Question

Differentiate between the following pair of terms: stimulus and response impulse.

Answer 1

Hint: The stimulus and response system in the body helps to react accordingly to different situations. It acts majorly in the functioning of the body’s fight or flight, or freeze situations. The response always occurs after the interaction with a stimulus. Furthermore, a response is always specific to a stimulus.

Complete answer: To help the body in maintaining the condition of homeostasis, the nervous system coordinates stimulus and the response mechanism. It is responsible to provide a sense of sensitivity to the body. A stimulus is an external or internal agent that is capable of beginning a response. All living beings are affected by their surroundings and respond to them accordingly. The stimulus should make an evident change in the organism’s internal or external conditions. Different sensory organs are available to different types of organisms to detect a wide range of stimuli to report any change in the environment. A response is a result of the organism’s reaction towards the stimulus. It can be exhibited behaviorally or physically. Every stimulus has its corresponding responses that are generated by the central nervous system. The involuntary responses like an increase in heart rate or breathing are controlled by the spinal cord. But the voluntary response movements like hand or arm movements are a result of the brain’s coordination. The differences between a stimulus and a response are listed below:
a) The major difference is that a response is generated after a stimulus interacts internally or externally to the senses of the body. Hence, the main difference is that stimulus creates a condition or event that initiates a reaction that is a response of an organism towards a particular event.
b) The stimulus can be of various types, intensity, location, and duration. But a response can be physical, behavioural, or cellular-based on the type of stimulus encountered by the sense organs.
c) Signals from the stimulus are detected by sensory nerves and then transferred to the brain or the spinal cord by afferent nerves. The signal from the brain or spinal cord after processing of the stimulus is carried by efferent nerve fibres towards the action or response sites. Thus, the signal from the stimulus is carried in the direction of the central nervous system whereas the signal for response is carried away from the central nervous system.
d) The types of organs involved in the detection of stimulus are eyes, nose, ears, tongue, and skin. But the organs involved in the effector or response system are muscles of the hands, neck, legs, etc. Imagine that you accidentally happen to touch a hot pan, you immediately pull your hand away. The hot pan is the stimulus here and the pulling away of the hand is the response.

Note: The human body encounters hundreds of stimuli in daily life. Some of the stimuli are painful as they cross the threshold limit of sensitivity of sensory nerve fibres. Sometimes, the receptors fail to sense any stimulus. Such conditions are characteristics of coordination failure of the central nervous system.