BoneSChapter 5

Functions of the Bones

Besides body shape and form there are several important body functions:

Support: Bones, are the steel girds and reinforcement concrete of the body form. Supports organs. The legs as pillars to support the trunk and rib cage supports the thoracic wall.

Protection

Bones protect soft body organs

Fused bones of the skull provide a snug enclosure of the brain.

Vertebrae surrond the spinal cord

Rib cage helps protect the vital organs of the thorax

Movement

Skeletal muscles, attached to bones by tendons, use the bones as levels to move the body and its parts.

We can walk, swim, throw a ball, and breathe.

Imagine your bones turning to putty

What problems could you envision with this arrangement?

Storage

Fat is stored in the internal cavities of bones.

Serves as a storehouse for minerals, most importantly calcium and phosphorous.

Problems can occur with both too little and too much calcium storage.

Hormones control the movement of calcium to and from the bones and blood according the the needs of the body.

“Deposits” and “withdrawals” of calcium (and other materials) to and from bones go on almost all the time.

Blood cell formation

Blood cell formation, or hemotopiesis occurs within the marrow cavities of certain bones.

Classification of bones

Adult skeleton is composed of 206 bones.

There are two types of osseous, or bone, tissue:

Compact bone.

Spongy bone.

Compact Bone

Dense and looks smooth and homogeneous.

Spongy bone

composed of small needlelike pieces.

lots of open space.

Many Sizes and Shapes

The unique shape of each bone fulfills a particular need.

Bones are classified according to shape into four groups:

Long

Short

Flat

Irregular

Long

Typically longer than they are wide.

A shaft with heads at both ends.

Mostly compact bone.

All the bones of the limbs, except the wrist and ankle bones.

ex: Humerus

Short

Cube-shaped.

Mostly spongy bone.

Bone of the wrist and ankle.

ex: carpals

Flat

Thin, flattened and usually curved.

Two thin layers of compact bone sandwiching a layer of spongy bone.

Bones of the skull, the ribs, and strernum.

Irregular

Do not fit one of the previous categories.

Vertebrae, which makes up the spinal column.

Hip bones

Parts of the bone

Periosteum.

Compact bone.

Spongy bone.

Marrow (red- red cells producted and yellow- stored).

yellow can convert into red

Orientation part of bone

Epiphysis

Diaphysis

Articular cartilage

http://www.youtube.com/watch?v=inqWoakkiTc

Structure of a long boneGross Anatomy

Diaphysis, or shaft: makes up most of the bone’s length.

Composed of compact bone.

Covered and protected by a fibrous connective tissue membrane, called the periosteum.

Epiphyses, are the ends of the long bone.

Consists of thin layer of compact bone enclosing an area filled with spongy bone.

Articular cartilage, instead of periosteum covers its external surface.

glassy hyaline cartilage, provides a smooth, slippery surface that decreases friction at joint surfaces.

Microscopic Anatomy

Osteocytes: mature

bone cells, found

within the lacunae.

http://www.youtube.com/watch?v=IzM_-5YUVHQ&feature=player_embedded

Fractures- any break in bone

Break in bone.

Body able to repair.

Possible problem is not set by doctor.

Types of Fractures

Simple: Bone breaks cleanly but does not penetrate skin. Sometimes called a “closed” fracture.

Compound: Broken ends of the bone protrude through soft tissues and the skin. An open fracture. More serious than a simple fracture; may result in a severe bone infection, requiring massive doese of antibiotics.

Compound

Types of fractures

Comminuted: Breaks into fragments. Bone is crushed. Common in porous bones.

Depressed: Broken bone portion is pressed inward. Typical of skull fracture.

Types of Fractures

Impacted: Broken ends are wedged or forced together (blunt force- car accident). Commonly occurs when one falls with outstretched arms; also common in hip fractures.

Spiral: Result of twisting bone; rough edges (most common with sports fractures- too much torch force, and energy

Greenstick: Bone breaks incompletely, much in the way a green twig breaks. Common in children, whose bones have relatively more collagen in their matrix and more more flexible than those of adults.

Fracture Video

http://www.youtube.com/watch?v=P5HwYWShBhw&feature=relmfu

Epiphyseal line

The epiphyseal line is a remnant of the epiphyseal plate

epiphyseal plate

A flat plate of hyaline cartilage, seen in young, growing bones.

Causes: the lengthwise growth of a long bone.At the end of puberty, when hormones stop long

growth.

Skull Formation

http://www.youtube.com/watch?v=p-3PuLXp9Wg&feature=endscreen