Figure 6.1 Child Looking in ~ Bones Bone is a living tissue. Uneven the bones of a fossil do inert by a process of mineralization, a child’s bones will continue to grow and also develop while contributing to the assistance and function of other body systems. (credit: James Emery)


After examining this chapter, you will be may be to: 

List and describe the functions of bonesDescribe the classes of bonesDiscuss the process of bone formation and developmentExplain exactly how bone repairs chin after a fractureDiscuss the effect of exercise, nutrition, and hormones on bone tissueDescribe how an imbalance of calcium can influence bone tissue

Bones make an excellent fossils. If the soft organization of a once living organism will decay and also fall away over time, bone organization will, under the right conditions, experience a process of mineralization, effectively turning the bone to stone. A well-preserved fossil skeleton can provide us a great sense the the size and also shape of one organism, simply as her skeleton helps to define your size and shape. Unequal a fossil skeleton, however, her skeleton is a structure of living tissue that grows, repairs, and renews itself. The bones in ~ it space dynamic and facility organs that serve a variety of important functions, consisting of some crucial to keep homeostasis.

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through the finish of this section, you will certainly be able to:Define bone, cartilage, and the bones systemList and describe the functions of the skeleton system

Bone, or osseous tissue, is a hard, dense connective tissue that develops most the the adult skeleton, the support framework of the body. In the locations of the skeleton wherein bones relocate (for example, the ribcage and joints), cartilage, a semi-rigid type of connective tissue, gives flexibility and smooth surfaces for movement. The skeletal system is the body device composed of bones and also cartilage and performs the following critical functions because that the human body:

supports the bodyfacilitates movementprotects inner organsproduces blood cellsstores and also releases minerals and also fat

Support, Movement, and Protection

The most apparent functions that the skeletal mechanism are the pistol functions—those visible by observation. Simply by looking in ~ a person, you have the right to see how the skeleton support, facilitate movement, and also protect the human being body.

Just together the stole beams that a building carry out a frame to support its weight, the bones and cartilage of her skeletal mechanism compose the scaffold the supports the remainder of your body. Without the skeletal system, you would certainly be a limp mass of organs, muscle, and skin.

Bones additionally facilitate movement by serving together points of attachment for her muscles. While some bones just serve as a assistance for the muscles, others additionally transmit the forces developed when your muscles contract. From a mechanical suggest of view, skeletal act together levers and also joints serve as fulcrums (Figure 6.2). Unless a muscle spans a joint and also contracts, a bone is no going come move. For information on the communication of the skeletal and also muscular systems, the is, the musculoskeletal system, seek extr content.


Figure 6.2 Bones assistance Movement Bones act as levers once muscles expectancy a joint and also contract. (credit: Benjamin J. DeLong)

Bones additionally protect internal organs native injury by extending or surrounding them. For example, your ribs defend your lungs and also heart, the skeleton of your vertebral pillar (spine) protect your spinal cord, and the bones of her cranium (skull) protect your brain (Figure 6.3).


Figure 6.3 Bones safeguard Brain The cranium fully surrounds and also protects the mind from non-traumatic injury.



An orthopedist is a medical professional who specialization in diagnosing and also treating disorders and injuries concerned the musculoskeletal system. Part orthopedic problems can it is in treated through medications, exercises, braces, and also other devices, however others might be finest treated with surgical procedure (Figure 6.4).


Figure 6.4 Arm Brace An orthopedist will periodically prescribe the use of a brace the reinforces the basic bone framework it is being provided to support. (credit: Juhan Sonin)

While the origin of words “orthopedics” (ortho- = “straight”; paed- = “child”), literally way “straightening of the child,” orthopedists have the right to have patient who selection from pediatric come geriatric. In recent years, orthopedists have even performed prenatal surgical procedure to correct spina bifida, a congenital defect in i beg your pardon the neural canal in the spine of the fetus stops working to close fully during embryologic development.

Orthopedists generally treat bone and also joint injuries yet they also treat various other bone problems including curvature of the spine. Lateral curvatures (scoliosis) deserve to be severe enough to slip under the shoulder tongue (scapula) forcing that up as a hump. Spinal curvatures can also be excessive dorsoventrally (kyphosis) resulting in a hunch ago and thoracic compression. These curvatures often show up in preteens as the result of bad posture, abnormal growth, or indeterminate causes. Mostly, lock are easily treated by orthopedists. As human being age, built up spinal tower injuries and diseases prefer osteoporosis can also lead come curvatures of the spine, for this reason the stooping you sometimes see in the elderly.

Some orthopedists sub-specialize in sports medicine, which addresses both straightforward injuries, such as a sprained ankle, and complex injuries, such together a take it rotator cuff in the shoulder. Therapy can variety from exercise to surgery.

Mineral Storage, power Storage, and Hematopoiesis

On a metabolic level, bone tissue performs several critical functions. Because that one, the bone matrix acts as a reservoir because that a variety of minerals crucial to the to work of the body, specifically calcium, and phosphorus. This minerals, integrated into bone tissue, can be released back into the bloodstream to preserve levels needed to support physiological processes. Calcium ions, because that example, are crucial for muscle contractions and also controlling the flow of various other ions associated in the transmission of nerve impulses.

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Bone likewise serves as a website for fat storage and also blood cell production. The softer connective organization that filling the internal of many bone is described as bone marrow (Figure 6.5). There room two types of bone marrow: yellow marrow and red marrow. Yellow marrow contains adipose tissue; the triglythrade stored in the adipocytes that the tissue deserve to serve together a resource of energy. Red marrow is where hematopoiesis—the manufacturing of blood cells—takes place. Red blood cells, white blood cells, and platelets room all produced in the red marrow.


Figure 6.5 Head the Femur mirroring Red and Yellow Marrow The head the the femur contains both yellow and also red marrow. Yellow marrow stores fat. Red marrow is responsible for hematopoiesis. (credit: alteration of work-related by “stevenfruitsmaak”/Wikimedia Commons)