Pacinin

Pacinin, also known as Pacinian corpuscles, are specialized sensory receptors found in the skin of humans and other mammals. They are among the largest of the mechanoreceptors and are responsible for detecting deep pressure and vibration. Pacinin are located in the dermis and subcutaneous tissue, and are particularly numerous in areas sensitive to touch, such as the fingertips, palms, soles, and genitals.

These receptors are encapsulated nerve endings with a characteristic onion-like structure. Each Pacinin consists of a central nerve fiber surrounded by concentric layers of connective tissue, similar to a series of lamellae. When pressure or vibration is applied to the skin, it deforms the Pacinin, causing the nerve fiber within to generate an electrical signal. This signal is then transmitted along the nerve to the brain, where it is interpreted as touch or vibration.

Pacinin are highly sensitive to rapid changes in pressure and vibration. They adapt quickly to sustained pressure, meaning that they respond most strongly when a stimulus is first applied or removed. This rapid adaptation allows us to perceive changes in our environment and to distinguish between different types of tactile stimuli. The sensitivity of Pacinin to vibration is crucial for tasks such as detecting texture and discerning fine details through touch. Damage to Pacinin can impair the ability to sense pressure and vibration, potentially affecting fine motor skills and the perception of the environment.