Club X Acne

The Skin

Skin is the largest organ of the integumentary system made up of multiple layers of epithelial tissues that guard underlying muscles and organs. Skin pigmentation  varies among populations, and skin type can range from dry skin to oily skin.

Skin layers

Skin is composed of three primary layers: the epidermis, which provides waterproofing and serves as a barrier to infection; the dermis, which serves as a location for the appendages of skin; and the hypodermis (subcutaneous adipose layer).

Epidermis

Epidermis, “epi” coming from the Greek meaning “over” or “upon”, is the outermost layer of the skin. It forms the waterproof, protective wrap over the body’s surface and is made up of stratified squamous epithelium with an underlying basal lamina.

The outermost epidermis consists of keratinised cells. The underlying connective tissue section, or dermis, and a hypodermis, or basement membrane. The epidermis contains no blood vessels, and cells in the deepest layers are nourished by diffusion from blood capillaries extending to the upper layers of the dermis. The main type of cells which make up the epidermis are keratinocytes, with melanocytes and Langerhans cells also present. The epidermis can be further subdivided into the following strata (beginning with the outermost layer): corneum, lucidum (only in palms of hands and bottoms of feet), granulosum, spinosum, basale. Cells are formed through mitosis at the basale layer. The cells, move up the strata changing shape and composition as they die due to isolation from their blood source. The cytoplasm is released and the protein keratin is inserted. They eventually reach the corneum and slough off (desquamation). This process is called keratinization and takes place within about 30 days. This keratinized layer of skin is responsible for keeping water in the body and keeping other harmful chemicals and pathogens out, making skin a natural barrier to infection

 

Sublayers

Epidermis is divided into the following 5 sublayers or strata:

• Stratum corneum
• Stratum lucidum
• Stratum granulosum
• Stratum spinosum

Blood capillaries are found beneath the epidermis, and are linked to an arteriole and a venule. Arterial shunt vessels may bypass the network in ears, the nose and fingertips.

Dermis

Dermis

The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many nerve endings that provide the sense of touch and heat. It contains the hair follicles, sweat glands, sebaceous glands, apocrine glands, lymphatic vessels and blood vessels. The blood vessels in the dermis provide nourishment and waste removal to its own cells as well as the Stratum basale of the epidermis.

Structure

The dermis is structurally divided into two areas: a superficial area adjacent to the epidermis, called the papillary region, and a deep thicker area known as the reticular region.

Papillary region

The papillary region is composed of loose areolar connective tissue. It is named for its fingerlike projections called papillae, that extend toward the epidermis. The papillae provide the dermis with a “bumpy” surface that interdigitates with the epidermis, strengthening the connection between the two layers of skin.

In the palms, fingers, soles, and toes, the influence of the papillae projecting into the epidermis forms contours in the skin’s surface. These are called friction ridges, because they help the hand or foot to grasp by increasing friction. Friction ridges occur in patterns that are genetically and epigenetically determined and are therefore unique to the individual, making it possible to use fingerprints or footprints as a means of identification.

Reticular region

The reticular region lies deep in the papillary region and is usually much thicker. It is composed of dense irregular connective tissue, and receives its name from the dense concentration of collagenous, elastic, and reticular fibers that weave throughout it. These protein fibers give the dermis its properties of strength, extensibility, and elasticity.

Also located within the reticular region are the roots of the hair, sebaceous glands, sweat glands, receptors, nails, and blood vessels.

Tattoo ink is held in the dermis. Stretch marks from pregnancy are also located in the dermis.

The hypodermis is not part of the skin, and lies below the dermis. Its purpose is to attach the skin to underlying bone and muscle as well as supplying it with blood vessels and nerves. It consists of loose connective tissue and elastin. The main cell types are fibroblasts, macrophages and adipocytes (the hypodermis contains 50% of body fat). Fat serves as padding and insulation for the body.

Microorganisms like Staphylococcus epidermidis colonize the skin surface. The density of skin flora depends on region of the skin. The disinfected skin surface gets recolonized from bacteria residing in the deeper areas of the hair follicle, gut and urogenital openings.

As the interface with the surroundings, skin plays the most important role in protecting (the body) against pathogens. Its other main functions are insulation and temperature regulation, sensation, and synthesis of vitamin D and the protection of vitamin B folates.

Severely damaged skin will try to heal by forming scar tissue, often giving rise to discoloration and depigmentation of the skin.

Oily skin is caused by hormonal fluctuations in the body, which lead to a DHT sensitivity. This sensitivity means that the skin begins to lose moisture and essential fatty acids (linoleic acid in particular), causing thousands of skin cells to die, so the skin compensates for this loss of moisture by producing higher levels of oil.

Acne Vulgaris

Acne vulgaris (commonly called Acne) is a skin disease, caused by changes in the pilosebaceous units (skin structures consisting of a hair follicle and its associated sebaceous gland). Severe acne is inflammatory, but acne can also manifest in noninflammatory forms. Acne lesions are commonly referred to as pimples, spots, or zits.

Acne is most common during adolescence, affecting more than 85% of teenagers, and frequently continues into adulthood. For most people, acne diminishes over time and tends to disappear, or at least decrease, after one reaches his or her early twenties. There is, however, no way to predict how long it will take for it to disappear entirely, and some individuals will continue to suffer from acne decades later, into their thirties and forties and even beyond.

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