hormones and ns part 1

• what is a message in the nervous system?

  a nerve output (electrical)
• what is a message in the hormone system?

  a hormone chemical substance eg- insulin
• how does a message travel in the ns?

  along nerves
• how does a message travel in the hormone system?

  in the bloodstream
• where are messages carried to in the ns?

  specific effectors eg-muscles
• where are messages carried to in the hormone system?

  target organs eg-liver
• what are the responses in the ns like?

  localised eg- contraction of individual muscle
• what are the responses in the hormone system like?

  wide spread eg- effects produced by adrenaline
• how quick are the responses in the ns?

  rapid and short-lived eg- movement of the arm
• how quick are the responses in the hormone system?

  slow and long lasting eg- growth and puberty eg- oestrogen and testosterone
• what is a stimulus?

  a change to the surrounding environment
• what does a stimulus produce?

  repsonse
• what is the stimulus recognised by?

  receptor in the body
• if a receptor is stimulated what does it do to the effector (muscle or hormone-producing gland)

  causes it to produce a response
• what is the coordinator?

  brain or spinal chord
• what makes up the CNS- central nervous system?

  brain and spinal cord- coordinators
• what are the 2 main nerve pathways?

  voluntary actions and reflex actions?
• what actions use the brain?

  voluntary actions
• what are voluntary actions?

  involve the brain making a decision about how to respond to a particular stimulus- requires thought and conscious control
• what actions use the spinal cord?

  reflex actions
• what are reflex actions?

  dont involve the brain making decisions, automic responses to stimulus. eg- putting your hand onto hot object, you will move it.
• which actions are faster, reflex or voluntary?

  reflex
• what are reflex actions used for?


  to help humans get out of danger
• why are reflex actions faster?

  nerve impulses dont have to travel to brain for decision to be made- fewer neurons/ synapses involved
• reflex actions are what to a stimulus?

  automatic responses
• what are the 3 types of neurons?

  sensory, association, motor
• what are sensory neurons?

  carry messages from sensory receptors or organs to the cns
• what do sensory neurons synapse with?

  association neurons
• what do the association neurons do?

  they relay info within the cns and link sensory and motor neurons together
• which neurons does the association neuron synapse with?

  both sensory and motor
• what is the reflex arc?


  a pathway of neurons with allows a particular reflex action to occur eg- route taken by nerve impulses (SAM)
• whats the pathway a nerve impulse takes in a reflex action?

  receptor cells in organs detect stimulus- nerve impulses travel through sensory neurons to spinal cord- nerve impulses travel through association neuron inside cord , they're linked with synapses- nerve impulses travel through motor neurone to reach an effector eg muscle- effector responds eg muscle contracts and moves hand away from heat