Maintenance of Life

Question 1

Requirements of Organisms

Answer 1

• Life depends on the availability of Water, Food, Oxygen, Heat, Pressure
• Both the quality and quantity of these factors are important.

Question 2

Maintenence of a stable internal environment is called [ homeostasis ]

Answer 2

• Receptors are of many types whose job is to monitor for changes.
• The set point is the normal value or range of values.
• Effectors are muscles or glands that respond to the changes to return to stability.
• Many of the body’s homeostatic controls are negative feedback mechanisms.
  
  • Responses move in the opposite direction from the change.
  • Reduces the amount of change from the set point.
  • Includes most control mechanisms in the body.
• Positive feedback mechanisms.
  
  • Response moves further from the set point.
  • Change from set point gets larger.
  • Many positve feedback mechanisms produce unstable conditions in the body. (Clotting and contractions during birth.)