Introduction & Homeostasis Dr. Kyle Coffey

1. Introduction & HomeostasisDr. Kyle Coffey Week 1

2. Syllabus & Course Review • Highlights of Syllabus • Please review in detail on your own time. • Ask me any questions. • Office Hours: see syllabus for posted hours • Can be by appointment if need be • Exam schedule

3. Homeostasis • Control of internal environment • Dynamic • Hovers around a set value, i.e. optimal value • Causes: disease, exercise • Not synonymous with steady-state • Overall goal of body during rest and exercise is to regulate physiological variables around a constant value Give me one example of homeostatic and a steady-state condition:

4. Control Systems • Interconnected components that maintain a chemical or physical parameter • Stimulus • Sensor • Control center • Effectors

5. Control Systems Control center Data to control center Response to Stimulus Sensor Effect Change of internal conditions Negative feedback/return to normal Stimulus Too much/too little HOMEOSTASIS

6. Types of Control Systems • Negative Feedback • Most common in body • Results in decrease in original stimulus • Response is opposite to the stimulus • Positive Feedback • Less common but present • Increase original stimulus

7. Gain • Precision in which a control system maintains homeostasis • Large and low gain • Large: more important system (cardiopulmonary, circulation)

8. Exercise & Effect on Homeostasis • Depends on many factors • Degree of exercise • Activity level of an individual • Environmental variables • Adaptation • Change in the structure or function of a cell/organ system in response to improving its ability to maintaining homeostasis • Acclimation • Improved function of an existing system

9. Adaptation & Acclimation • Occurs from cell signaling • Intracrine • Juxtacrine • Autocrine • Paracrine • Endocrine