A skeleton is a sturdy framework of about 206 bones that protects the body's organs, supports the body, provides attachment points for muscles to enable body movement, functions as a storage site for minerals such as calcium and phosphorus, and produces blood cells.
The skeletal system is a living, dynamic system, with networks of infiltrating blood vessels. Living mature bone is about 60% calcium compounds and about 40% collagen. Hence, bone is strong, hard and slightly elastic. All humans were born with over 300 bones but some bones, such as those in the skull and lower spine, fuse during growth, thereby reducing the number. Although mature bones consist largely of calcium, most bones in the skeleton of vertebrates, including humans, began as cartilage. Some animals, such as sharks and sting rays, retain their cartilaginous skeleton in adulthood. Cartilage is a type of connective tissue, and contains collagen and elastin fibers.
Individual bones meet at areas called joints and are held in place by connective tissue. Most joints, such as the elbow, are called synovial joints, for the synovial membrane which envelopes the joint and secretes a lubricating fluid. Cartilage lines the surface of many joints and helps reduce friction between bones. The connective tissues linking the skeleton together at the joints are tendons and ligaments. Ligaments and tendons are both made up of collagen, but serve different functions. Ligaments link bones together and help prevent dislocated joints. Tendons link bone to muscle.
Because the bones making up the human skeleton are inside the body, the skeleton is called an endoskeleton. Some animals, such as the crab, have an external skeleton called an exoskeleton.
There are 28 bones in the skull. Of these, 8 bones comprise the cranium and provide protection for the brain. In adults, these bones are flat and interlocking at their joints, making the cranium immobile. Fibrous joints, or sutures occur where the bony plates of the cranium meet and interlock. Cartilage-filled spaces between the cranial bones of infants, known as soft spots or fontanelles, allow t…
The appendicular skeleton joins with the axial skeleton at the shoulders and hips. Forming a loose attachment with the sternum is the pectoral girdle, or shoulder. Two bones, the clavicle (collar bone) and scapula (shoulder blade) form one shoulder. The scapula rest on top of the ribs in the back of the body. It connects to the clavicle, the bone which attaches the entire shoulder structure to the…
Bones may be classified according to their various traits, such as shape, origin, and texture. Four types are recognized based on shape. These are long bones, short bones, flat bones and irregular bones. Long bones have a long central shaft, called the diaphysis, and two knobby ends, called the epiphysis. In growing long bones, the diaphysis and epiphysis are separated by a thin sheet of cartilage…
Since most bone begins as cartilage, it must be converted to bone through a process called ossification. The key players in bone development are cartilage cells (chondrocytes), bone precursor cells (osteoprogenitor cells), bone deposition cells (osteoblasts), bone resorption cells (osteoclasts) and mature bone cells (osteocytes). During ossification, blood vessels invade the cartilage and transpor…
Even though bones are very strong, they may be broken, but fortunately, most fractures do heal. The healing process may be stymied if bones are not reset properly or if the injured person is the victim of malnutrition. Osteoprogenitor cells migrate to the site of the fracture and begin the process of making new bone (osteoblasts) and reabsorbing the injured bone (osteoclasts). With proper care, th…
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hi there i wanna know the effects this is for my betech sport and C.C.C
the school i go 2 in cambridge please write back ASAP cheers man :)
11 months ago
hey
hey
4 months ago
dont worry about that lad
6 months ago
kristine
rty6t7uy87
9 months ago
Sonia
heyyyyy idk how to do dis project bout skeletal systemm......u guys no how?
9 months ago
IDK
10 months ago
very informative
about 1 year ago
hello, iam 21 , female, my parent say that my bones are larger and so i look broader and little fat.. is that true tat bone shape differs from one to another??
about 1 year ago
i am here informing you that i would like join your website to gather information about health because iam health undergraduate
User Comments
almost 4 years ago
hi there i wanna know the effects this is for my betech sport and C.C.C
the school i go 2 in cambridge please write back ASAP cheers man :)
11 months ago
hey
hey
4 months ago
dont worry about that lad
6 months ago
kristine
rty6t7uy87
9 months ago
Sonia
heyyyyy idk how to do dis project bout skeletal systemm......u guys no how?
9 months ago
IDK
10 months ago
very informative
about 1 year ago
hello, iam 21 , female, my parent say that my bones are larger and so i look broader and little fat.. is that true tat bone shape differs from one to another??
about 1 year ago
i am here informing you that i would like join your website to gather information about health because iam health undergraduate
best regards
by mustaqim