homeostasis and response

• What is homeostasis?

  Maintaining a stable internal environment despite changing conditions 
• Why does the body need to maintain optimal conditions?

  For optimal enzyme action and cell function
• what are considered 'internal conditions'?

  Blood pH

  Blood glucose concentration 
• True or false? Homeostasis ensure internal conditions stay exactly constant, they don't fluctuate at all. 

  False
• what are considered 'external conditions'?

  • The amount of fluids you drink
  • Room temperature 
• Homeostasis relies on automatic control systems. 

  In what order are signals passed along the control system? 

  receptor ➔ coordination centre ➔ effector
• What is the role of a receptor? 

  Detects changes in the internal or external environment 
• What is the role of a coordination centre? 

  Interprets changes and organises a response 
• Where are the coordination centres located in the body?

  • brain
  • spinal cord
• Name the two types of effectors and state what they do.

  
  

  
  

  The two types of effectors are muscles and glands. 

  Muscles contract when stimulated, whilst glands release hormones. 
• Is the nervous system or the endocrine system faster acting?

  The nervous system is much faster acting as it relies on electrical impulses that can travel very quickly. 
• Which system acts more generally across the body, the nervous system or the endocrine system? 

  The endocrine system acts more generally as it involves releasing hormones into the blood stream which means they spread throughout the entire body. 
• Homeostasis relies on a system of negative feedback, meaning whenever the levels of something get too high they're brought back down, and whenever the levels of something get too low, they're brought back up. 
• If our body temperature gets too high, negative feedback will cause our temperature to:

  Decrease back down

  Negative feedback always involves reversing a change. So if the body temperature gets too high, negative feedback will bring it back down towards optimum. 
• How does negative feedback work?

  Any change in a system causes an action that reverses the change