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Current Congress. Committees of Interest. Legislative Resources. Recent Public Laws. Search Search. Cancer Information Summaries. Sweat glands, also called sudoriferous glands, are simple tubular glands found almost everywhere on our body. Each sweat gland is made up of two portions:. The secretory portion is found in the dermis, the middle layer of the skin. The secretory portion of a sweat gland is a twisted and coiled tube that has an opening at its very top.
It is in the coiled secretory portion of the sweat gland where the sweat is actually produced. The excretory duct moves from the secretion portion, through the dermis, and into the topmost layer of the skin, the epidermis, where it opens up at the surface of our skin.
Human Skin: Cross sectional image of skin showing a sweat gland and a sebaceous gland. However, some sebaceous gland ducts open directly onto our skin surface such as at the corner of the mouth and the glans penis. Regardless, the secretion of sebum out of the gland is helped along by the contraction of the arrector pili muscle. While the sebaceous glands are present just about all over the skin, they are notably absent on the palms of the hands and the soles of the feet.
The sebum being excreted by your body today began production around 8 days ago. Sebaceous Gland: Schematic view of a hair follicle with sebaceous gland. Sebaceous glands are involved in numerous conditions. During puberty, various hormones cause them to produce a lot of sebum and this therefore contributes to oily skin. If a duct of a sebaceous gland is clogged with sebum, a whitehead results. If this material is allowed to dry and oxidize, it will become darker, forming a blackhead.
If a sebaceous gland becomes infected, moderate and severe forms of acne are the result. The glands lining the ear canal that produce earwax cerumen are called ceruminous glands. They are modified sebaceous glands. The fingernail is an important structure made of keratin. The fingernail generally serves two purposes: it acts as a protective plate and enhances sensation of the fingertip.
Nails can also help grasp small things. The protection function of the fingernail is commonly known, but the sensation function is equally important. The fingertip has many nerve endings in it that allow it to receive volumes of information about the objects we touch.
The nail acts as a counterforce to the fingertip, providing even more sensory input when an object is touched.
Nails grow from the nail bed continuously but they slow down their growth rate with age, poor nutrition, or poor circulation. The nail sinus sinus unguis is where the nail root is—at the base of the nail underneath the skin.
It originates from the actively growing tissue below, the matrix. The root of the fingernail is also known as the germinal matrix. This portion of the nail is actually beneath the skin, behind the fingernail, and extends several millimeters into the finger.
The fingernail root produces most of the volume of the nail and the nail bed. This portion of the nail does not have any melanocytes, or melanin-producing cells. The edge of the germinal matrix is seen as a white, crescent shaped structure called the lunula. The nail bed is a part of the nail matrix called the sterile matrix. It extends from the edge of the germinal matrix, or lunula, to the hyponychium.
The nail bed contains the blood vessels, nerves, and melanocytes, or melanin-producing cells. Any use of this site constitutes your agreement to the Terms and Conditions and Privacy Policy linked below.
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