2.2 Control and Communication

• What does CNS stand for ?

  Central Nervous System
• What makes up the CNS?

  • Brain
  • Spinal Cord
• Receptors

  Body structures that can detect environmental changes
• Effectors

  Parts of the body that can make responses to environmental changes
• Sections of the brain

  • Cerebrum
  • Medulla
  • Cerebellum
• Cerebrum

  Controls memory, personality and conscious thought
• Medulla


  Controls heart rate and breathing rate
• Cerebellum

  Controls balance and co-ordination
• Neuron types

  • Sensory
  • Inter
  • Motor
• Reflex arc

  A reflex arc is designed to be rapid and protective, that involves an inter neuron in the spinal cord
• Pathway of an impulse during a reflex response

  1. Stimulus

  2. Sensory neuron

  3. Inter neuron

  4. Motor neuron

  5. Response (muscle or gland)
• Synapse

  A gap between two neurons
• How a synapse works

  Chemical transmitter substances released from tiny vacuoles at the end of one neuron diffuse across the synapse to generate an electrical impulse in the next neuron
• Nervous system

  Uses electrical impulses through nerves
• Endocrine system

  Produces hormones that travel through the blood
• How hormones are transported

  Hormones are transported in the blood plasma to target body tissues where they bind to cells to produce a response
• What are Hormones

  Proteins and chemical messengers
• What hormone is produced when Blood glucose level rises

  Insulin is produced
• What hormone is produced when Blood glucose level drops

  Glucagon is produced
• Target cells of insulin and glucagon

  In the liver
• Insulin


  Turns glucose into glycogen
• Blood glucose concentration rises


  After eating
• Blood glucose concentration falls


  If you have not eaten for a long time or after exercise