Thyroid gland. Computer graphic of the thyroid gland, superimposed on the outline of a human figure. The thyroid gland (orange) is located in the neck. Here, it is seen located on the trachea (windpipe) with the larynx (voicebox) above it. The thyroid is a two-lobed gland, with the two lobes joined by an isthmus of tissue. Thyroid blood vessels are visible. As an endocrine gland, the thyroid secretes the hormones: thyroxine and calcitonin, into the blood. These hormones regulate energy levels and body metabolism, including mental and physical development. Lack of thyroid hormone may give rise to cretinism in infants and myxoedema in adults.