BIO 265 – Human A&P

1. BIO 265 – Human A&P Chapter 16 – Part B - Endocrine Glands

2. Intro. To Endocrine Glands • Figure 16.1

3. Pituitary Gland and Hypothalamus • The pituitary gland secretes 9 major hormones that regulate numerous body functions • The hypothalamus regulates the secretory activity of the pituitary gland • Important structures: • Infundibulum • Posterior pituitary (composed of nervous tissue) • Anterior pituitary (true gland tissue) • Figures from other text

4. Pituitary Gland and Hypothalamus • Regulation of hormone secretion • Anterior pituitary • The hypothalamus secretes releasing or inhibiting hormones • Figure from other text

5. Pituitary Gland and Hypothalamus • Posterior pituitary (neurohormones) – Figure

6. Pituitary Gland and Hypothalamus • Hormones of the Pituitary Gland • Table 16.1

7. Pituitary Gland and Hypothalamus • Hormones of the Anterior Pituitary • Some of these are tropic hormones that regulate the secretion of hormones from other glands • Gonadotropins – control the production of sex hormones as well as gametes • Luteinizing hormone (LH) and Follicle stimulating hormone (FSH) • Regulation by gonadotropin releasing hormone (GnRH) – Figure 18.3 • More in chapter 28.

8. Pituitary Gland and Hypothalamus • Growth hormone (GH) – stimulates growth in most tissues and regulates metabolism • stimulates the breakdown of fats in adipose tissue • Secretion is stimulated by stress and low blood glucose levels • Figure 18.6

9. Pituitary Gland and Hypothalamus • Thyroid stimulating hormone (TSH) • others

10. Thyroid Gland • Location in the body – Figures 16.1 and 16.7

11. Thyroid Gland • Hormones: • Calcitonin – what does this do? • Thyroid Hormones - Triiodothyronine (T3) and thyroxine (T4) • These interact with intracellular receptors • They affect metabolism and growth of tissues • Regulation of secretion – Figure and CD animation

12. Parathyroid Glands • Secretes Parathyroid Hormone (PTH) • What does this hormone do? • Bone – increased osteoclast activity • Kidney – increased reabsorption of calcium and production of Vit. D • Intestines –increases calcium uptake • Figure 16.11 and CD animation

13. Adrenal Glands • Location – Figure 16.1 and 16.12

14. Adrenal Glands • Composed of an inner medulla and an outer cortex • The adrenal cortex produces aldosterone • This increases sodium reabsoption in the kidneys • which increases water reabsorption and therefore blood volume • How would this hormone be related to ADH?

15. Adrenal Glands • The adrenal medulla produces epinephrine (adrenalin) and norepinephrine (noradrenalin) • These hormones bind to adrenergic receptors that function through G-protein systems • Regulation and functions – Figure 16.15

16. The Pancreas • The pancreas is both an endocrine gland and an exocrine gland • Exocrine – acini (digestive enzymes) • Endocrine – pancreatic islets (islets of Langerhans) • Figure 16.1

17. Pancreas • Effect of glucagon • Affects the liver • It increases glycogen breakdown and glucose synthesis and secretion • When would glucagon be released?

18. Pancreas • Effect of insulin • Target tissues: liver, adipose tissue, and skeletal muscle • Binds to a membrane-bound receptor and increases glucose uptake • Glucose is then converted to glycogen in muscle and liver cells and fat in adipose cells • Without insulin adipose tissue and skeletal muscle take up and use very little glucose and amino acids

19. Pancreas • Regulation of insulin secretion? • Figure 16.17 and CD animation

20. Pancreas • Diabetes mellitus • Type 1 or insulin-dependent diabetes mellitus • Caused by the autoimmune destruction of pancreatic islets • Only 3% of total diabetes cases • Usually seen in young people • Type 2 Diabetes (insulin independent or adult-onset diabetes) • Results from the inability of tissues to respond to insulin • Cause is unknown (genetic?)

21. Pancreas • It is sometimes referred to as insulin resistance • 97% of total diabetes cases

22. Reading • Reading Sections in Chapter 16