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To allow motion, different bones are connected by joints. Cartilage prevents the bone ends from rubbing directly onto each other. Muscles contract to move the bone attached at the joint. There are, however, diseases and disorders that may adversely affect the function and overall effectiveness of the system.
A bone is a rigid organ [1] that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility.
The human foot evolved as a platform to support the entire weight of the body, rather than acting as a grasping structure (like hands), as it did in early hominids. Humans therefore have smaller toes than their bipedal ancestors. This includes a non-opposable hallux, which is relocated in line with the other toes. [7]
Gross anatomy has become a key part of visual arts. Basic concepts of how muscles and bones function and deform with movement is key to drawing, painting or animating a human figure. Many books such as "Human Anatomy for Artists: The Elements of Form", are written as a guide to drawing the human body anatomically correctly. [4]
It is composed of around 270 bones at birth – this total decreases to around 206 bones by adulthood after some bones get fused together. [1] The bone mass in the skeleton makes up about 14% of the total body weight (ca. 10–11 kg for an average person) and reaches maximum mass between the ages of 25 and 30. [2]
A skeleton is the structural frame that supports the body of most animals.There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal frame to which the organs and soft tissues attach; and the hydroskeleton, a flexible internal structure supported by the hydrostatic pressure of body fluids.
Wolff's law, developed by the German anatomist and surgeon Julius Wolff (1836–1902) in the 19th century, states that bone in a healthy animal will adapt to the loads under which it is placed. [1] If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading.
Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts. Both processes utilize cytokine (TGF-β, IGF) signalling.In osteology, bone remodeling or bone metabolism is a lifelong process where mature bone tissue is removed from the skeleton (a process called bone resorption) and new bone tissue is formed (a process called ossification or new bone formation).