1. THYROID GLAND Tanya Shepherd Madison Reyna P.2B

2.  Located in neck, superior to the trachea  Shaped like butterfly wings.  Weighs less than an ounce  During development, it starts in the back of the tongue (lingual thyroid) and then migrates to the neck. Sometimes migrating too far and ending up in the chest. Location

3. FUNCTION & HORMONES  Produces T3 and T4 The thyroid gland needs assistance from the pituitary gland in order to produce hormones.  Thyroid cells are the only cells in the body that can absorb iodine.  Combine iodine and tyrosine to make T3 and T4 which are then released into the bloodstream to regulate the metabolism.  If the body does not receive enough iodine, it cannot produce the proper amount of hormones.

4. HORMONES CONT.  Calcitonin-regulates calcium levels within the body  Calcium is important for muscle contractions, nerve function, and blood clotting.  If we do not have enough calcium, the body will take it from the bones which will result in bone fracture, twitching, convulsions, and even death.  Too much calcium can result in weakening of muscle tone and kidney stones.

5. NEGATIVE FEEDBACK  Thyroid is part of the hypothalamic-pituitary- thyroid axis  When blood concentration of the thyroid increases, they inhibit both TRH and TSH, which shuts down the thyroid epithelial cells. When the blood concentration has decayed, the negative feedback signal fades and the system wakes up again.  Positive feedback occurs during childbirth when oxytocin stimulates labor contractions.

6. HOMEOSTASIS  Without the thyroid gland, the body would not be able to break down proteins or process carbohydrates.  This can lead to uncontrollable weight gain.  A problem within the thyroid gland can usally be fixed by prescribed medications or surgery  Hyperthyroidism – thyroid makes too much of the thyroid hormone, can cause rapid weight loss, fast heart beat, and hair loss.

7. SOURCES  http://umm.edu/programs/diabetes/health/endocrinology-health- guide/thyroid-gland http://umm.edu/programs/diabetes/health/endocrinology-health- guide/thyroid-gland  http://www.healthline.com/human-body-maps/thyroid-gland http://www.healthline.com/human-body-maps/thyroid-gland  http://www.innerbody.com/image_dige01/endo04.html#full-description http://www.innerbody.com/image_dige01/endo04.html#full-description