The skin, or cutis, is a continuous tissue belonging to the integumentary system. It is composed of three main layers which, from the outside towards the inside, take the name of: epidermis, dermis and hypodermis (or subcutaneous layer).
The skin has two fundamental and extraordinary properties: self-repair (it regenerates following an injury) and extensibility (it adapts perfectly to changes in body size that occur over the course of life).
The skin performs numerous and very important functions:
- protects us from trauma, ultraviolet radiation, microorganisms and chemical agents.
- Prevents the loss of fluids; For example, if a "burn causes the destruction of a tenth of the skin surface, the loss of fluids and electrolytes can lead to fatal consequences.
- It participates in the thermoregulation mechanism, exploiting the intervention of the sweat glands and the ability to regulate blood flow, increasing (vasodilation) or slowing down (vasoconstriction) the dispersion of heat. The hypodermis, the deepest layer of the skin, retains much more heat the greater its lipid thickness; for this reason, overweight people suffer more from the summer heat.
- Coordinates the immune response against tumors and pathogens.
- The skin has metabolic properties, since the synthesis of vitamin D occurs precisely at the skin level. The skin also represents an important lipid reserve.
- The skin also has a very important sensory function: with its most superficial layer it records and transmits pressure (tactile), pain and thermal stimuli, while with the deeper one it also perceives thermal and vibratory signals.
Insights
Histological and functional organization of the five layers that compose it
Cellular renewal of the "epidermis: what" it is, how it happens, what it is influenced by
The skin represents an "effective protective barrier against dehydration, let's see in detail this precious characteristic
Corneocytes
Odland's bodies
natural factor
of hydration
Hydroplipid film and epidermal lipids: how they are produced, what functions they cover and why they are so important for the health of our skin
Skin colour
and melanin
What does skin color depend on? What are the functions of melanin?
What is the meaning of the various light, dark and raised spots on our skin?
It is "the deepest layer of the skin, a connective tissue constituted by a" scaffolding of connective fibers, between the meshes of which lipidic masses are inserted. Interesting study on white and brown adipose tissue
Sweating
Apocrine Giandole
Sebaceous glands
In the skin we find three types of glands: sweat, apocrine and sebaceous. Each of them has a very specific functional meaning, let's see which one (with interesting references to acne and seborrhea)
Hair follicles
Hair and hair
The nails
They are part of the skin appendages and have particular functions that we will examine briefly after having understood their histological characteristics
Skin aging is an inevitable biological phenomenon, understanding its causes can help slow it down
Nickel allergy is the most common cause of allergic contact dermatitis, a disease that produces skin lesions very similar to those of eczema.
The patch test is a test used for diagnostic purposes to identify those substances which, once placed in contact with the skin, cause a local inflammatory reaction.
Goose skin or skin anserine is characterized by the transitory appearance of small skin reliefs close to each other, these tiny hills are formed by the reflex, and therefore involuntary, contraction of the erector muscles of the hair.
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