Mammalian Anatomy HW#--Endocrine

1. What structure secretes melatonin?

Pineal gland

**The pineal gland or epiphysis synthesizes and secretes melatonin, a structurally simple hormone that communicates information about environmental lighting to various parts of the body

2. Which hormone is produced by the thyroid gland?

Thyroxine

**The 2 main thyroid hormones are T3 (triiodothyronine) and T4 (thyroxine). T3 and T4 regulate your body's temperature, metabolism and heart rate. The amount of thyroid hormones secreted is controlled by another hormone, called thyroid stimulating hormone (TSH), which is released from the pituitary gland in your brain.

3. Which region of the pituitary produces melanocyte-stimulating hormone in fetuses, young children, and pregnant women?

Pars intermedia

**The melanocyte-stimulating hormones, known collectively as MSH, also known as melanotropins or intermedins, are a family of peptide hormones and neuropeptides consisting of α-melanocyte-stimulating hormone (α-MSH), β-melanocyte-stimulating hormone (β-MSH), and γ-melanocyte-stimulating hormone (γ-MSH) that are produced by cells in the intermediate lobe (pars intermedia) of the pituitary gland.

4. Which cells produce calcitonin?

C cells

**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.

5. Which cells of the pancreatic islets produce glucagon?

Alpha cells

**Alpha cells producing glucagon (20% of total islet cells)

Beta cells producing insulin and amylin (~70%)

Delta cells producing somatostatin (<10%)