There are three muscles located in the anterior compartment of the upper arm â biceps brachii, coracobrachialis and brachialis. They are all innervated by the musculocutaneous nerve. A good memory aid for this is BBC â biceps, brachialis, coracobrachialis.
Calcitonin is a hormone secreted by the thyroid gland that reduces the concentration of blood calcium level when it has risen to an above normal level. This polypeptide hormone is made up of 32 amino acids and is produced mainly by the parafollicular cells (also known as C cells) of the thyroid gland.
An increase in blood calcium stimulates calcitonin, a hormone synthesized in the thyroid gland. This hormone lowers blood calcium by inhibiting bone resorption. Calcitonin's physiological function as a regulator of blood calcium levels is relatively minor compared to the actions of PTH and calcitriol.