control & communication

• The CNS (central nervous system) is made up of the brain and spinal cord.
• The nerves are part of the peripheral nervous system and they lead to and from all organs and systems
• The parts of the nervous system:

  A) brain

  B) spinal cord

  C) central nervous system

  D) peripheral nervous system

  
• The medulla controls rate of breathing and heartbeat, and is located in the centre of the brain
• The cerebellum controls balance and muscular coordination, and is located at the back of the brain
• The cerebrum is the largest part of our brain and controls higher order functions such as thought, perception and personality
• reflex arc

  A) receptor

  B) sensory neuron

  C) synapse

  D) inter neuron

  E) motor neuron

  F) effector

  G) spinal cord

  
• receptors detect stimuli and send signals to the CNS via sensory neurons to initiate a response
• • Motor neuron - enable a response to occur at an effector (a muscle or gland)
• When a receptor detects a potentially harmful stimulus the sensory neurone passes this information to an inter neurone in the spinal cord. The relay neurone passes this information onto a motor neurone and this causes a response in an effector (usually a muscle).

   
• electrical impulses carry messages along neurons, when the impulse reaches the end of a neuron it stimulates the release of a chemical, this chemical diffuses along the gap between the 2 neurons, when the chemical reaches the second neuron it stimulates a new electrical impulse, this is called a synapse.
• hormones are chemical messengers which are carried around the body in the bloodstream
• hormones are produced in endocrine glands
• The target tissue contains special receptor proteins that will recognise the hormone. The receptor proteins ensure only the target tissues are affected by the hormone.

  A) receptor

  B) hormone

  C) hormone

  D) receptor

  
• An increase in blood glucose leads to the following action.

  1. The pancreas responds by releasing the hormone insulin.
  2. Receptors in the liver detect the insulin.
  3. In response, the liver starts to convert excess glucose into glycogen.
  4. The blood glucose levels fall.
• Your liver stores approximately 100 grams of glucose in the form of glycogen. Glycogen is made up of chains of glucose and this store can be added to or removed from depending on your body’s needs.
• A decrease in blood glucose leads to the following action.

  • The pancreas responds by releasing the hormone glucagon.
  • Receptors in the liver detect the glucagon.
  • In response the liver starts to convert glycogen back into glucose.
  • The blood glucose levels rise.
• Three Main Parts of the brain:

  A) cerebrum

  B) cerebellum

  C) medulla