Apocrine sebaceous

From Wolff K, Johnson RA. Disorders of sebaceous and apocrine glands. Fitzpatrick s Color Atlas Synopsis of Clinical Dermatology. 5th ed. New York McGraw-Hill, 2005 5.)... 

Skin appendages can be distinguished into hair follicles with their associated sebaceous glands, eccrine sweat glands, apocrine sweat glands, and nails. 

FIGURE 3.7 Elements of mammalian skin glands. S, sebaceous gland A, apocrine gland E, eccrine gland M, errector pili muscle H, hair follicle. (From Albone, 1984.)... 

Testosterone stimulates secretion in sebaceous and apocrine glands in rabbits, rats, guinea pigs, and hamsters, while estrogen in most cases inhibits secretion. Progesterone tends to be neutral (reviewed by Ebling, 1977). 

FIGURE 6.7 The double scent mark of the brown hyena. The black mark on top originates from apocrine glands and the white mark from separately located sebaceous glands. (Redrawn from Mills etal., 1980.)... 

The appendages of skin are hair follicles, sebaceous glands, eccrine and apocrine sweat glands, hair, nails, and arrector pili muscles. 

Earwax is a normal secretion. The main component, cerumen, is a protective wax-like substance with antifungal and antibacterial properties that traps particles and so helps keep the ears clean. Earwax is formed when cerumen secreted by the sebaceous and apocrine glands in the external auditory canal combines with sebum, exfoliated skin cells, sweat, hair and retained dust. 

Appendageal structures commonly found within the skin are the hairs, hair follicles, associated sebaceous glands, apocrine and eccrine sweat glands, and arrector pili muscles. Hairs are formed by epidermal invaginations. These keratinized structures traverse the dermis and may extend into the hypodermis. The free part of the hair above the surface of the skin is the hair shaft, and the part deep within the dermis is the hair root, which forms an expanded knob-like structure called the hair bulb. This is composed of a matrix of epithelial cells in different stages of differentiation. Hair is composed of three concentric epithelial cell layers the outermost thin cuticle, a densely packed keratinized cortex, and a central medulla of cuboidal cells. The hair follicle consists of four major components (1) internal root sheath (internal root sheath cuticle, granular layer, pale epithelial layer) (2) external root sheath (several layers similar to the epidermis) (3) dermal papilla (connective tissue) and (4) hair matrix (comparable to the stratum basale of the epidermis). 

However, in the light of multiple experimental findings based upon more accurate and precise techniques, this model seems to be oversimplified since it does not take into account the potential transfer of drugs from sweat, sebaceous and apocrine gland secretions, nor the external contamination even via deep compartments located in the skin surrounding the hair follicle. 

Hair follicles and their associated sebaceous glands (pilosebaceous glands), eccrine glands, apocrine glands, and finger and toenails are all considered skin appendages. Hair follicles are found everywhere within the skin except for the soles of the feet, the palms of the hand, the red portion (vermilion border) of the lips, and the external genitalia. All are formed from fetal epidermal cells. Hair differs markedly in its prominence from place to place over the body. Delicate primary hair is found on the fetus secondary hair or down covers the adult forehead terminal hair ordinarily blankets the scalp and is found as pubic... 

Fitzpatrick TB, Johnson RA, WoUf K, et al. Disorders of apocrine and sebaceous glands. In Color Atlas and Synopsis of Qinical Dermatology, Common Serious Diseases, 4th ed. New York, McGraw-Hill, 2001 2—7. 

Human skin is known to be colonized by a huge number of bacteria that live as commensals on the surface and within the follicles. It is possible to describe the basic pattern of colonization of a healthy human skin. Variations of this pattern may be observed dry skin supports a low level of colonization, while moist areas provided with sebaceous and apocrine glands are the most heavily populated. The resident aerobic flora consists of gram-positive cocci of staphylococcus and micrococcus, and a variety of gram-positive rods, mainly corynebacterium. The main anaerobic residents are propionibacteria, which are localized in the follicles of the sebaceous glands of adults. The microbial flora, usually localized on the skin, appears to have several functions, the most important of which is probably the defense against pathogenic... 

Prostate, apocrine and sebaceous glands, skin, oral mucosa... 

Figure 1.3 Light micrograph of pig skin depicting the stratum corneum (SC), hair follicle (HF), sebaceous glands (SG), apocrine glands (A), and dermis (D). lOOx...

The excretory portion in the skin involves secretion from the sebaceous glands and the apocrine and eccrine sweat glands. 

---