What is hair that lacks pigment?
It is well known that gray hair results from a reduction of pigment, while white hair has no pigment, but why this happens remains somewhat of a mystery. Initially, hair is white. It gets its natural color from a type of pigment called melanin.
Which type of cutaneous receptor is specialized for the reception of touch or light pressure?
Meissner receptors detect light touch. Pacinian corpuscles perceive deep pressure and vibrational changes. Ruffini endings detect deep pressure and stretching of the skin’s collagen fibers. Free nerve endings located in the epidermis respond to pain, light touch, and temperature variations.
Which of the following is the protein found in the epidermis that is responsible for toughening the skin?
Keratinocytes produce keratin, a tough, protective protein that makes up the majority of the structure of the skin, hair, and nails. The squamous cell layer is the thickest layer of the epidermis, and is involved in the transfer of certain substances in and out of the body.
What is Poliosis?
Poliosis is when a person is born with or develops a patch of white or gray hair while otherwise maintaining their natural hair color. It can affect both children and adults. You’ve probably seen people with poliosis in movies, on stage, or on TV.
Is Poliosis genetic?
Poliosis occurs in several genetic syndromes such as piebaldism, Waardenburg syndrome, neurofibromatosis type I, and tuberous sclerosis. It can also occur in conditions such as vitiligo, Vogt–Koyanagi–Harada disease, alopecia areata, sarcoidosis, and in association with neoplasms and some medications.
Is often called the epidermal layer?
The epidermis is the outermost of the three layers that make up the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water released from the body into the atmosphere through transepidermal water loss.
What do Vellus hairs lack?
Each hair follicle contains a gland that secretes sebum, an oil that lubricates the skin and hair. However, unlike terminal hair, vellus hair does not typically have a medulla. The medulla is a portion of the hair’s core that strengthens it, allowing it to grow longer.