How does skeletal system maintain homeostasis

Because this condition is genetic, patients are asked prior to surgery if there is a family history of such problems occurring. Physical training alters the appearance of skeletal muscles and can produce changes in muscle performance. Conversely, a lack of use can result in decreased performance and muscle appearance. As you learned earlier, mature muscle cells grow from hypertrophy, not cell division.

The loss of structural proteins and muscle mass occurs during atrophy. Cellular components of muscles can also undergo changes in response to changes in muscle use. Although atrophy due to disuse can often be reversed with exercise, muscle atrophy that comes with age is irreversible.

This is why even highly trained athletes succumb to declining performance with age, although extensive training may slow the decline. This is especially noticeable in sports that require an explosion of strength and power over a very short period of time. Examples of these kinds of sports include sprinting, competitive weight lifting, gymnastics and diving. The effects of age are less noticeable in endurance sports such as marathon running or long-distance cycling.

Age-related muscle atrophy is called sarcopenia. As muscles age, muscle fibers die, and they are replaced by connective tissue and adipose tissue. Because those tissues cannot contract as muscle can, muscles lose the ability to produce powerful contractions. The decline in muscle mass causes a loss of strength, including strength required for posture and mobility.

This may be caused by a reduction in the proportion of FG fibers that hydrolyse ATP quickly to produce short, powerful contractions. Muscles in older people sometimes possess greater numbers of SO fibers, which are responsible for longer contractions and do not produce powerful movements.

There may also be a reduction in motor units, resulting in fewer fibers being stimulated and less muscle tension being produced. Some athletes attempt to boost their performance by using various agents that may enhance muscle performance.

Anabolic steroids are one of the more widely known agents used to boost muscle mass and increase power output.

Anabolic steroids are a form of testosterone, a male sex hormone that stimulates muscle formation, leading to increased muscle mass. They have been used by athletes in many sports, but sprinting is one sport in which the effects of steroids are readily apparent.

Because a meter dash can last less than 10 seconds, incredible amounts of power need to be created by the muscles. It consists of two halves that are fused together in adults. Each half consists of three bones: the ilium, pubis, and ischium. Osseous tissue is the main tissue in bones. It is a type of connective tissue consisting mainly of a collagen matrix that is mineralized with calcium and phosphorus crystals. Why are bones hard, but not brittle?

Bones are hard but not brittle because they are made of a combination of flexible collagen and mineral crystals. Compare and contrast the compact and spongy bone.

The two main types of osseous tissue are compact bone tissue and spongy bone tissue. Both types consist of the same kinds of cells, but the cells have different arrangements in the two types of bone.

As a result, compact bone is smooth and dense, whereas spongy bone is porous and light. Compact bone makes up the outer layer of bones, whereas spongy bone is found inside many bones. What non-osseous tissues are found in bones? Non-osseous tissues found in bones include nerves, blood vessels, bone marrow, and periosteum.

List four types of bone cells and their functions. Four types of bone cells are osteoblasts, which form new organic bone matrix and mineralize it; osteoclasts, which break down bone; osteocytes, which regulate the formation and breakdown of bone; and osteogenic cells, which form new bone cells.

Identify six types of bones. Give an example of each type. The six types of bones are long bones such as limb bones, short bones such as wrist bones, sesamoid bones such as the patella, sutural bones in skull sutures, and irregular bones such as vertebrae. Self-marking Compare and contrast yellow bone marrow and red bone marrow. Sample answer: Yellow and red bone marrow are both found in the marrow cavity of bones, but yellow marrow is mostly fat and red marrow produces blood cells.

All marrow in newborns is red, but much of it changes to yellow marrow in adults. Which type of bone cell divides to produce new bone cells? Where is this cell type located? Osteogenic cells, which are located in the periosteum covering the bone.

Where do osteoblasts and osteocytes come from? How are they related to each other? Osteoblasts are produced by osteogenic cells.

Osteocytes, in turn, arise from osteoblasts that have become trapped in bone matrix. Which type of bone is embedded in tendons?

Sesamoid bone. Early in the development of a human fetus, the skeleton is made almost entirely of cartilage. The relatively soft cartilage gradually turns into hard bone in the process called ossification.

It begins at a primary ossification centre in the middle of bone and later also occurs at secondary ossification centres in the ends of bone. Ossification of some bones continues through childhood, until the late teens or early twenties when skeletal maturity occurs. After that, bones can no longer grow in length because the areas of ossification have met and fused.

Describe the process of bone remodeling. When does it occur? Bone remodeling is the process in which osteoclasts resorb bone and osteoblasts make new bone to replace it. It occurs continuously throughout life, with about ten per cent of bone mass being remodeled each year in adults. What purposes does bone remodeling serve? Bone remodeling serves several purposes.

It shapes the skeleton, repairs tiny flaws in bones, and helps maintain mineral homeostasis in the blood. Define bone repair. How long does this process take? Bone repair is the natural process in which a bone repairs itself following a bone fracture. This process may take several weeks. Explain how bone repair occurs. In the process of bone repair, periosteum the connective tissue covering bone produces precursor cells that develop into osteoblasts.

Then the osteoblasts form new bone matrix to heal the fracture. Identify factors that may affect bone repair. Bone repair may be affected by diet, age, pre-existing bone disease, or other factors. Self-marking If there is a large region between the primary and secondary ossification centres in a bone, is the person young or old? If there is a large region between the primary and secondary ossification centres in a bone, the person is young, mostly likely well under 18 years of age.

This is because as a person grows older, the primary and secondary ossification centres grow towards each other and eventually meet and fuse around the ages of 18 to If bones can repair themselves, why are casts and pins sometimes necessary in the process? Sample answer: Bones can repair themselves, but casts and pins are sometimes needed to hold the pieces of the broken bone together in the right positions so that they can fuse together correctly.

When calcium levels are low, which type of bone cell causes the release of calcium to the bloodstream? Which tissue and bone cell type are primarily involved in bone repair after a fracture? After a bone fracture, the periosteum produces cells that develop into osteoblasts, which form new bone tissue. Describe one way in which hormones are involved in bone remodeling. Answers will vary.

Sample answer: Growth hormone regulates the rate at which osteoblasts create new bone during bone remodeling. Maintaining mineral homeostasis is a very important function of the skeleton, because just the right levels of calcium and other minerals are needed in the blood for normal functioning of the body.

When mineral levels in the blood are too high, bones absorb some of the minerals and store them as mineral salts, which is why bones are so hard. When blood levels of minerals are too low, bones release some of the minerals back into the blood, thus restoring homeostasis. The skeletal system consists of all the bones of the body. How important are your bones?

The Skeleton The human skeleton is an internal framework that, in adults, consists of bones , most of which are shown in Figure below. In addition to bones, the skeleton also consists of cartilage and ligaments: Cartilage is a type of dense connective tissue, made of tough protein fibers, that provides a smooth surface for the movement of bones at joints.