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Organ system development
Development of the cardiovascular system
Development of the ear
Development of the eye
Development of the face and palate
Pharyngeal arches, pouches, and clefts
Development of the digestive system and body cavities
Development of the gastrointestinal system
Development of the teeth
Development of the tongue
Development of the integumentary system
Development of the axial skeleton
Development of the limbs
Development of the muscular system
Development of the nervous system
Development of the renal system
Development of the reproductive system
Development of the respiratory system
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Early in embryonic development, during the 3rd week post-fertilization, the embryo is a flat, disc-shaped organism made up of three layers of pluripotent cells called germ layers, which give rise to all the organs and tissues in the body: an inner layer, called endoderm, a central layer, called mesoderm, and an outer layer, called ectoderm.
By week 4 of development, as a result of the folding of the embryo along the rostrocaudal axis and the lateral axis, it takes on a more recognizably “human” form—but to be honest, it still looks more like a shrimp than a baby.
At the head end of this little shrimp-like creature, the neural tube expands greatly forming the primitive forebrain, which produces a bulge known as the frontal prominence.
Lateral to the neural tube is the paraxial mesoderm, which partially segments rostrally to form somitomeres and fully segments caudally to form somites, the first in the series being the occipital somites.
At this point, a small pit called the stomodeum forms between the frontal prominence and the developing cardiac bulge, and it will eventually become the oral cavity.
At the back of the stomodeum, there’s a two-layered membrane, called the buccopharyngeal membrane, made up of ectoderm and endoderm.
The buccopharyngeal membrane initially separates the stomodeum from the foregut, but soon disintegrates, allowing free access between the stomodeum and the foregut.
The development of the face and palate is a complex process that begins with the fusion of two embryological tissues, the neural crest, and the plate. The face starts to develop around week four until week 6 of prenatal life. At week six, the palate starts developing, and allows the separation between the nasal and oral cavities at around the 12th week.
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