the skeletal system. basics skeletal system – bones and connective tissue that holds them together...

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The Skeletal System

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Page 1: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

The Skeletal System

Page 2: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

Basics

• Skeletal system – bones and connective tissue that holds them together

• Human skeleton has 206 bones

• Cartilage – flexible connective tissue found between bones

http://www.msnucleus.org/classes/images/skeleton_dancing_lg_nwm.gif

Page 3: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

More Basics

• Joint – place where two bones meet

• Ligament – long flexible band of connective tissue that connects two bones at a joint

Page 4: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

“Divisions” of the Skeletal System

Appendicular• Allows body

movement

• Bones in the limbs that extend from trunk: legs, arms, feet and hands

Axial• Bones found

in head and trunk

• Includes vertebrae that protect the spinal cord

Page 5: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

Major Bone Structure• Spongy bone: less

dense & surrounded by compact bone.

• Compact bone: hard & dense with calcium rings

• Periosteum: layer of connective tissue that covers/protects the bone.

Page 6: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

Compact Bone Structure

• Made of calcium-rich rings maintained by bone cells (osteocytes).

• At the center of the rings are channels called Haversian canals, containing a small blood vessel.

Page 7: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

Functions of the Skeletal System• Provides support• Allows for movement• Protects internal organs• Storage bank for minerals

(calcium)• Location for blood cell

formation– Red bone marrow is found

in the spongy bone and produces blood cells

– Yellow marrow is mostly fat but can change back to red marrow if necessary (forms from red marrow)

Different types of cells / cell parts produced in bone marrow

Page 8: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

Bone Growth

• Bones grow from their ends.

• They grow longer, thicker & wider.

• Human embryos start out with skeletons mostly made of cartilage.

• Osteoblasts – cells that secrete collagen and calcium phosphate to cause hardening – this is called ossification.

Page 9: The Skeletal System. Basics Skeletal system – bones and connective tissue that holds them together Human skeleton has 206 bones Cartilage – flexible connective

Broken Bones

• Osteoblasts heal damaged/broken bones after growth has ended.

• Bones are strongest between 18 and 30. After that, calcium may be taken from the bones and used elsewhere in the body -so drink your milk!