unit 4 - skeletal system

skeletal

what are the functions of the bones?

they support, protect, add movement to the body, mineral storage, and hematopoisesis

how does the bone support the body?

by contributing to shape, alignment, and position of the body

how does the bone protect the body?

through the skull, ribs: for the brain and the lungs.

how does the bone provide movement to the body?

it allows for muscles to be anchored to act as levers.

how does the bone be mineral storage?

its a reservoir for calcium, phosphorus, others..

calcium moves into or out of bones to keep blood levels steady

What is hematopoiesis?

It is blood cell formation, occurring primarily in red marrow.

Hyoid Bone

Single U shaped Bone, just above larynx

Tongue muscles attached

Only bone to articulate on its own

Part of the axial skeleton

What are the 4 types of bones?

Long bones, short bones, flat bones, and Irregular bones.

long bones?

Long axis with unique shaped articular ends

ex: femur (thigh), humerus (arm)

short bones?

Cube or box shaped

ex: wrist(carpals) or ankle(tarsals) bones

flat bones?

broad and thin with often curved surfaces.

red marrow found in some flat bone like: sternum.

Irregular bones

Come in clusters and come in various shapes and sizes

Sesamoid bones are irregular bones that are found alone, like kneecap (patella).

What is this?

Long Bones

What is this?

Short bones

What is this?

Flat bones

What is this?

Irregular bones

What are the parts of a long bone?

The diaphysis, the epiphyses, the epiphyseal plate, and the articular cartilage

Diaphysis

Main shaft portion of bone

Cylindrical and hollow

Very strong yet light

Epiphyses

• Bulbous shape at end of bones

• Site of muscle attachments

• Made of spongy, cancellous tissue filled with red marrow

Epiphyseal plate

• layer of cartilage seen in early development

• separates epiphyses fromseparates epiphyses from

Diaphysis.

• In mature bone is referred to as the metaphysis

Articular Cartilage

• Thin layer of hyaline cartilage that

covers epiphysis.

• Cushions jolts and blows

Periosteum

Dense white fibrous tissue, covers bone and joint surfaces

Periosteum fibers penetrate underlying bone

Muscle tendon fibers interlace with periosteal fibers anchoring them into place

Contains bone forming and destroying cells

Contains blood vessels that aid in born formation and repair of bone

Medulllary (marrow) cavity

• Hollow space of diaphysis

• Filled with fatty yellow marrow

Endosteum

• Thin membrane that lines medullary cavity.

Bone tissue

• made of cells, fibers, and extracellular fluid

• extracellular material predominates and is hard and calcified

• contains many collagen fibers

• Tensile strength equal to iron with 1/3 the weight

• Structure allows bone to carry out its supportive and protective function.

Bone Matrix

Inorganic Salts:

• Hydroxypatite- specialized crystals of calcium and phosphate

• Hardness of bone results from deposition of hydroxyapatite

• other minerals found in bone are magnesium, sodium, sulfate, and flouride.

Osteopororsis

• Age related disease which results on loss of bone mineral density

• Causes bone fragility and susceptibility to fractures.

• White women during the first 10 years of menopause are most susceptible.

Treatment:

• Hormone replacement therapy

• ]Non-hormonal drugs

• Calcium supplements

• Weight bearing exercise

Bone Matrix

Organic Matrix:

• Composite of collageous fibers and ground substance

• Ground substance: gel like, made of protein and polysaccharides, provides support and adhesion, aids in growth, repair and remoldeling, and adds to overall strength.

Compact bone - Haversian systems or osteons

• functional units of compact bone

• main function is to provide nutrients and remove wastes from osteocytes trapped in bone.