biology 🧬

• What does the nervous system enable humans to do?

  React to surroundings and coordinate behavior
• How does information from receptors reach the CNS?

  It passes to the central nervous system
• What are the two main structures of the CNS?

  The brain and spinal cord
• What do effectors do in the nervous system?

  They respond by contracting muscles or secreting hormones
• What are reflex actions designed to do?

  Protect the body through automatic responses
• What is the first step in a reflex action?

  The pain stimulus is detected by receptors
• What type of neurone carries impulses to the CNS?

  A sensory neurone
• What happens after the impulse reaches the CNS?

  It passes through a relay neurone
• What does a motor neurone do?

  It carries an impulse to the effector
• How does the effector respond in a reflex action?

  By rapidly withdrawing a limb from pain
• Are neurones directly connected to each other?

  No, they are not directly connected
• What occurs at a synapse?

  A chemical is released when an impulse reaches it
• What happens to the chemical released at the synapse?

  It diffuses across the gap to the next neurone
• What does the chemical released at the synapse cause?

  An electrical impulse to be generated in the second neurone
• What is the method to investigate human reaction time?

  1. Hold a ruler at the end.
  2. Subject positions fingers on the 50cm line.
  3. Release the ruler; subject catches it.
  4. Measure the distance fallen.
  5. Repeat with subjects who consumed caffeine.
• What is the independent variable in the reaction time experiment?

  Whether the subject has taken caffeine
• What is the dependent variable in the reaction time experiment?

  The distance the ruler travels
• What are the control variables in the reaction time experiment?

  Age, sex, and mass of subjects
• What is a consideration when conducting the reaction time experiment?

  It is difficult to control the variables
• Why is it important to have large numbers of subjects in the experiment?

  To obtain reliable results and averages
• What are the risks associated with the reaction time experiment?

  There are limited risks with this experiment
• What is the gap between two neurones called?

  A synapse
• What type of neurone sends impulses from receptors to the CNS?

  A sensory neurone
• What are the key terms related to the nervous system?

  • Homeostasis
  • Receptor
  • Effector
  • Central nervous system (CNS)
  • Synapse