Human Nervous System

• What is the function of the nervous system?

  React to the surroundings and co-ordinate an effective response.
• How does stimulus lead to a response being carried out by the body.

  -stimulus is converted into an electrical impulse by the receptors.

  -the electrical impulse passes along the sensory neurones to the central nervous system (CNS).

  -the CNS coordinates an appropriate response and an electrical impulse is sent along motor neurones to the effector, which carries out the response.
• What sequence of events describes how the nervous system works.

  Stimulus → Receptor → Coordination → Effector → Response
• What is a reflex action?

  An involuntary and automatic response which does not involve any concious input from the brain
• Why are reflexs actions important?

  Reflex actions aid survival by preventing harm to the body
• Describe how a reflex action occurs via reflex arc.

  -The stimulus is detected by a receptor

  -An electrical impluse is carried along a sensory neurone to the spinal cord (part of the CNS)

  -At a synapse between a sensory and a relay neurone, a chemical diffuses across the gap and stimulates a new impluse which passes along the relay neurone

  -the same process occurs at a synapse between a relay neurone and a motor neurone. At the effector, a response is carried out
• What is the difference between a reflex and concious pathway?

  Within a reflex pathway, the coordination centre is a relay neurone which is found in the spinal cord and unconcious part of the brain. In a concious pathway, the co-ordination centre is found within the concious part of the brain.