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The pressure sensor of the Venus flytrap

All plant cells can be made to react by touch or injury. The carnivorous Venus flytrap (Dionaea muscipula) has highly sensitive organs for this purpose: sensory hairs that register even the weakest mechanical stimuli, amplify ...

Black holes gain new powers when they spin fast enough

General relativity is a profoundly complex mathematical theory, but its description of black holes is amazingly simple. A stable black hole can be described by just three properties: its mass, its electric charge and its ...

Algorithm could identify disease-associated genes

ITMO University's bioinformatics researchers have developed an algorithm that helps to assess the influence of genes on processes in the human body, including the development of disease. The research was published in BMC ...

Scientists use bacteria as micro-3-D printers

A team at Aalto University has used bacteria to produce intricately designed three-dimensional objects made of nanocellulose. With their technique, the researchers are able to guide the growth of bacterial colonies through ...

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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.

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