main functions of the skeletal system

8/6/2019 Main Functions of the Skeletal System

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Main functions of the Skeletal System:

A skeleton provides "cages" to protect the delicate organs. For example: the ribcage helps

protect the lungs, heart, etc. Moreover, it gives muscles "sides" or edges to attach to

(through tendons of muscle and the tough periosteum of bone). It also maintains balance,

and supports the body's shape. But all these functions are perhaps secondary to theprimary function of locomotion. The bones allow the muscles of the body to move the limbs.

Hemopoiesis is also an important function of bones. This is the process of red blood cell formation and

is carried out by stem cells in active red bone marrow. Much of red bone marrow becomes inactive when

you reach adulthood and turns into fatty tissue called yellow bone marrow. Sites in adults for active red

bone marrow are: flat bones of the skull, vertebrae, ribs, sternum, ossa coxae, and the proximal ends of

the humerus and femur.

Bones come in different sizes; and shapes,the longest bone is the femur, and the shortest,

the stapes. The outer layer of bones are called compact bones, and the middle, called

spongy or cancellous bone, which are hollow and contain bone marrow. Joints of bones areheld together by ligaments, which are fine fibers attaching to each bone at joints. In order

for bones to not scrape against each other, slippery cartilage and synovial fluid are covered

atop the bones.


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Connective tissue is a fibrous tissue.[1]

It is one of the four traditional classes of tissues (the others

being epithelial, muscle, and nervous tissue). Connective Tissue (CT) is found throughout the body. It has

3 main components; cells, fibers, and extracellular matrix. Connective tissue makes up a variety of

physical structures including, tendons, blood, cartilage, bone, adipose tissue, and lymphatic tissue. CT is

classified into three subtypes; Embryonic CT, Proper CT, and Special CT. The Proper CT subtype include

dense regular CT, dense irregular CT, and loose CT. The Special CT subtype

includes Cartilage, Bone,Adipose Tissue,Blood, Hematopoietic Tissue (tissue that makes blood cells)

and Lymphatic Tissue.

Bone marrow is the flexible tissue found in the interior ofbones. In humans, bone marrow in large bones

produces new blood cells. Bone marrow is also a vital element of thelymphatic system, as it

produces lymphocytes and acts to prevent the backflow oflymph.

Marrow types

There are two types of bone marrow:red marrow (consisting mainly ofhematopoietic tissue) and yellow

marrow (consisting mainly offat cells). Red blood cells, platelets and most white blood cells arise in red

marrow. Both types of bone marrow contain numerous blood vessels and capillaries.

At birth, all bone marrow is red. With age, more and more of i t is converted to the yellow type; only around

half of adult bone marrow is red. Red marrow is found mainly in theflat bones, such as the hip

bone, breast bone, cranium, ribs, vertebrae andshoulder blades, and in the cancellous ("spongy") material

at the epiphyseal ends oflong bones such as the femurandhumerus. Yellow marrow is found in

the medullary cavity, the hollow interior of the middle portion of long bones.

In cases of severe blood loss, the body can convert yellow marrow back to red marrow to increase blood

cell production.

Cancellous bone, synonymous with trabecular bone orspongy bone, is one of two types ofosseous

tissue that form bones. Compared tocompact bone, which is the other type of osseous tissue, it has a

highersurface area but is less dense, softer, weaker, and less stiff. It typically occurs at the ends of long

bones, proximal to joints and within the interior of vertebrae. Cancellous bone is highlyvascularand

frequently contains red bone marrow where hematopoiesis, the production of blood cells, occurs. The

primary anatomical and functional unit of cancellous bone is thetrabecula.


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main functions of the skeletal system

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