Medical research

Study charts developmental map of inner ear sound sensor in mice

A team of researchers has generated a developmental map of a key sound-sensing structure in the mouse inner ear. Scientists at the National Institute on Deafness and Other Communication Disorders (NIDCD), part of the National ...

Oncology & Cancer

Developing microbeam radiation therapy (MRT) for inoperable cancer

An innovative radiation treatment that could one day be a valuable addition to conventional radiation therapy for inoperable brain and spinal tumors is a step closer, thanks to new research led by University of Saskatchewan ...

Medical research

New insights provide hope for new hair growth in adults

We are born with all the hair follicles that we will ever have in our lives, because after birth the skin loses the ability to create new hair follicles. If our skin is severely damaged it cannot form new hair follicles or ...

Psychology & Psychiatry

Hair in "stress": analyse with care

Similar to humans, wild animals' reaction to disturbance is accompanied by releasing hormones, including cortisol. To understand the impact of various stress factors on wildlife—for example, competition for food, encounters ...

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Hair

Hair is a protein filament that grows through the epidermis from follicles deep within the dermis. The fine, soft hair found on many nonhuman mammals is typically called fur; wool is the characteristically curly hair found on sheep and goats. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class. Although other non-mammals, especially insects, show filamentous outgrowths, these are not considered "hair" in the scientific sense. So-called "hairs" (trichomes) are also found on plants. The projections on arthropods such as insects and spiders are actually insect bristles, composed of a polysaccharide called chitin. There are varieties of cats, dogs, and mice bred to have little or no visible fur. In some species, hair is absent at certain stages of life. The main component of hair fiber is keratin.

The hair can be divided into three parts length-wise, (1) the bulb, a swelling at the base which originates from the dermis, (2) the root, which is the hair lying beneath the skin surface, and (3) the shaft, which is the hair above the skin surface. In cross-section, there are also three parts, (1) the medulla, an area in the core which contains loose cells and airspaces (2) the cortex, which contains densely packed keratin and (3) the cuticle, which is a single layer of cells arranged like roof shingles.

This text uses material from Wikipedia, licensed under CC BY-SA