QS Study

Complete pathway for reflex action to called a reflex arc. It is the basic unity of integrated neural activity. It can be considered a ‘shortcut’ in the nervous system. It bypasses the brain for a quick response. It is a part of the circumference of a circle or a regularly curved line. It is a neural pathway that involves both the peripheral and central nervous systems.

Parts – Reflex arc consist of following parts:

Afferent limb: Consist of –

  • Receptor – it is a sensory structure which receives the stimuli. and
  • Afferent nerve – it passes into the spinal cord by way of a dorsal root of the spinal cord.

Center – Spinal cord is the center. Here sensory impulse is converted into motor impulse.

Efferent limb: Consist of –

  • Efferent nerve – it is also known as efferent neuron a is situated in the ventral root of the spinal cord.
  • Effector organ – it may be a muscle or gland which response to impulse received.

Afferent neuron (receptor) and efferent neuron are the two neurons that dominate the pathway. The events that take place during this-

  • The signal is sent to relay neuron by sensory neuron.
  • The motor neuron receives the signal from the relay neuron.
  • Motor neuron further sends the signal to the effector.
  • There is an instantaneous response produced by the effector.