Carnegie Stage 15: Thyroid Gland and Heart
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This section shows how the thyroid gland is formed. It is an outpouching of the ventral wall of the pharynx (back of the tongue), and retains its connection to the surface epithelium of the tongue, visible here as a teardrop shape descending from the oropharynx.
The umbilical cord supplies all nutrients and oxygen to the embryo, and is a large and important organ.
