Skeletal System

The Skeletal System

• What is the Skeletal System?– A system of

mineralized hard and soft tissues that span the inside of the body.

– “Frame work” of your body

The Skeletal System

• Three things that make up the skeletal system:– Bones: hard mineral tissue

(calcium)– Cartilage: tough, flexible

connective tissue– Joints: Places where two

or more bones meet

The Skeletal System

• Purpose of the Skeletal System:– Protect internal organs and soft

tissues.– Support of your body organs against

the pull of gravity– Something for muscles to hold onto

so you can move– Storage for necessary minerals

(calcium) & fats – Produces Blood for the body

The Skeletal System

• Major Divisions in the skeletal system:– Axial: Bones along the

center axis (medial) of the body.• Skull, Vertebral column,

rib cage

The Skeletal System

• Major Divisions in the skeletal system:– Appendicular: consists of

appendages that attach to the axial skeleton.• Pectoral girdle, pelvic

girdle, limbs

Axial Appendicular

The Skeletal System

• Bone Formation:– Start out as cartilage– Eventually form bone• Baby: 350 bones• Adult: 206 Bones

– Specialized cells continuously break down and reform bone

• Compact bone: dense and looks smooth and homogeneous

• Spongy bone:composed of

small needlelike pieces of bone and lots of open spaces

The Skeletal System

The Skeletal System

• Types of Bones:– Flat: • Thin, flattened and

usually curved• Two thin layers of

compact bones sandwiching a layer of spongy bone between them• E.g. Skull, ribs and the

sternum

The Skeletal System

• Types of Bones:– Long: • Longer than they are wide• Contain mostly compact

bone• Like steel beams, these

weight bearing bones provide structural support• All the bones of the limbs,

except the wrist and ankle bones, are long bones

The Skeletal System

• Types of Bones:– Short: • Approx. as wide as they

are long• Contain mostly sponge

bone• Look like blocks and allow

wider range of movement than larger bones• E.g Carpals of the wrist

The Skeletal System

• Types of Bones:– Irregular: • Bones with complex

shapes that are not easily fit into other categories• Usually have projections

that muscles, tendons, and ligaments attach to• E.g. Vertebral column,

facial bones