Question

What are reflex actions? Give two examples. Explain a reflex arc. ​

Answer 1

Answer:

(i) If we unknowingly touch a hot plate, we immediately move our hand away from it.

(ii) Moving our foot away on stepping something sharp.

Reflex arcs have evolved in animals because the thinking process of brain is not fast enough.

Answer 2

$\sf{\purple{Reflex\:Action:}}$The sudden involuntary movement in a voluntary organ; in response to a stimulus; is called reflex action.

${\red{\sf{Examples\:of\:reflex\:action:}}}$

(a) Moving your hand away from a hot iron plate

(b) Blinking of eyes

$\sf{\green{Reflex\:Arc: }}$The path of electrical impulse during a reflex action is called reflex arc. A reflex arc is composed of a sensory neuron, spinal cord, motor neuron and muscle. It involves following steps:

The sensory neuron picks signals from the stimulus and carries the signals to the spinal cord.

Spinal cord process the signals and sends message through the motor neuron.

Motor neuron transmits the signals to the effector muscle so that the muscle can take immediate action.