The Nervous System

• Why are reflex actions important?

  They help protect us from danger
• What is homeostasis?

  Keeping internal conditions constant
• What are the components of automatic control systems?

  Stimulus, receptor, coordination center, effector, response
• What are the two parts of the nervous system?

  Central nervous system and peripheral nerves
• What does the central nervous system consist of?

  The brain and spinal cord
• What are neurons also known as?

  Nerve cells
• What is the role of effectors in the nervous system?

  To bring about a response
• What are the two types of effectors mentioned?

  Muscles and glands
• How does the nervous system help humans?

  By enabling reactions to surroundings
• What is the reflex arc?

  A pathway for reflex actions
• What happens when you touch a hot object?

  The reflex arc is activated
• What is the stimulus detected when touching a hot object?

  Heat
• What type of neuron carries impulses to the central nervous system?

  Sensory neuron
• What is the junction at the end of a sensory neuron called?

  Synapse
• What happens at the synapse in the central nervous system?

  A chemical is released to trigger an impulse
• What triggers an electrical impulse in a motor neuron?

  A chemical released at the synapse
• What does the electrical impulse in a motor neuron lead to?

  Contraction of a muscle
• What is the response when pulling a hand away from heat?

  Withdrawal of the hand
• How do reflexes differ from other actions in terms of decision-making?

  Reflexes do not involve conscious decision-making
• Why are reflexes considered automatic and rapid?

  They bypass conscious brain processing
• What is the main function of the central nervous system?

  To act as a coordinator
• What are the stages of the reflex arc?

  1. Stimulus detected by receptor
  2. Impulse travels along sensory neuron
  3. Impulse reaches synapse, triggering a chemical release
  4. Chemical triggers impulse in relay neuron
  5. Impulse travels to motor neuron
  6. Motor neuron sends impulse to effector
  7. Effector (muscle) contracts, response occurs