Wednesday, 5 August 2015

REFLEX ACTION

Spontaneous , involuntary and automatic response without the will of the organism.
The word reflex comes from refluxus which means reflected or directed back, which means that the reflex is reflected back from  the spinal cord.
Examples: coughing, sneezing, blinking of eye, salivation when food is eaten, sweating during exercise.
Reflex arc: The pathway taken by a stimulus to travel from receptor organ  to an effector organ.

Reflex arcs have evolved in higher animals for quick action in emergency situation when immediate action is needed for survival.
Reflexes can be put into two categories:

  1. Unconditioned or simple or natural reflexes:These are inborn and inherited. Eg: blinking of eye, swallowing.
  2. Conditioned or acquired reflexes.: one learns by experienceand gradually responds to it unconsciously.Eg. playing a musical instrument, working on keyboard of a computer,
Watering of mouth at the sight of food or closing of eyes when bright light id focussed on them is a cerebral reflex.
Importance:It checks overloading of the brain, provides immediate response to harmful stimuli and gives the organism a survival value.

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