Embryologie

Embryologie, or embryology, is the branch of biology that studies the formation, growth, and development of embryos from fertilization to birth. It integrates genetics, cell biology, physiology, and anatomy to understand how multicellular organisms develop their form and organs.

Core topics include fertilization, cleavage, gastrulation, and organogenesis. Fertilization marks the union of gametes leading to a zygote. Cleavage produces a multicellular embryo (morula, blastula). Gastrulation reorganizes cells into germ layers: ectoderm, mesoderm, and endoderm. Neurulation patterns the nervous system. Organogenesis describes the formation of organs such as the heart, limbs, and brain. Later stages cover tissue maturation and fetal development, culminating in birth in species-specific timing.

Embryologie uses comparative and experimental approaches, including the study of model organisms (mice, zebrafish, Xenopus, fruit flies) and in vitro systems such as stem cell cultures and organoids. Techniques include microscopy, lineage tracing, gene editing, and transcriptomics. Modern embryology also explores molecular pathways (signaling networks such as Wnt, FGF, and BMP) that regulate development.

History of the field includes early naturalists and embryologists who described developmental stages, with foundational concepts advanced by researchers such as Karl Ernst von Baer.

Applications and ethics address understanding congenital anomalies, improving assisted reproductive technologies, and advances in regenerative medicine and cancer research. Ethical considerations focus on embryo research, fetal tissue use, and genome editing.

See also: developmental biology, teratology, stem cell biology.