Langman’s Medical Embryology, 6th Edition Williams & Wilkins 412pp £20.50 0-683-07473-8. Nursing Children and Young People, 4(3), 14. https://doi.org/10.7748/paed.4.3.14.s14 THANK YOU!