Question

Pacinian corpuscles are
A) Glands
B) Pain receptors
C) Naked tactile receptors
D) Encapsulated pressure receptors

Answer 1

Hint: A sheet of connective tissue covers around the entire corpuscle. The capsule comprises 20 - 60 concentric lamellae isolated by gelatinous material, like fibroblasts and fibrous connective tissue, more than 92 percent of that is water.

Complete Answer:
Pacinian corpuscles in glabrous mammalian skin are among the four main forms of mechanoreceptor cells. These are nerve endings present in the skin liable for sensation and pain sensitivity. They only respond to abrupt stimuli and are extremely vulnerable to vibrations.

Now, let us find the solution from the options-
- A gland is a collection of cells in the body of an animal that synthesizes compounds (like hormones) through the bloodstream or into cavities inside the body or its exterior surface (exocrine gland) for release. Thus, option A is not the correct option.
- The sensory nervous system’s mechanism of processing noxious sensations is a pain receptor. A number of physiological and behavioural responses are activated by pain receptors and typically result in a subjective awareness, or perception, of discomfort in human beings. Thus option B is not the correct option.
- The sensory receptors that react to touch are tactile receptors. There are four types of receptors in the glabrous skin of the arm, which are Ruffini, Pacinian, Meissner and Merkel. Just below the skin are the former two, while the latter two are found lower. Thus, the option C is not the correct option.
- Pacinian corpuscle is often microscopic, its body looks like an onion made up of connective tissue layers, wrapping over a nerve ending, situated in the deep skin layers, tendons, etc., and acting as a pressure and sensation sensory receptor.

Thus, the correct answer is option (D) Encapsulated pressure receptors.

Note: Pacinian corpuscles are receptors that respond quickly to sense gross pressure changes and skin vibrations. By opening pressure-sensitive sodium ion channels present in the axon membrane, any dislocation in the corpuscle allows action possibilities to be produced. This enables the influx of sodium ions, forming a possible receptor.