In our body, skin having a total surface area of 1.5 m 2 to 2.5 m 2 is functionally associated with internal organs and reflects their condition both in normal and pathological conditions. Having a complex three-layer structure, it contains nerve endings, the so-called skin receptors, which perceive irritations from the external environment. In this article we will try to answer a few questions. What receptors are located in the skin? What is their structure and function? How is the interaction of the integument of the human body and environmental conditions ensured.
What receptors are located in the skin
The anatomy and physiology of man is studying not only the basic systems of the body, but also what receptors are located in the skin. Biology (Grade 8) explains the morphological and functional features of the tactile sensory system, based on the specific structure and functions of various types of skin receptors that make up it.
There are three types of receptors in the skin: mechanoreceptors, thermoreceptors, and nocireceptors (pain). The latter are located in most cases in the epidermis - the outer layer of the skin, consisting of an epithelium located in several rows. Their upper part is keratinized, desquamated and replaced due to the lower layers. In humans, the epidermis is almost completely updated within a month.
The first two types - mechanoreceptors and thermoreceptors - are mainly found in the dermis or the skin itself, in the layer of connective tissue, in which all its structural elements are located, including blood and lymph vessels, hair bags and glands.
Skin receptor function
Human skin performs several important functions, one of which is receptor. It is explained by the fact that the integument of the body is a receptor field that provides the central nervous system with information both about changes in the skin itself and about the nature of the stimuli. Active points of the skin are associated with certain areas of the brain, and through them with the musculoskeletal system and internal organs.
Skin receptors are nothing but the peripheral section of a musculocutaneous analyzer, which also includes nerves that carry excitation from receptors and sites-centers in the brain located in its stem part. As mentioned earlier, the receptors of the skin analyzer are located in the epidermis and the skin itself. Their structure and functions are not the same.
For example, tactile receptors - Meissner bodies, are markers that determine the speed of touch and are located in the epidermis, and Paccini bodies, which are located deep in the dermis, are responsible for changing the acceleration of tactile stimuli. The nature of the sensations depends not only on which receptors in the skin perceive the action of the external environment, but also on the frequency of the stimulus. If it is unchanged for a long time, a sensation of pressure arises, with a short-term action - touch, and at a high rate of change in the strength of the stimulus - a sensation of vibration.
The smallest threshold of sensitivity is characteristic of skin receptors located on the tip of the tongue and lips, the higher is on the fingertips, palms, inner bends of the elbows, and the skin of the abdomen, feet and back has the highest threshold of sensitivity.
Features of temperature receptors
Temperature receptors control the normal level of metabolic reactions of homeostasis. They are located in the walls of the arteries and provide thermoregulation - balancing the heat transfer processes of homeothermic organisms with a constant body temperature. Thus, the adaptive level of a living organism depends on which receptors are located in the skin and how quickly they signal changes in the environment.
Specificity of nocireceptors
Studying the question of which receptors are located in the skin will be incomplete if we do not consider the structural features of pain receptors. Contrary to pharmaceutical advertising, which helpfully offers to get rid of pain once and for all, we note that it is painful sensations that are a protective reaction of the body that signals it with a potential danger. Nocireceptors have the form of single branched nerve endings, perceiving a variety of excessively strong irritants of heat, pressure, cold. The greatest number of them is located on the fingertips, in the periosteum, in the walls of blood vessels, in the arachnoid membrane of the brain.
Pain can be considered as a form of tactile perception, so it is important not only what receptors are located in the skin, but also how clearly they respond to strong irritants. The very sensation of pain is considered as a subjective feeling, which we express while in a special negative psycho-emotional state. It is provoked by the influence of stimuli of a specific sensory modality.
This article examined the features of the structure and functions of skin receptors .