Skin appendages

By the skin appendages include sweat and sebaceous glands, hair and nails.

Sweat glands (glandulae suderiferae) to represent a form of tubular glands, which lie end divisions, forming glomeruli, in the deepest layers of the dermis. They are located in the subcutaneous tissue at the border and subcutaneous tissue of the dermis and almost the entire body, except the red border of lips and penis. Especially numerous on the palms and soles. Sweat gland duct (ductus sudoriferus) in a spiral penetrates all layers of the skin, the epidermis and in the open on its surface, sometimes sweat (porus sudoriferus). All the sweat glands secrete fluid secret, resulting in the process of thermoregulation of the body and elimination of a harmful metabolic products. Secret, secreted by glands, which lie in the axillae, inguinal folds, pubic and breast nipples, has a characteristic odor.

The sebaceous glands (glandulae sebaseae) - in the form of simple branched alveolar glands, located on the entire surface of the body except the palms and soles. Ducts of the sebaceous glands open into hair sac - follicle - and on the surface of the skin in areas where hair is missing: the palms, soles, red border of the lips, nipples, inner surface of the hole anus, etc. Each follicle is suitable from 1 to 3 ducts. The sebaceous glands secrete sebum, which prevents drying of skin and hair, providing them with a fatty oil.

Hair (pili) are derived the epidermis and are the elastic horny filament. They cover the whole body except the palms, the lateral surfaces of the fingers, soles, red border of lips, the labia minora, glans penis and the inner leaf of the foreskin.

Hair divided into primary, which are delicate baby down, the secondary - the thicker vellus body hair, hair, eyebrows and eyelashes, and tertiary, appearing at puberty: the hair the face (beard and mustache), pubic hair, underarm hair, hair, nostrils and external auditory canal.

The hair itself consists of a medulla, which is absent in baby hair, cortical substance constituting the bulk of the hair and contains the pigment, that may influence its color, as well as of the cuticle covering the outer surface of the hair.

Hair is divided into the hair shaft (scapus pili), located above the surface of the skin and the hair root (radix pili), which occurs in the skin. The root is located at an angle to the skin and ends with a small seal, are called the hair follicle (bulbus pili). Below it grows into a papilla of hair (papilla pili). The root itself is located in the root sheath, formed by a layer of the epidermis of the sprout. Root sheath, in turn, is located in the follicle, or a bag of hair (follicula pili).

The growth of the hair-producing cells provided, covering the papilla. Upon termination of supply of these cells no longer new form, the bulb dies, separates from the papilla and the hair falls out.

Nails (unguis), as well as hair, - derivatives of the epidermis, which are dense horny plates. They have a convex shape and are located on the back of the distal phalanges of fingers and toes. The plates are formed by tightly contiguous with horny scales.

The nail is located in the nail bed (matrix unguis), formed by connective tissue of the dermis and epidermis layer of the sprout and limited on the sides and rear of the bed furrow (sulcus matricis unguis). Above the groove is roll the nail (vallum). The surface of the nail bed is a series of longitudinal scallop beds (cristae matricis unguis).

In the isolated body of the nail the nail (corpus unguis), the edge of the nail and the nail root (radix unguis). The latter is located in the rear groove of the bed, which is significantly deeper than the lateral grooves. The edges of the nail are four: the free edge (margo liber), protruding over the end of the distal phalanx of the hidden edge (margo occultus), located next to the root of the nail, and two side edges (margines laterales).

The growth of horny scales is due to the growth layer of the epithelium of nail bed. The most highly developed it at the root of the nail, and even shine through the nail plate. This area is called the crescent (lunula).

List of Abbreviations

a., aa. — arteria, arteriae (artery, the artery)

lig., ligg. — ligamentum, ligamenta (ligament, the ligaments)

m., mm. — musculus, musculi (muscle, the muscle)

n., nn. — nervus, nervi (nerve, the nerve)

r., rr. — ramus, rami (branch)

s. — seu (or)

v., vv. — vena, venae (vienna)