peak bone mass

Examples of peak bone mass in the following topics:

• Osteoporosis

  • Weight-bearing exercise such as walking helps maintain bone strength.
  • Osteoporosis is a disease of the bones that leads to an increased risk of fracture.
  • In osteoporosis, the bone mineral density (BMD) is reduced, bone microarchitecture deteriorates, and the amount and variety of proteins in bone is altered.
  • The three main mechanisms by which osteoporosis develop are an inadequate peak bone mass (the skeleton develops insufficient mass and strength during growth), excessive bone resorption, and inadequate formation of new bone during remodeling.
  • Its main consequence is the increased risk of bone fractures.

• Bone Scans

  • Bone scans are a special type of nuclear scanning test that is often used to find bone cancer or bone inflammation.
  • Cells easily break free from the tumor mass and are carried in the lymph system to other areas of the body where they begin growing new tumors.
  • A bone scan is a nuclear scanning test to find certain abnormalities in bone that are triggering the bone's attempts to heal.
  • A nuclear bone scan is a functional test, which means it measures an aspect of bone metabolism or bone remodeling .
  • Nuclear bone scans are not to be confused with the completely different test often termed a "bone density scan," DEXA or DXA, which is a low exposure X-ray test measuring bone density to look for osteoporosis and other diseases where bones lose mass, without any bone re-building (osteoblastic) activity.

• Bone Repair

  • These processes culminate in a new mass of heterogeneous tissue that is known as the fracture callus.
  • The next phase is the replacement of the hyaline cartilage and woven bone with lamellar bone.
  • Substitution of the woven bone with lamellar bone precedes the substitution of the hyaline cartilage with lamellar bone.
  • This new lamellar bone is in the form of trabecular bone.
  • The remodeling process continues with substitution of the trabecular bone with compact bone.

• Stages of Bone Development

  • These cartilage poitns are responsible for the formation of the diaphyses of long bones, short bones, and certain parts of irregular bones.
  • Remodeling or bone turnover is the process of resorption followed by replacement of bone with little change in shape, and occurs throughout a person's life, long beyond the initial development of bone.
  • Approximately 10% of the skeletal mass of an adult is remodeled each year.
  • The bone remodeling period refers to the average total duration of a single cycle of bone remodeling at any point on a bone surface.
  • Bone tissue is removed by osteoclasts, and then new bone tissue is formed by osteoblasts.

• Exercise and Bone Tissue

  • If loading on a particular bone increases, the bone will remodel itself to provide the strength needed for resistance.
  • If the load on a bone decreases, the bone will become weaker due to turnover.
  • It is less metabolically costly to maintain and there is no stimulus for continued remodeling required to maintain bone mass.
  • In females, growth is characterized by increased estrogen levels and increased mass and strength of bone relative to that of muscle.
  • For these reasons, walking could be an appropriate approach to prevent osteoporosis and maintain bone mass.

• Aging and the Endocrine System

  • In the developing human body, GH from the anterior pituitary gland stimulates production and release of IGF-I by the liver, which is then transported in the blood to stimulate growth of muscle and bone.
  • Declines in pituitary GH secretion are associated with loss of skeletal muscle mass, increased adiposity, and other detrimental effects of aging in elderly adults.
  • With aging, a decrease in the amount of circulating GH and consequently IGF-I results in weaker bones with a low bone mineral density (BMD).
  • In addition to lower circulating amounts of IGF-I, the responsiveness of bone to this protein has been shown to decrease in animal models.
  • DHEA peaks in the mid-20's and then gradually declines with aging (termed adrenopause), potentially reaching just 5% of its original level.

• Clavicle

  • The clavicle or collar bone is a long, curved bone on the upper portion of the shoulder that connects with the scapula and the sternum.
  • The clavicle, or collarbone, is a slender s-shaped bone that extends between the sternum and the scapula and is located directly above the first rib.
  • The clavicle in males is typically thicker and longer than a female's clavicle to account for the larger muscle mass operating through it.

• Development of Joints

  • Movable joints are formed at the intersection of bones and are covered by cartilage, which allows them to move freely.
  • Articular cartilage is a flexible material found between bones at movable joints.
  • Cell division within cartilage occurs very slowly, so growth is not based on a mass increase of the cartilage itself.
  • The epiphysis is the rounded end of a long bone, at its joint with adjacent bone(s).
  • The region of the long bone that forms the joint is called pressure epiphysis.

• Ilium

  • The ilium is the uppermost and largest bone of the pelvis.
  • The ilium is the uppermost and largest bone of the pelvis.
  • In humans, bi-iliac width is an anatomical term referring to the widest measure of the pelvis between the outer edges of the upper iliac bones.
  • It is also used by anthropologists to estimate body mass.
  • The ilium is the uppermost bone of the pelvis and extends laterally.

• Types of Connective Tissue

  • Bone tissue is also called the osseous tissue.
  • It is mostly formed of calcium phosphate in the chemical arrangement termed calcium hydroxyapatite, which gives bones their rigidity.
  • The hard outer layer of bones is composed of compact bone tissue, so-called due to its minimal gaps and spaces.
  • This tissue gives bones their smooth, white, and solid appearance, and accounts for 80% of the total bone mass of an adult skeleton.
  • Filling the interior of the bone is the trabecular bone tissue (an open cell porous network also called cancellous or spongy bone), which is composed of a network of rod and plate-like elements that make the overall organ lighter and allow room for blood vessels and marrow.