The primary function of the thyroid is the production of the iodine-containing thyroid hormones, triiodothyronine (T3) and thyroxine (T4) and the peptide hormone calcitonin. 1  T3 is so named because it contains three atoms of iodine per molecule and T4 contains four atoms of iodine per molecule.
Explorations of Africa. In the official role of a medical missionary, he set forth to Africa, arriving in Cape Town, South Africa in March of 1841. A few years later, he married Mary Moffat; the couple would have several children.
1505 â LourenÃ§o de Almeida made the first Portuguese voyage to Ceylon and established a settlement there. 1506 â TristÃ£o da Cunha discovered the island that bears his name. Portuguese sailors become the first Europeans to reach Madagascar. 1509 â The Bay of Bengal crossed by Diogo Lopes de Sequeira.