Reflex action, Biology

REFLEX ACTION -

  • Marshel Hall discovered reflex action. Best & Taylor defined it. Reflex action is functional unit of CNS.
  • It is sudden, immediate involuntary action against external stimuli. In man it is poly-synaptic.
  • If we prick needle on skin, somatic sensory nerves bring impulses to grey matter. Here these are analysed & order is given to muscle by motor nerve.
  • The path from which impulse is passed is reflex arch.
  • Minimum time is consumed in it. It is not under control of brain.

Some common reflex actions are -

1. Coughing

2. Yawning

3. Sneezing

4. Knee-jerk reflex

5. Bleenking of eyes

6. Scratch reflex

EXAMPLE -

1.       Cycling.

2.       Watering of mouth.

3.       Blinking of eyes in sharp light.

4.       Withdrawal of leg in pithed frog.

5.       Flow of bile from gall bladder.

6.       Peristalasis.

7.       Heart beat.

2243_reflex action.png

SIGNIFICANCE -

1. It enables animal to respond immediately to the harmful stimuli so that no harm is caused to it.

2. It gives more time to brain to work.

Posted Date: 10/3/2012 2:16:32 AM | Location : United States







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