Adaptation refers to the process by which there is noticeable change over time in the body’s response to some constant stimuli. In the process the body receptor cells are stimulated by the presence of stimuli and they send an impulse through neurons to the Central nervous system. The spinal cord sends the message to the brain for interpretation. Anthea, Hopkins, McLaughlin, Johnson, Warner, LaHart & Wright (1993).
In the first experiment, it is vital to indicate that there was sensory adaptation to the coarseness of the sand paper by the fingers. A stimulus in the experiment was the coarse surface that the receptors were exposed to. The coarseness reduced after a number of rubbings and the surface seemed to be smooth because the sensory cells had become adapted to the surface. During the first rubbing the coarseness seemed to be more because the sensory receptors were still transmitting the message but after several rubbings the message was no longer being transmitted hence the adaptation. Krantz (2005).
In the second experiment the water tasted sweet because the receptors in the mouth sensed the sweet taste and transmitted the message to the brain via the spinal cord. Chemo receptors in the mouth are responsible detecting various chemicals including the sweetness of sugar. However with the plain water in the mouth, the receptors sensed a lack of sugar in the water and hence the transmitted the message to the brain indicating the dullness in the water. The sense cells in the mouth had become adapted to the sweet taste brought about by the water with sugar. With the introduction of the plain water they sensed a dull environment since the sweetness had disappeared simply because a message had been transmitted to the brain via neurons through the central nervous system. Krantz (2005)
In the third experiment in which water in containers with different temperatures, the hands felt the temperatures because of the perception that was facilitated by thermo receptor cells in the hands. In the first container, the thermo receptors were stimulated and hence they sensed a high temperature hence registering with the brain that the water was hot. When the hand is placed in hot water the receptors in the hand are stimulated and they send a signal to the spinal cord which encodes the message. The message is then transmitted to the brain for interpretation indicating that the hand is in a hot environment. (Kolb & Wishaw, 1996)
With the hand in the cold water the thermo receptor cells were stimulated and send an impulse to the spinal cord which in turn sends the message to the brain interpreting the impulse as a lower temperature hence the coldness in the water. When the hands were both transferred into the lukewarm water there was an opposite feeling of the water because of the adaptation process. The right had had became used to the cold temperature such that when it was transferred to the lukewarm water the thermo –receptors were stimulated and delivered a message to the brain informing it of the increased temperature. On the other hand with the left hand that had been put in hot water initially, the thermo-receptors were stimulated and delivered a signal spinal cord then to the brain registering a decreasing temperature. In both cases the sensory system was directed to the new stimulus which was the lukewarm water. The thermo-receptors were stimulated in both hands and hence they immediately send a signal to the brain through the spinal cord informing it of the changed stimuli by the changed temperature of the water. Krantz (2005)
Essentially in all the three experiments there was nervous transmission in which the receptors were stimulated and the central nervous system was involved in the interpretation of the information.