The difference between a Merkel cell and a Merkel disk is that a Merkel disk is comprised of a single Merkel cell that is coupled with nerve fiber and creates the tactile sensing structure.
And a Merkel cell is a specialized type of cell that is found in the skin's epidermis and the Merkel disk is also a larger structure that is formed by a Merkel cell that connects with a nerve ending and it essentially acts as a sensory unit that is responsible for detecting light touch sensations.
Also structurally a Merkel disc is composed of Merkel cells and their associated Aβ-afferent nerve endings to form a structure of disc-shaped expansion.
Merkel discs also have high tactile acuity and are very sensitive to skin indentation, pressure, hair movement, and other tactile stimuli.
Selective stimulation of the receptors in humans produces a sensation of light pressure.
These several properties have also led to the supposition that Merkel's disks play a major role in the static discrimination of shapes, edges, and rough textures.
Merkel cells, also known as Merkel–Ranvier cells or tactile epithelial cells, are oval-shaped mechanoreceptors essential for light touch sensation and found in the skin of vertebrates.
The Merkel disc, also known as Merkel cell-neurite complex, is a main type of tactile end organ highly abundant in human fingertips, whisker hair follicles, touch domes, and other tactile-sensitive spots throughout mammalian bodies.
The ares of the body that are expected to contain the most merkel discs and tactile corpuscles are areas on the skin.
The areas of skin that are the most sensitive to touch include the hands, fingertips, face, and feet.