Sebaceous and Sweat Gland Functions in Skin Health

Topic: Sebaceous Glands and Hair Follicles

Sebaceous glands, associated with hair follicles, secrete sebum (oil). These glands are shaped like lobes, constituted by many cells that discharge their secretion. Sebum secretion mixes with perspiration, forming the epicutaneous emulsion. They are surrounded by a basal epidermal membrane and separated from the lobes by connective tissues. They are not supplied by ducts but are surrounded by many blood vessels.

Factors Influencing Sebum Secretion:

• Abundance: High in the middle region of the face, scalp, and upper back.
• Age: Production starts at puberty and increases with age until about 50 years, when it begins to decrease.
• Sex: Males produce more sebum.

Gladulas Sweat (Sweat Glands)

Sweat glands are localized deep in the dermis and also in the hypodermis. They discharge their secretions through a large duct.

Eccrine Glands (GSEcrinas):

• They pour their secretion out onto the skin surface.
• They are surrounded by blood vessels at the glomerulus.
• They are found everywhere except the nail bed or lips, and are common throughout the soles and palms.
• Sweat Composition: Composed of 99% water, with dissolved inorganic and organic substances.

Apocrine Glands (GSApocrinas):

• They shed perspiration secretion into the hair follicles, where the secretion mixes with the sebaceous sebum.
• They are located in the armpits, anogenital region, and mammary areola.
• The glomerulus is located in the hypodermis.
• Sweat Composition: This sweat differs; it is milky and viscous, with a neutral pH. This allows bacteria on the skin surface to decompose it, resulting in an unpleasant odor upon production (the sweat itself is odorless).

Epicutaneous Emulsion

This is a hydrolipidic film that covers the entire skin surface. It forms from the mix of secretions from sebaceous glands and sweat, joining with sloughed corneal epidermal cells. It protects and regulates skin hydration and permeability.

Phases:

1. Aqueous Phase (f. acuosa): Sweat + dissolved substances.
2. Oily Phase (f. oleosa): Tallow (sebum) + substances dissolved in it.
3. Emulsifying Phase (f. emulgente): The union of the two previous phases, which gives stability to the mixture.

Skin Hydration States

Hyperhydrated Skin (A/O):

Increased perspiration secretion, normal sebaceous secretion, and corneal extract saturated with water. The skin appears smooth, shiny, wet, and cold to the touch. It does not shed easily, tolerates the sun well, tolerates adverse weather conditions, and tolerates normal soap.

Dry Skin (DRIED FAT):

Insufficient sebum secretion combined with low sudoral (sweat) output. The corneum lipid extract is dehydrated and hydrophilic. The skin appears bright and fissured, thick, dry, rough, and shows early aging. It exhibits desquamation, has moderate sun tolerance, is sensitive to extreme atmospheric conditions, and does not tolerate soap.