Thyroid hormones (T 4 and T 3) are produced by the follicular cells of the thyroid gland and are regulated by TSH made by the thyrotropes of the anterior pituitary gland. The effects of T 4 in vivo are mediated via T 3 (T 4 is converted to T 3 in target tissues). T 3 is 3- to 5- fold more active than T 4.
May is Jewish American Heritage Month The Library of Congress, National Archives and Records Administration, National Endowment for the Humanities, National Gallery of Art, National Park Service and United States Holocaust Memorial Museum join in paying tribute to the generations of Jewish Americans who have helped form the fabric of American history, culture and society.
Updated March 03, 2017. Black History Month is a month set aside to learn, honor, and celebrate the achievements of black men and women throughout history. Since its inception, Black History Month has always been celebrated in February. Find out how Black History Month originated, why February was chosen, and what the annual theme for Black History Month is for this year.