Question

An example of stimulus is
A. Hunger
B. Sadness
C. Ache
D. All of the above

Answer 1

Hint: Receptors present in our body can respond to various stimuli that create an impulse. Stimuli are of two types. They are internal stimuli and external stimuli. Internal stimuli are those stimuli that are produced within the body. External stimuli comprise stimuli from the external environment.

Complete answer: Receptors along with the surrounding non-neural cells are called sense organs. Stimuli are of several types. Mechanical stimuli are the stimuli that are mechanical in nature. They create pressure changes and are detected by mechanoreceptors present in our body. Touch stimulus is an example of a mechanical stimulus. It is detected by tactile receptors. Stimuli that are produced by temperature changes are called thermal stimuli. Changes in warm and cold temperatures are detected by thermoreceptors. Noxious stimuli are the stimuli that create tissue damage and cause pain. They are detected by nociceptors. Light stimuli are detected by electromagnetic receptors like rods and cones in the eye. Chemical stimuli are created by chemical changes. Taste and smell is caused by chemical stimuli.
-Hunger is an example of a stimulus that stimulates several receptors. The discomfort produced by hunger is due to secretions present in our gut. Hunger is controlled by the hunger centres present in the hypothalamus. Ventromedial nuclei present in the hypothalamus act as satiety centres and Lateral nuclei act as a feeding centre.
-Sadness is an example of an emotional stimulus. Emotions can also stimulate various receptors impulses are generated. It is processed by the central nervous system and we feel certain emotions by this.
-Ache or pain is an example of noxious stimuli and is detected by nociceptors. For example, when our finger is cut by a knife, impulses are generated. They are processed by CNS and we feel pain.
Hence, the correct answer is Option D.

Note: Receptors that are present in the sense organs can detect a particular stimulus in a lower threshold than the other receptors. For example, the threshold of stimulus for touch stimulus will be lowest in touch receptors. It will be higher in other receptors like chemoreceptors. The threshold energy of a stimulus is the minimum energy needed by a stimulus to stimulate a receptor.