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.
David Livingstone was born on March 19, 1813, in Blantyre, South Lanarkshire, Scotland, and grew up with several siblings in a single tenement room.
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.