Skin Accessories
Cutaneous Glands
Sebaceous glands are exocrine glands that produce sebum (oil) to lubricate the skin, prevent brittle hair and kill bacteria on the surface of the skin. Most sebaceous glands have ducts that empty into hair follicles, while others open directly onto the skin. These glands are activated at puberty. Sebaceous glands will cause white heads & black heads if clogged.
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Sudoriferous glands are sweat glands. They produce sweat and are widely distributed throughout the skin. Eccrine glands are open to pores on the skin's surface and produce sweat to aid in thermoregulation, excrete waste and maintain acid surface to inhibit growth of bacteria. Apocrine glands have ducts that empty into hair follicles and only begin to function at puberty. They release sweat that also contains fatty acids & proteins. The odor associated with sweat is actually from the bacteria.
Hair
Hair is produced by the hair follicle, leaving the root enclosed in the follicle. Hair is made from keratinized epithelial cells. Melanin provides the pigment for hair color. Balding and/or graying occurs with aging. While both are genetically determined, other factors may contribute including drugs and emotional stress.
Alongside the hair follicle is the arrestor pili muscle. This is a smooth muscles that pulls hair upright when a person is cold or frightened.
Alongside the hair follicle is the arrestor pili muscle. This is a smooth muscles that pulls hair upright when a person is cold or frightened.
Nails
Nails are simply scale-like modifications of the epidermis which have been heavily keratinized. The stratum basale (site of growth) extends below the nail bed. Their lack of melanin makes them colorless.
Nerves
In the dermis there are nerves that also innervate the epidermis. All of these nerve receptors function to provide input about the world around us, in order to maintain homeostasis. There are nerves for pain, temperature, light touch and deep pressure. These nerves are not evenly distributed throughout the body - their distribution ratios are dependent on location on the body.