The human nervous system

• What is the internal environment of your body?

  the conditions within your body
• What is Homeostasis?


  The ability to maintain a stable internal environment so your body works at is optimum
• To survive your body needs to control:

  • Water levels
  • Temperature
  • Blood glucose levels
  • salt (ion) levels
• How do you increase someone's water level?

  • consuming water in food/drink
• How do you decrease someones water levels?


  • sweat
  • Urinate
• How do you increase someones salt (ion) levels?

  • consuming salt in food/drink
• How do you decrease someones salt levels?


  • Sweat
  • Urinate
• How would you increase someones blood glucose levels?

  • Consuming glucose in food/drink
• How would you decrease someones blood glucose levels?


  • Insulin removes glucose
• How does your body increase its temperature when cold?

  By shivering
• How does your body decrease its temperature?


  • sweating
  • going red
• What is negative feedback?


  the process in which your body regulates your internal environment
• What is the process of negative feedback?

  1. Receptors detect a stimulus
  2. They send a message to the brain
  3. The brain then sends orders for the effectors to regulate the internal environment
• what is a stimulus?


  A change in the internal environment that the receptors have to detect
• What are the receptors?


  Groups of specialised cells that detect the stimuli from the internal or external environmental changes, they can also be part of the chemical or nervous system. They turn the stimuli into electrical impulses.
• What are the effectors?


  Things like the muscles that respond to the message send by the the brain and these have a purpose to actually regulate the change
• What specific conditions do enzymes have to have in order to work well?

  Temperature and pH
• Why does the temperature of the body need to be controlled?

  Enzymes can only work at certain temperatures
• Why do we need to control the water levels of the body?

  it will effect osmosis
• Why is it important to control the glucose levels in your blood?

  High blood glucose can lead to circulatory problems
• What is a co-ordinator?


  A part of the negative feedback where all the information from the receptors in processed and a response is produced.
• What two systems make up the nervous system?

  • Central system
  • Peripheral
• Where are the receptors located?

  In the sensory organs such as the ear or eyes
• What is the CNS?

  Also known as the central nervous system, it controls your body and is made up by the brain and spinal cord
• Neurones are nerve cells that transmit electrical impules through your body.
• The peripherial nervous system is made up of neurones.