Suggest six reflex actions of the body. Explain how reflex arcs are the same in all of them.
Answers
Following are the reflex action of the body :- 1) Dilation of pupils in dim light. 2) Patellar reflex 3) Sweating 4) Salivation 5) Shivering. The reflex actions, however, show sudden responses and do not involve any thinking. When we accidentally touch a hot object, we withdraw our hands immediately without thinking. If we do not do this, our hands will burn. The sensory nerves detect the heat. They are connected to the nerves, which move the muscles of the hand. Such a connection of detecting the signal from the nerves (input), and responding to it immediately (output) is called a reflex arc. A reflex arc makes instant and automatic responses possible. It connects the input nerve and output nerve, and meets in a bundle in the spinal chord. In fact, nerves from all over the body meet in a bundle in the spinal cord, on their way to the brain. Therefore, the information input reaches the brain.
Reflex action is an involuntary response shown by body in response to any immediate stimuli. It includes our sensory neuron to send message to the brain which sends back message through motor neurons to the stimuli recipient. This path is called reflex arc.
Following are the examples of reflex action with same reflex arc:
- A reflex action shown by a hand in response to a hot stimuli (stove, candle)
- Change in the size of a pupil in response to a light which act as a stimuli
- Withdrawal of a hand or leg when pricked by a pin
- Blinking of an eye if something gets closer
- Sweating of a body in response to high temperature
- Salivation in response to a sight of exotic food