1. Ch. 8 Chemical Signals – Maintaining Homeostasis The Endocrine System

2. Homeostasis What is it ?? Looked at Autonomic Nervous System Discussed Sympathetic (stress) & Parasympathetic (return) These systems work in conjunction with the Endocrine System

3. What is it ? The endocrine system is a collection of glands that secrete chemical messages we call hormones Hormone: A chemical substance secreted by a gland which provokes a response in other cells.

4. Purpose 1) Overall metabolism 2) Maintain homeostasis 3) Growth 4) Reproduction 5) Mood

5. Main Components Hypothalamus Endocrine Gland A tissue which releases (secretes) a substance (hormone) into the blood stream; this substance then travels via the blood to influence target cells A tissue which releases (secretes) a substance (hormone) into the blood stream; this substance then travels via the blood to influence target cells

6. Therefore…. The Endocrine System works together with the Nervous System to provide control over the entire body. Note: 1) NS  Adjusts quickly 2) ES  Adjusts over longer periods of time.

7. How Much ?? Only a small amount of a hormone is required to alter cell metabolism

8. Hormones Already stated that: Hormones are chemicals that are secreted into the blood stream by the endocrine glands Hormones are received by target cells throughout the body Target cells have receptor proteins that help determine the response to the hormone Different hormone/receptor combinations cause different responses

9. In The Blood Stream

10. Types of Hormones

11. Steroid Hormones Lipid soluble…means ??

12. Target Cell Creates Response

13. Structure Steroid hormones are created by modifying cholesterol molecules

14. Visualize… Steroid Hormone Video

15. Peptide and Amine Hormones Peptide and Amine hormones are large molecules that are not lipid soluble and cannot enter target cells directly. Also referred to as Protein Hormones

17. Visualize….. Peptide Hormone Peptide Hormone

18. Importance of cAMP In Peptide and Amine hormones cyclic adenosine monophosphate (cAMP) acts as a messenger. cAMP activate enzymes which continue the process. This pathway is known as the signal- transduction-pathway.

19. Practice… P. 377 Q. 1 - 4