Nervous system

• What is the nervous system made up of?

  Neurons
• What are sensory receptors responsible for?

  They detect changes in the environment.
• What do receptors in the skin detect?

  Pressure
• What do receptors in the nose detect?

  Chemicals
• What are the different types of stimuli detected by receptors?

  • Light
  • Chemical
  • Pressure
  • Vibrations
• What happens when a receptor detects a stimulus?

  It sends out an electrical impulse.
• What is the term for the electrical signal sent by a receptor?

  Electrical impulse
• What is the role of dendrites in a neuron?

  Dendrites carry electrical impulses towards the cell body.
• What is the function of the axon in a neuron?

  The axon carries electrical impulses away from the cell body.
• What is the myelin sheath and its function?

  The myelin sheath acts as an electrical insulator, speeding up impulses.
• What type of neuron carries impulses from receptors to the cell body?

  Sensory neuron
• What is the role of the motor neuron?

  The motor neuron carries impulses from the cell body to effector cells.
• What are synapses?

  Synapses are the gaps between neurons.
• How is a nerve signal transferred across a synapse?

  By neurotransmitters that diffuse across the gap.
• What happens to the nerve signal at a synapse?

  The signal is slowed down due to the time taken for neurotransmitter diffusion.
• What are reflexes?

  Reflexes are automatic, rapid responses to stimuli.
• What is the pathway of a reflex action?

  It goes from a receptor to a sensory neuron, then to a relay neuron, and finally to a motor neuron.
• What happens when a stimulus is detected by receptors?

  Impulses are sent along a sensory neuron to a relay neuron.
• What occurs at the synapse between a sensory neuron and a relay neuron?

  A neurotransmitter is released, sending impulses along the relay neuron.
• What happens when the impulse reaches the motor neuron?

  The impulse travels along the motor neuron to the effector.
• What is the effect of a reflex action, such as in response to a bee sting?

  The muscle contracts and moves the hand away.
• Why are reflexes quicker than normal responses?

  Because they do not require conscious thought.