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.
The hormone calcitonin, which is produced by the parafollicular (or C) cells of the thyroid, has the opposite effect on blood calcium levels as PTH. Calcitonin decreases blood calcium levels by inhibiting osteoclasts, stimulating osteoblasts, and stimulating calcium excretion by the kidneys.