The nervous system

• What does the human nervous system consist of?

  The brain, spinal cord and nerve cells
• What is the CNS?

  Central Nervous System- Brain and Spinal Cord
• What is the peripheral nervous system?

  nerve cells that carry information to or from the CNS
• How is information transported?

  Through nerves
• What are neurones?

  Long cells which carry electrical impulses
• What is there when two neurones meet?

  Synapse
• How do signals pass along synapses?

  Chemically
• What are sense organs?

  Organs that detect stimuli
• What is stimuli?

  Something that sets of a reaction in the nervous system
• What is an example of a sense organ?

  Eyes
• What do sense organs contain?

  Receptor cells
• What are receptor cells?

  A cell that can detect stimuli inside or outside the body
• What do receptor cells produce?

  Electrical impulses
• What is the stimulus for touch?

  Temperature, pressure and pain
• What is the stimulus for taste?

  Chemical tastes (in food and drink)
• What is the stimulus for smell?

  Chemical smells (in the air)
• What is the stimulus for sight?

  Light
• What is the stimulus for hearing?

  Sound
• What are effector muscles?

  Parts of the body that produce a response to a detected stimulus
• What is an example of what an effector muscle does?

  A muscle contracting to move an arm
• What is an example of a reflex response?

  The pupil getting smaller when light is bright
• How does a reflex response happen?

  1. Stimulus
  2. Receptor cells
  3. Sensory neurone
  4. Synapse
  5. Relay neurone
  6. Synapse
  7. Effector muscle
  8. Response
• What is the coordinator?

  The brain or spinal cord
• What’s the nature of a reflex action?

  Automatic, fast and usually protective
• What’s the difference between a normal action and a reflex action?

  The brain doesn’t control a reflex action, the spinal cord does
• What is the nerve pathway in a reflex action called?

  A reflex arc
• How is the amount of light entering the eye controlled?

  A reflex action
• What happens as a response to bright or dim light in the eye?

  The size of the pupil changes
• How is pupil size controlled?

  By the muscles of the iris
• What is the eye?

  A sense organ that responds to light
• What is a reflex response?

  Involuntary
• What is the cornea?

  Transparent outer layer of the eye.
• What is the pupil?

  A hole in the iris
• What is the iris?

  The colored part of the eye.
• What is the lens?

  A flexible transparent structure
• What is the sclera?

  The opaque white protective layer
• What is the blind spot?

  Where the optic nerve leaves the eye
• What is the optic nerve?

  The nerve located at the back of the eye
• What is the retina?

  The light-sensitive area that contains photoreceptors
• What is the choroid?

  A black pigmented layer of the eye