Reflex Arc

• Reflex Arc


  • Receptors - detects stimulus and converts it into a nerve impulse
  • Sensory neuron - conducts nerve impulses from receptors to spinal chord.
  • Interneuron - serves as a reflex centre and conducts the impulse to the motor neuron.
  • Motor neuron - conducts impulses from spinal cord to effector.
  • Effector - responds to the stimulus.
• Function of Reflex Arc

  • Heat detected by the skin(receptor) is converted to an impulse.
  • Impulse is conducted along a sensory neuron to the spinal cord.
  • Impulse is conducted to the interneuron.
  • Impulse is then conducted to the motor neuron.
  • Impulse is conducted to the effector organ.
  • The bicep contracts quickly, pulling the arm away.
  • Nerves are separately conducted to the Cerebrum, where the pain is interpreted.
• Alzheimer’s Disease

  • Irreversible brain disease resulting in memory loss and lower IQ.
  • Symptoms appear after 60.
  • Cause is unknown.
  • Develops slowly as plaque forms between neurons and a shortage of neurotransmitters occurs.
  • Neurons decay and the affected part of the brain shrinks.

  Symptoms

  • Unreliable memory
  • Initial symptoms are dismissed as normal aging.

  No available treatment