What Is an Accessory Organ?

Skin appendages are derived from the epidermis during embryogenesis and include hair, sebaceous glands, sweat glands, fingernails, etc. Skin appendages play an important role in maintaining normal skin function.

Basic Information

Chinese name

Skin accessory

Make up

Hair, sebaceous glands, sweat glands, fingernails

Features

Protect skin and mucous membranes, etc.

Skin appendage composition

1. In addition to the palms and soles, most of the human body has hair distribution. Hair is composed of hair shaft, hair root and hair follicle. The part embedded in the skin is called the hair root, and the part protruding outside the skin is called the hair shaft. The tubular sheath composed of epithelium and connective tissue wrapped around the hair root is called the hair follicle. The hair root and the lower end of the hair follicle are integrated into one body, called a hair bulb. The underside of the hair ball is depressed, and the connective tissue and blood vessels and neurites are called hair papillae. The thickness, length, density, and color of hair vary with the location, age, gender, physiological state, and race.
2. Sebaceous glands are present in most skins except for a few parts such as palms, soles of the feet, and the back of the feet. The sebaceous glands are located between the hair follicles and erector hair muscles, secrete sebum, and the ducts open on the surface of the hair follicles or skin. The sebum secreted by the sebaceous glands has a soft and protective effect on the skin and hair.
3. Sweat gland Sweat gland is a single curved tubular gland. The secretory part is thick and long, highly curved, and is located in the deep layer of dermis and subcutaneous tissue. The duct is slender and opens on the surface of the hair follicle or skin. Sweat glands can be divided into two types according to their structural characteristics, secretory properties and distribution locations, which are divided into large sweat glands and small sweat glands. The sweat glands are also called apocrine sweat glands, and their secretions are located in the armpits, areola, and perineum. They can secrete a viscous emulsion, which can produce a special odor after being broken down by bacteria. The small sweat gland is also called exocrine sweat gland. Its secretory part is located in the deep dermis or subcutaneous tissue. It consists of a single layer of short columnar gland cells. The small sweat glands are almost everywhere in the skin, and the secretion is a colorless, thin liquid.
4. Finger (Toenail) Fingernails (toenail) are located on the back of fingers or toes, and are composed of multiple layers of keratinocytes. The exposed part is called the deck, the part buried in the skin is called the nail root, the skin under the deck is the nail bed, and the skin folds around the deck are called nails, and the shallow groove between the sides of the nail body and the skin is called For Jiagou. The lower tissue behind the nail root is the nail matrix, which is the growth area of the nail.
When fingernails are removed, fingernails can still regenerate as long as the nail matrix is retained.

Skin appendage function

1. Hair can reduce head heat loss and protect the head from sun damage. Eyebrows and eyelashes protect the eyes from sunlight, dust and sweat. Nose hair can reduce the amount of dust and other foreign objects in the nasal cavity.
2. Sebaceous glands Sebaceous glands mainly secrete sebum, moisturize the skin and hair, prevent skin dryness, and also have bactericidal effects.
3. Sweat glands The sweat function of sweat glands has the effects of moistening the skin, regulating body temperature, affecting the content of water and inorganic salts in the body, and excreting some metabolites.
4. Finger (toe) nails can protect the last finger (toe), feel fine touch, and can reflect the health of the body.