1. Henry Tanner: 1900’s – “Angels and Shepherds”

2. The Endocrine System Chapter 10: 257-265 276-278

3. Hormones and Homeostasis…Of Course! “Homeostasis depends on the precise regulation of the organs and organ systems of the body. The Nervous and Endocrine Systems are the two major systems responsible for that regulation.”

4. Nervous v s. Endocrine Axons relay the message directly to target Fast/Short Acting Homeostatic “Rescue” Blood delivers message to widespread targets Slow/Long Lasting Adaptation – Training Effect

5. Chemical Signals (Ligands): Autocrine: Released from one type of cell – targets the same type of cell Prostaglandins - inflammation Paracrine: Released from one cell – targets a neighboring cell without being transported in the blood Nitric Oxide in blood vessels

6. More Ligands: Endocrine: released into the blood for distant target tissues Insulin: Pancreas – Muscle Neurohormones: Released by nerves into the blood Antidiuretic Hormone (ADH): Posterior Pituitary - Kidney

7. Last But Not Least… Neuromodulators: Released by nerves to modulate the activity of neighboring nerves Neurotransmitters: Released by nerves to signal activity in neighboring nerves / tissues Pheromones: Released into the air to attract mates…

8. Let’s Look Closely… Page 258: Examples of Chemical Signals

9. At The Target Cell: Intracellular Recepters: Ligand able to diffuse into cell – receptor in cytosol (enzymes) or nucleus (DNA – RNA synthesis) Membrane Bound Receptors: Ligand activates receptor – initiate intracellular responses

10. Responses: Channels open/close Acetylcholine – Na+ Channels Enzymes Activated Glycogenolysis enzymes G-Proteins Initiated Activate chemical signals: cAMP DNA/RNA synthesis

11. A Closer Look at Blood Glucose Homeostasis : Who Cares (About Blood Glucose)? The Brain Does (45% of all Glucose used by the brain) What are Normal Fasting Levels? 70-100 mg/dl blood What are Normal Fed Levels? 120-180 mg/dl

12. Glucose Muscle 10% BRAIN 45% Glycolysis 20% (RBC) Other 25% Food Gluconeogenesis Glycogenolysis

13. Hypoglycemia: A Homeostatic Emergency! Eat! Make New Glucose: Gluconeogenesis Break Down Stored Glycogen: Glycogenolysis

14. Sustaining the Fast: (Non- Feed Options) Glucagon: A Pancreatic Hormone that acts on liver cells: Glycogenolysis, Gluconeogenesis, Lipolysis Glucocorticoids: Adrenal medulla hormone that acts on liver, fat, muscle cells: Lipolysis, Gluconeogenesis

15. Fasting and Insulin: Fasting Hypoglycemia Hypoglycemia Glucagon and Glucocorticoids INSULIN Hypoglycemia Glucagon Glucocorticoids

16. Response to Starvation Decrease Insulin: Conserves Glucose for the brain Increase Glucagon/Glucocorticoids: Mobilizes stored glycogen/fats to maintain energy and glucose NET EFFECT: Stable Blood glucose for the BRAIN

17. INSULIN GLUCAGON Hormones During Fasting

18. After Feeding (Twinkies?) Increased Blood Glucose Pancreas Secretes Insulin Inhibits: Glucagon and Glucocorticoids NET EFFECT: Increase glucose uptake by muscles and fat cells for use and storage

19. INSULIN GLUCAGON Hormones after Feeding

20. One Last Exercise Application: Muscles Need Lots of Fuel Glucose is Important in Brief Intense Exercise We don’t Feed During Exercise

21. Exercise is a Homeostatic Emergency! Sympathetic Nervous System Activated! Decreases Insulin Increases “Mobilizing Hormones: Glycogenolysis, Gluconeogenesis Stimulated

22. But Wait! How does Glucose get into the muscles??? EXERCISE stimulates Glucose Transporters and Glucose Uptake Without Insulin!

23. Which Means: Glucose can get into muscle cells Glucagon/Glucocorticoids can maintain glucose mobilization and supply We don’t need to eat while we work!

24. Exercise and Diabetes NIDDM: Regular activity improves the “receptor problem” May be the most important treatment (prevention?) for NIDDM!! IDDM: Exercise reduces the amount of insulin needed: May pose the risk of hypoglycemia

25. This wraps up our semester long journey It’s been FUN!