Homeostasis and Regulation

1. Homeostasis and Regulation Student Expectation (SE) 10A – describethe interactions that occur among systems that perform the functions of regulation Student Expectation (SE) 11A - describethe role of internal feedback mechanismsin the maintenance of homeostasis

2. Homeostasis Homeostasis– stable internal conditions required for body systems to function The body must constantly regulate vital body conditions within an acceptable range in order to preserve homeostasis

3. 2. Homeostasis in the Body includes: b. Blood Sugar a. Temperature:

4. 2. Homeostasis in the Body includes: d. Respiratory Rate c. Heart Rate:

5. 2. Homeostasis in the Body includes: f. Oxygen Concentration e. Blood Pressure:

6. 3. Which body systems work together to maintain homeostasis? NERVOUS SYSTEM ENDOCRINE SYSTEM • Detects the changes in the body • Communicates • the changes via hormones ALL body systems must maintain homeostasis but it is mainly controlled by:

7. 4. How does homeostasis work? Negative Feedback • Reduces the output of a system • Two mechanisms with opposite effects • Also called Feedback Inhibition The Nervous and Endocrine Systems work through Negative and Positive Feedback.

8. 5. Body Temperature How it works: Skin and brain monitor temperature Temperature too high  brain signals skin’s sweat glands to cool body; heat can also be dissipated by dilating capillaries (circulatory) in the skin Temperature too low,  brain signals muscles (muscular) to contract; temperature can also be raised by pooling blood to the internal organs Organ systems involved: integumentary, nervous, circulatory and muscular

9. Heart and Respiratory rates Organ Systems Involved: circulatory, respiratory, and nervous How it Works: Receptors of the nervous system monitor blood pressure and oxygen levels If too high, heart or lungs decrease rate If too low, heart or lungs increase rate

10. Blood Concentrations Organ Systems Involved: endocrine, nervous, excretory, integumentary, digestive, and circulatory How it works: 1. Brain signals endocrine glands to produce hormones, which travel through blood. 2. Kidneyssignal to release more or less water as needed 3. Skin can sweat to lower water levels 4. Liver releases glucose and pancreas releases insulin to change sugar levels in blood

11. Glucose Level Regulation

12. Positive Feedback A process that increases the output of a system. Examples: blood clotting child birth Lactation menstration

13. 7. Positive Feedback in Childbirth Stimulus: Contractions Response: Hypothalmaus secretes oxytocin Result: Contractions

14. Sample STAAR Question ACTH Increases Stimulus: ____________ A dog’s pituitary gland produces the hormone ACTH, which stimulates the adrenal glands  to secrete cortisol. Cortisol helps regulate body weight, mineral balance, the structure of  connective tissue, the production of white blood cells, and skin health. When cortisol levels  are low, the pituitary gland secretes ACTH. When cortisol levels are high, the pituitary gland  stops secreting ACTH. Based on this information, which of the following would most likely be the cause of elevated levels of cortisol in a dog? A Undersized adrenal glands B An excess of ACTH C An inactive pituitary gland D An immune response to the excess level of cortisol Response:____________ Adrenal Glands activate Result: ____________ Cortisol Increases