Anatomy Chapter 1

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Anatomy Chapter 1
2012-09-13 00:09:52

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  1. What is Homeostasis
    the existance of a stable internal environment
  2. What are two general mechanisms involved in homeostatic regulation
    • Autoregulation
    • Extrinsic regulation
  3. Define Autoregulation
    occurs when a cell, a tissue, an organ, or an organ system adjusts its activites automatically in response to some environmental change
  4. An example of Autoregulation
    Whn oxygen levels decline in a tissue, the cells release chemicals that widen local blood vessles. This dilation increases the rate of blood flow and provides more oxygen to the region
  5. Define Extrinsic regulation
    results from the activites of the nervous system or endocrine system, two organ systems that control or adjust the activities of many other systems simultaneously
  6. An example of Extrinsic regulation
    When you excersize, your nervous system issues commands that increase your heart rate so that blood will circulate faster
  7. Three parts of a homeostatic regulatory mechanism
    • receptor
    • control center
    • effector
  8. What is a receptor?
    a sensor that is sensitive to a particular stimulus or environmental change
  9. What is a control center
    recieves and processes the information supplied by the receptor and sends out commands
  10. What is an effector
    a cell or organ that responds to the commands of the control center and whose activity either opposes or enhances the stimulus
  11. What is negative feedback
    a way for counteracting an effect and provides long-term control over the body's internal conditions and systems. 
  12. What is the primary mechanism of homeaostatic regulation?
    Negative feedback
  13. What is positive feedback
    an intial stimulus produces a response that exaggerates or enhances the original change in conditions rather than opposing it
  14. When are positive feedback loops typically found?
    they are typically found when a potentially dangerous or stressful process must be completed quickly before homeostasis can be restored