Question

1. Adaptation of Touch receptors: use a penny, with the examinee’s eyes closed, place it on their forearm, start timing and record when the examinee no longer feels the penny. Add a second penny to another location, repeat the timed test. For the third portion stack the 3 more pennies at the first location, and time the examinee until they no longer feel the pennies.

a. Why is the adaptation of the touch receptors particularly important while we wear clothes? If the answer is not immediately apparent, consider the opposite phenomenon: what would happen, in terms of sensory input, if these receptors did not exhibit adaptation?

b. Are these fast or slow adapting receptors, and identify the receptor?

Answer 1

a)Sensory adaptation refers to a condition in which after constant exposure to particular stimulus leads to reduction in sensitivity to particular stimuls . It is important because we have other sensory organs which are sending informations in brain which are more relevant and it is evolutionary and our brain tries to focus on changes to stimulus as there is no new information in constant sensory stimulus. We are evolved to conserve precious energy used by the brain to process only changes to sensory inputs.

Eg while playing outdoor games it is not important for brain to receive signals about the touch sensation of clothes rather to receive visual inputs and joint position ,propioception through receptors to brain so sensory adaptation occur and other senses will be able to send signals .

If in case adaptation will take time then in such cases stimulus is present but it will gradualoy decreses with time .

B) Fast adapting receptors ( Rapidly acting receptors )
Function - It can detect rate of change of stimulus
Receptor is Pacinian corpuscles
Pacinian corpuscles react only to sudden stimuli or change of stimulus so pressures through clothes which are constantly compressing there shape is not given importance so we dont fell for clothes in long term .
Location - Dermis ,ligaments ,joint capsule,peritoneum and extragenitalia
Sensory modality - Vibration and deep pressure