Synapses and Reflexes

• What are synapses and reflexes primarily involved in?

  Quick transmission of information
• How quickly do neurons transmit information to and from the brain?

  Very quickly
• What does your brain quickly decide regarding stimuli?

  How to respond to a stimulus
• What is the term for the connection between two neurons?

  Synapse
• How is the nerve signal transferred across the synapse?

  By chemicals that diffuse across
• What happens to the chemicals after they diffuse across the synapse?

  They set off a new electrical signal
• What are the characteristics of reflexes?

  • Rapid responses
  • Automatic actions
  • Do not involve conscious brain processes
  • Reduce chances of injury
• What do reflexes help prevent?

  Injury
• How do reflexes respond to stimuli?

  Automatically and rapidly
• What happens when a bright light shines in your eyes?

  Pupils get smaller automatically
• What does the body release when shocked?

  Hormones automatically
• What is the passage of information in a reflex called?

  Reflex arc
• What does the reflex arc involve?

  Transmission from receptor to effector
• How do sensory neurons contribute to reflex actions?

  They send impulses to relay neurons
• What triggers the release of chemicals in a reflex arc?

  Impulse reaching the synapse
• What happens when impulses reach a synapse in a reflex arc?

  Chemicals are released to transmit signals
• What is the role of relay neurons in reflex arcs?

  They connect sensory and motor neurons
• What is the function of motor neurons in reflex actions?

  To carry signals to muscles
• What is the overall purpose of reflex arcs?

  To enable quick responses to stimuli
• What are the steps involved in a reflex arc?

  1. Stimulus detected by sensory receptors
  2. Sensory neurons send impulses to relay neurons
  3. Relay neurons transmit impulses to motor neurons
  4. Motor neurons carry impulses to effectors (muscles)
  5. Effectors respond to the stimulus
• What type of neuron is a sensory neuron connected to?

  Relay neuron
• What happens when impulses reach a synapse between sensory and relay neurons?

  They trigger chemicals to be released
• What do the released chemicals cause in the relay neuron?

  Impulses to be sent along the relay neuron
• What occurs when impulses reach a synapse between relay and motor neurons?

  The same chemical release process happens
• What do the impulses traveling along the motor neuron lead to?

  Movement of a muscle
• What does the muscle do when it contracts?

  It moves your hand away from the bee
• Why is the response to a stimulus quicker than normal responses?

  Because it doesn't require conscious thought
• What is a reflex action?

  • An automatic response to a stimulus
  • Involves sensory, relay, and motor neurons
  • Bypasses conscious thought for speed
• What is the effect of a reflex action on the body?

  It protects the body from harm
• How does a reflex arc function in response to a stimulus?

  Stimulus activates sensory neuron, triggering reflex
• What is the pathway of a reflex action from stimulus to response?

  1. Stimulus detected by sensory neuron
  2. Impulse travels to relay neuron
  3. Chemicals released at synapse
  4. Impulse sent along motor neuron
  5. Muscle contracts in response
• What is the role of the effectors in a reflex action?

  To carry out the response
• Why is it important for reflex actions to be quick?

  To minimize potential harm to the body
• What happens if a reflex action is delayed?

  Increased risk of injury or harm