the nervous system

• What is the primary function of the nervous system?

  To react to surroundings and coordinate behavior
• What are the two main components of the nervous system?

  Central nervous system and network of nerves
• What does the central nervous system comprise?

  Brain and spinal cord
• What is a stimulus in the context of the nervous system?

  A change in the environment detected by receptors
• How do receptors function in the nervous system?

  They pass information as electrical impulses to the CNS
• What role does the CNS play in response to stimuli?

  It coordinates the body’s response to the stimulus
• What are effectors in the nervous system?

  They bring about a response, like muscle contraction
• What are some factors that affect reaction time?

  Tiredness, distractions, caffeine, alcohol
• Why are reflex actions important for survival?

  They help prevent damage to the body
• What is the sequence of a reflex arc?

  Stimulus -> sensory receptor -> sensory neurone -> relay neurone -> synapse -> motor neurone -> effector
• What is the function of relay neurones in a reflex arc?

  They connect sensory neurones to motor neurones
• What structures are found in neurones?

  Nucleus, cell body, dendrites, myelin sheath, axon
• What is the role of the myelin sheath in neurones?

  It insulates the axon and increases impulse speed
• What are synapses in the nervous system?

  Gaps between neurones for impulse transmission
• How do impulses cross synapses?

  Chemicals are released into the gap between neurones
• What happens when chemicals attach to the next neurone at a synapse?

  They set up a new electrical impulse
• What is the role of the nucleus in a neurone?

  It contains the genetic material
• What do branched endings (dendrites) do in a neurone?

  They make connections with other neurones or effectors
• What is the function of axon terminals?

  They connect to effectors to transmit impulses