How is the reflex action occur in the human body ?
The reflex action
Your body makes an involuntary response by the nervous system and this happens when your body is subjected to the external stimuli such as the strong light , the heat or smell ……..etc .
This involuntary response is called the reflex action , The reflex action is the automatic (spontaneous ) response of the body to the different stimuli and the responsible organ for the reflexes is the spinal cord .
Examples of the reflex action
Your body makes the reflex action when you touch a plant with sharp thorns , you move your hand away quickly , The body withdraws the hand quickly on touching a hot surface , and it sweats in the hot days .
Constriction of the eye pupil occurs on the intense light and its widening occurs on the dim light , You blink when something gets close to the eye , and your body is trying balance during sliding down due to the reflex action .
We run quickly when we see a fast moving car coming towards us or when we hear a near explosion due to the reflex action and we secrete the saliva on seeing or smelling the good food .
How is the reflex action occur when you touch a plant with sharp thorns ?
The severity of the thorns affects the nerve endings in the fingers producing the nerve impulses , The nerve impulses are transmitted to the spinal cord through a sensory nerve fiber .
There are some nerve impulses produced by the spinal cord which transmitted through a motor nerve fiber to the arm muscles ( without the brain’s intervention ) , So , the muscles contract and the arm is withdrew away from the thorns .
The other nerve impulses produced by the spinal cord are transmitted to the sensory centers in the brain which lead to the true sense of pain .
The reflex action when you touch hot surface
The sensory neuron carries the information in the form of a nerve impulse to the spinal cord , The sensory receptor in the hand detects the hot object , An interneuron in the spinal cord passes the impulse to a motor neuron .
The motor neuron carries the nerve impulse to the muscle , So , the muscle contracts and the hand pulls away from the hot object .