1. HYPOTHALAMUS AND PITUITARY

2. Hypothalamus and Pituitary

3. THYROID HORMONES

4. Thyroid Gland Located in front of the throat Shaped like a bow tie, or butterfly Secretes thyroxine (T 4 ) and triiodothyronine (T 3 )

5. Thyroid Hormones Thyroxine (T 4 )Triiodothyronine (T 3 ) Where do you get your iodine? Can you spot the difference?

6. TRH TSH T4T4 Thyroid hormone feedback loop 1.TRH released by hypothalamus, stimules release of TSH in pituitary 2.TSH stimulates thyroid, inhibits release of TRH 3.Thyroxine (T 4 ) from thyroid inhibits release of TSH What happens if you don’t get enough iodine?

7. TRH TSH T4T4 Iodine deficient goiter 1.TRH released by hypothalamus, stimules release of TSH in pituitary 2.TSH stimulates thyroid, inhibits release of TRH 3.Thyroxine (T 4 ) from thyroid inhibits release of TSH 4.Lack of iodine prevents T4 formation, loss of negative feedback on TSH 5.TSH continues to stimulate thyroid

8. Iodine Deficient Goiter

9. Calcitonin Thyroid gland also produces calcitonin, which is involved in calcium balance Calcitonin is released in response to rising blood Ca 2+ levels

10. PARATHYROID HORMONES

11. Parathyroid Glands 4 small glands on posterior side of thyroid gland Produce parathyroid hormone (PTH) Involved in calcium balance Released in response to low blood Ca 2+ levels

13. PINEAL GLAND

14. Pineal Gland Regulates several biological rhythms Secretes melatonin When eyes see light, melatonin secretion is inhibited

15. LED Screens and Melatonin What affect do you think LED screens on phones and tablets have on melatonin levels in the brain?