PAPER 2 BIOLOGY

• What is homeostasis?

  Homeostasis is the body's ability to maintain a stable internal environment despite external changes.
• Why does the body need to maintain optimal conditions?

  For optimal enzyme action and cell function.
• Internal conditions such as..

  Blood glucose concentration

  Blood pH
• External conditions such as..

  Room temperature

  The amount of fluids you drink
• Control system

  receptor -> coordination centre -> effector
• Role of receptor?


  Detects change in the internal or external environment
• Role of coordination centre?


  Interprets changes and organises a response
• Role of effector? 


  Carries out the response
• Where are the coordination centres located in the body?

  Spinal cord

  Brain
• 2 types of effectors and what they do?

  Muscles: Contract to produce movement.

  
  

  Glands: Release hormones.
• Nervous or endocrine system faster?

  Nervous
• Negative feedback 


  whenever the levels get too high / low they are decreased / increased
• If our body temp gets too high , negative feedback will cause our temp to..

  decrease back down.
• How does negative feedback work?

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