Dictionary > Keratin

Keratin

Definition
noun, plural: keratins
One of the fibrous structural proteins, and is a constituent of hair, nails, skin, feathers, hooves, horns, etc.
Supplement
Scleroproteins or the fibrous proteins are one of the three major types of proteins; the other two are spheroproteins and membrane proteins. Scleroproteins are characterized by their long protein filaments. They act as structural proteins. They are usually water-insoluble. Some of the scleroproteins are keratin, collagen, elastin, and fibroin.
Keratins are fibrous structural proteins that constitute various biological structures such as hair, nails, skin, feathers, hooves, horns, etc. They are made up of coiled polypeptide chains and when they combine they form supercoils.
Keratins protect epithelial cells from damage. Skin cells that are constantly exposed to pressure and rubbing leads to the formation of calluses. The skin thickens and the epidermal cells undergo cornification. Cornification is a process in which a keratinized layer of epidermis forms and serves as an epidermal barrier. During cornification, keratin fills up the cell resulting in the loss of cytoplasmic organelles and the cessation of metabolism. Ultimately, the fully keratinized cells undergo a programmed cell death.
Word origin: Greek keras (horn) + –in
See also:

Related term(s):

  • keratinization
  • Related form(s):

    • keratinous (adjective, relating to keratin; horny)


    You will also like...

    Direct and indirect physiologic effects of growth hormone
    Animal Growth Hormones

    Hormones are produced in the endocrine glands of animals. The pituitary gland and hypothalamus are the most impor..

    Regulation of Biological Systems
    Regulation of Biological Systems

    Regulation of Biological Systems tutorials are focused on the modulation of biological systems from cell to population l..

    Kidneys
    Kidneys and Regulation of Water and Inorganic Ions

    The kidneys are responsible for the regulation of water and inorganic ions. Read this tutorial to learn about the differ..

    human brain structure
    The Conscious & Unconscious Nervous System

    This tutorial elaborates on how the nervous system works, particularly at the tissue level of the brain. There are three..

    Early Mammals on Earth
    Early Mammals on Earth

    The Earth's ecosphere was rapidly changing and throwing up a wide range of ecological niches that new adaptive organisms..

    Electromagnetic spectrum of a brain
    Sleep and Dreams – Neurology

    While learning and intelligence are associated with the functions of a conscious mind, sleep and dreams are activities o..

    Related Articles...

    No related articles found

    See all Related Topics