1. Endocrine System Chapter 8

2. Overview of Hormones The endocrine and nervous systems often work together to bring about homeostasis. The blood stream transports hormones throughout the body.

3. Overview of Hormones Each hormone acts on a certain type of tissue called its target tissue. Organs, tissues, or cells lacking the specific receptor do not respond to its stimulating effects.

4. Negative Feedback Loop A decrease in function in response to a stimulus The system controls how much product it makes by shutting down manufacturing when levels of output or the amount of accumulated product gets too high  Example # 1: the regulation of the blood glucose level in the body  Example # 2: regulation of body temperature

5. Negative Feedback Loop

6. Positive Feedback Loop An increase in function in response to a stimulus “A” produces more of “B” which in turn produces more of “A” Only a few positive feedback loops occur in the human endocrine system.  Example: the process of birthing a child

7. Positive Feedback Loop

8. Glands

9. Exocrine glands – secretions released into ducts opening onto an epithelial surface Endocrine glands – ductless organs that secrete their molecules directly into the bloodstream

10. Glands Endocrine glands are activated by other hormones

11. Hypothalamus Controls the pituitary gland Receives information from the nervous system

12. Pituitary Location: Inferior to the hypothalamus Known as the master gland

13. I. Anterior Pituitary 1. Growth hormone (GH)  General metabolic hormone  Major effects are directed to growth of skeletal muscles and long bones

14. I. Anterior Pituitary 2. Prolactin (PRL)  Stimulates and maintains milk production following childbirth  Function in males is unknown

15. I. Anterior Pituitary 3. Adrenocorticotropic hormone (ACTH)  Regulates endocrine activity of the adrenal cortex which makes a hormone called cortisol (helps the body manage stress)

16. I. Anterior Pituitary 4. Thyroid-stimulating hormone (TSH)  Produces the hormone thyroxine Regulates the rate of metabolism

17. I. Anterior Pituitary Gonadotropic hormones – Regulate hormonal activity of the gonads  5. Follicle-stimulating hormone (FSH) Stimulates follicle development in ovaries Stimulates sperm development in testes

18. I. Anterior Pituitary Gonadotropic hormones – Regulate hormonal activity of the gonads  6. Luteinizing hormone (LH) Triggers ovulation Prepares uterus for fertilized egg Stimulates testosterone production in males

19. II. Posterior Pituitary 1. Oxytocin  Stimulates contractions of the uterus during labor  Causes milk ejection

20. II. Posterior Pituitary 2. Antidiuretic hormone (ADH)  Can inhibit urine production  In large amounts, causes vasoconstriction leading to increased blood pressure

22. Posterior PituitaryAnterior Pituitary

23. Mnemonic Device for anterior and posterior pituitary gland  Anterior pituitary FLAT PIG  FSH  LH  ACTH  TSH  Prolactin  (Ignore)  Growth Hormone  Posterior pituitary Audio Osmosis = AO = ADH and Oxytocin

24. Mnemonic Device HormoneTargeted AreaProduces FFSHOvaries and Testes Sperm and egg LLHOvaries and Testes Ovulation and testosterone AATCHAdrenal GlandCortisol TTSHThyroidThryoxine PProlactinBreastMilk IIgnore-- GGHGHMuscles and bones Growth of muscles and bones Anterior Pituitary Gland Chart

25. Mnemonic Device HormoneTargeted AreaProduces AADHKidneysInhibit urine production OOxytocinUterus and breastUterine contraction and milk letdown Posterior Pituitary Gland Chart