A normal adult thyroid gland weighs 10 to 20 g and receives blood from bilateral superior and inferior thyroid arteries and a small artery called the thyroid ima. The thyroid secretes two hormones. Thyroxine (T 4) makes about 90% of hormone production, and triiodothyronine (T 3) produces the other 10%.
Fast Growing Cold Hardy Tree. - Grows up to 5 ft per year! The Quaking Aspen is well known for thriving in cold climates and poor soil... but it's also a brightly colored tree with many desirable characteristics.
In good situations, aspen can reach a height of twenty metres, but in most locations in the Highlands it will only grow to about ten metres tall. The bark is grey, or sometimes greenish-grey, and is either smooth or in some cases is pitted with diamond-shaped lenticels.