Langman’s Medical Embryology covers embryology for medical, nursing, and health professions students with a strong clinical emphasis. The text is highly valued as a teaching and learning resource for its clinical correlation boxes, summaries, problems to solve, illustrations and clinical images, and clear, concise writing style—all of which make the subject matter accessible to students and relevant to instructors. Online material includes Simbryo—an animation program showing processes, organs, and systems developing in human embryos—as well as review questions and full text online. A separate Faculty Image Bank and PowerPoint presentations are also available
Embryology (from Greek ἔμβρυον, embryon, “the unborn, embryo“; and -λογία, -logia) is the branch of biology that studies the prenatal development of gametes (sex cells), fertilization, and development of embryos and fetuses. Additionally, embryology encompasses the study of congenital disorders that occur before birth, known as teratology
Embryology is the study of development of an embryo from the stage of ovum fertilization through to the fetal stage.
The ball of dividing cells that results after fertilization is termed an “embryo” for eight weeks and from nine weeks after fertilization, the term used is “fetus.
Outline of conception
Once an egg is released from the ovary during ovulation, it meets with a sperm cell that was carried to it via the semen. These two gametes combine to form a zygote and this process is called fertilization. The zygote then begins to divide and becomes a blastula.
The blastula develops in one of two ways, which actually divides the whole animal kingdom in half. The blastula develops a pore at one end, called a blastopore. If that blastopore becomes the mouth of the animal, the animal is a protostome, and if it forms an anus, the animal is a deuterostome.
Protosomes are invertebrate animals such as worms, insects and molluscs while deuterostomes are vertebrates such as birds, reptiles, and humans.
The blastula continues to develop, eventually forming a structure called the gastrula. The gastrula then forms three germ cell layers, from which all of the body’s organs and tissues are eventually derived. From the innermost layer or endoderm, the digestive organs, lungs and bladder develop; the skeleton, blood vessels and muscles are derived from the middle layer or mesoderm and the outer layer or ectoderm gives rise to the nervous system, skin and hair.
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