Dictionary > Bone


noun, plural: bones
The rigid organ comprised of bone tissues, and forms the skeleton of most vertebrates
The bone is an organ that forms the skeleton of vertebrates. It is formed from bone tissues, which are mineralized connective tissues. Apart from bone tissues, other types of tissues in bone are marrow, endosteum, periosteum, nerves, blood vessels, and cartilage. The fundamental functional unit is called the Haversian system (or osteon).
There are different types of bones based on their morphological features: (1) long bones (e.g. bones of the limbs), (2) short bones (e.g. tarsals and carpals), (3) flat bones (e.g. cranium, ilium, sternum, and rib cage), (4) irregular bones (e.g. vertebrae), and (5) sesamoid bones (e.g. patella, pisiform of the wrist, lenticular process of the incus, first metacarpal bone, and first metatarsal bone).
The major functions of bones are to provide structural support (act as the body’s framework) and to protect internal organs. In humans, the bone marrow of cancellous bone is the site of hematopoiesis. The bone also serves as a reservoir of minerals, e.g. calcium and phosphorus.
The bone is constantly being made and replaced in the process called remodeling.

See also:

  • osteoblast
  • osteocyte
  • osteoclast
  • bone matrix
  • skeletal system
  • Haversian system
  • Related term(s):

    You will also like...

    Biological Viruses
    Biological Viruses

    Viruses possess both living and non-living characteristics. This unique feature distinguishes them from other organisms...

    Protein (illustration)
    Protein Variety

    The sequence of amino acids determines the type of protein. Protein is synthesized according to the sequence of nucleoti..

    Golgi apparatus (3-D illustration)
    Role of Golgi Apparatus & Endoplasmic Reticulum in Protein Synthesis

    The endoplasmic reticulum and Golgi apparatus are the organelles involved in the translation step of protein synthesis a..

    Plant meristem
    Plant Meristems and Growth

    In plants, growth occurs in meristems, which are the site of repeated cell division of unspecialized cells. These cells ..


    The circulatory system is key to the transport of vital biomolecules and nutrients throughout the body. Learn about the ..

    Sensory systems
    Sensory Systems

    A sensory system is a part of the nervous system consisting of sensory receptors that receive stimuli from the internal ..