Embryology Notes
Zebrafish Development The teleost fish Danio rerio is commonly known as the zebrafish. It is a common small‐bodied tropical, freshwater species originally from South Asia. The fish is a part of the Cyprinidae family, which includes carps, true minnows, barbs and related genera. The Danio genus (formerly Brachydanio) contains more than 40 related species along with the zebrafish (Danio … Read more Zebrafish Development
Implantation- Process, Events, Significance The term “implantation” is used to describe the process of attachment and invasion of the uterus endometrium by the blastocyst (conceptus) in placental animals. It begins at the end of the first week and is completed by the end of the second week of gestation. Implantation occurs in the endometrium of … Read more Implantation- Process, Events, Significance
Heart Embryology- Development of the Heart The heart is a muscular organ located in the middle mediastinum that pumps blood through the circulatory system. It is one of the earliest differentiating and functioning organs in the human body. In human embryos, the heart begins to beat at about 22-23 days, with blood flow beginning in the 4th … Read more Heart Embryology- Development of the Heart
What is Developmental Biology? It is the field of biology that studies the processes by which multicellular organisms grow and develop, controlled by their genes. It involves the study of mechanisms of development, differentiation, and growth in animals and plants at the molecular, cellular, genetic and evolutionary levels. It also encompasses the biology of regeneration, asexual reproduction, metamorphosis, and the growth and differentiation … Read more Developmental Biology
Stem cells refer to such cells that can differentiate into other types of cells and can also divide in self-renewal to produce more of the same type of same cells. The earliest stem cells in the human body are those found in the human embryo. The stem cells inside an embryo will eventually give rise … Read more Stem Cells- Sources, Characteristics, Types, Uses
Stages of Childbirth Labor is a physiologic process during which the fetus, its associated membranes, the umbilical cord, and the placenta are expelled from the uterus. During most of the months of pregnancy, the uterus undergoes periodic episodes of weak and slow rhythmical contractions called Braxton Hicks contractions. Contractions become progressively stronger toward the end … Read more Stages of Childbirth
Drosophila Development- Stages, Significance The fruit fly Drosophila melanogaster has been extensively studied for over a century as a model organism for genetic investigations. It also has many characteristics that make it an ideal organism for the study of animal development and behavior, neurobiology, and human genetic diseases and conditions. Image Source: biology.kenyon.edu Developmental Stages of Drosophila The … Read more Drosophila Development- Stages, Significance
The nematode worm Caenorhabditis elegans is a small (1 mm long), unsegmented, vermiform, free-living soil nematode. It is a relatively simple, and precisely structured organism, extensively used as a model organism for molecular and developmental biology. The body of an adult C. elegans hermaphrodite contains exactly 959 somatic cells, whose entire lineage has been traced through its … Read more Development of Caenorhabditis elegans
The preimplantation period of human embryo development is remarkable and characterized by successive changes in terms of genetic control, physiology, and morphology of the embryo. Blastocyst (Greek, blastos= sprout + cystos = cavity) is a distinctive stage of mammalian embryo development, characterized by a hollow cellular mass that forms in early development. It is an embryo that has developed for … Read more Blastocyst- Stages, Significance
DNA methylation is a process by which methyl groups are added to the DNA molecule. It is an epigenetic mechanism that occurs by the addition of a methyl (-CH3) group to DNA, thereby often modifying the function of the genes and affecting gene expression. The most widely characterized DNA methylation process is the covalent addition of the methyl group at the 5-carbon of … Read more DNA Methylation
‘Embryo transfer’ refers to the transplantation of a mammalian preimplantation embryo into the reproductive tract of a recipient female so that it may implant and continue to develop to birth. Mammalian embryos of many species can develop in vitro from fertilization to the blastocyst stage (approximately 100 cells), but at this point, they must implant in the … Read more Human Embryo Transfer
Human Embryogenesis Human embryogenesis refers to the development and formation of the human embryo. It encompasses the first eight weeks of development after fertilization, in which a single cell formed at fertilization turns into an organism with a multi-level body plan. It is characterized by the process of cell division and cellular differentiation that occurs during the early stages … Read more Human Embryogenesis
The most characteristic event occurring during the third week of gestation is gastrulation. Gastrulation is a formative process by which the three germ layers, which are precursors of all embryonic tissues, and the axial orientation are established in embryos. During gastrulation, the bilaminar embryonic disc is converted into a trilaminar embryonic disc. Extensive cell shape … Read more Gastrulation- Process, Consequences
