Coordination and response

• What happens if you don't drink enough water?

  You become dehydrated and your cells shrink.
• What are the consequences of dehydration?

  You may have a headache and can't respond to temperature changes.
• What are stimuli in the context of the nervous system?

  Stimuli are changes in the environment.
• What is the purpose of investigating sensitivity in different areas of the body?

  To understand how different body parts respond to stimuli.
• Which part of the body is very sensitive?

  The fingertips are very sensitive.
• What is the role of the nervous system?

  It allows you to react to your surroundings and change your behavior.
• What is the central nervous system (CNS)?

  The CNS consists of the brain and spinal cord in vertebrates.
• What connects the CNS to the body?

  Sensory and motor neurones connect the CNS to the body.
• What is a reflex?

  A reflex is an automatic, unconscious response to a stimulus.
• What is reaction time?

  Reaction time is how fast you react to a stimulus.
• What is the method to investigate reaction time using a ruler drop test?

  1. Sit with arm resting on a table.
  2. Hold a ruler vertically between thumb and forefinger.
  3. Let go of the ruler without warning.
  4. Catch the ruler as quickly as possible.
  5. Measure the distance caught to determine reaction time.
• What are control variables in an experiment?

  Control variables are factors kept constant to ensure a fair test.
• What is the difference between voluntary and involuntary actions?

  Voluntary actions are chosen responses, while involuntary actions are automatic.
• What happens at a synapse between two neurones?

  An electrical impulse stimulates the release of neurotransmitters across the gap.
• Why is it advantageous to have long neurones instead of short ones?

  Long neurones allow messages to travel faster due to shorter diffusion times for neurotransmitters.
• What are the components of a reflex arc?

  1. Receptor
  2. Sensory neurone
  3. Interneurone
  4. Motor neurone
  5. Effector (muscle or gland)
• How do nerve impulses travel between two neurones?

  They travel across a synapse using neurotransmitters.
• Do reflex arcs travel through conscious parts of the brain?

  No, reflex arcs do not involve conscious parts of the brain.
• What is the effector in a reflex arc if it is a muscle?

  The muscle contracts as a response.
• What is the pathway taken by a reflex arc?

  Stimulus → Receptor → Sensory neurone → CNS → Motor neurone → Effector.
• What are the five sense organs and what are they sensitive to?

  1. Eyes - sensitive to light
  2. Ears - sensitive to sound
  3. Skin - sensitive to touch
  4. Nose - sensitive to smell
  5. Tongue - sensitive to taste
• What is the role of reflex actions?

  Reflex actions protect the body from harm.
• What is the difference between a voluntary and involuntary response?

  A voluntary response is conscious, while an involuntary response is automatic.
• What is the structure of a reflex action?

  • CNS/Spinal Cord
  • Receptor
  • Sensory neurone
  • Inter neurone
  • Effector muscle
• What is the function of the central nervous system (CNS)?

  The CNS coordinates reflexes and actions.
• What is the role of neurotransmitters at a synapse?

  Neurotransmitters diffuse across the synapse to trigger a new electrical signal.
• How does the structure of a synapse facilitate communication between neurones?

  The synapse allows neurotransmitters to diffuse and trigger signals in adjacent neurones.