Human Anatomy - Kotsan I. Ya. 2009

Skin
Skin Receptors

The Skin serves as a large receptor field that perceives Temperature, tactile, and pain stimuli. Skin receptors vary in Structure. Some of them appear as treelike branchings of the finest nerve fibers located in the stratum germinativum of the epidermis. Each fiber terminates in Various Forms of thickenings or glomeruli. Other receptors are located in the dermis and feature a diverse, complex structure.

Temperature receptors (thermoreceptors) are divided into two groups:

1) cold receptors;

2) warmth receptors.

Cold-perceiving receptors are called Krause end bulbs. There are about 250,000 of them in the skin. They are located in the dermis, closer to the epidermis.

Warmth receptors are known as Ruffini corpuscles. They are significantly fewer than cold receptors—numbering around 30,000. Thermal receptors are located in the lower part of the dermis.

Tactile receptors (mechanoreceptors) are divided into:

1) Touch receptors;

2) pressure receptors.

Touch receptors include Meissner's corpuscles and Merkel discs. Meissner's corpuscles are located in the papillary layer of the dermis, while Merkel discs reside in the stratum germinativum of the epidermis. Merkel discs are most abundant on the fingertips and Lips.

Receptors that perceive pressure are called Pacinian corpuscles. They are located in the subcutaneous adipose tissue.

Pain receptors (nociceptors) are still insufficiently studied to date. Some authors believe that there are no specialized receptors for pain perception, as excessive stimulation of any receptor can elicit the sensation of pain; others argue that specialized pain receptors exist with their own dedicated nerve pathways. Pain receptors alert the body to danger and trigger protective Reflexes aimed at eliminating the stimulus causing the pain.