Skeletal System

Fun Facts• A giraffe has the same # of bones in the neck as

humans do• Bones are 14% of your body weight• Bone is 5x as strong as steel• Most women and girls have smaller and lighter

skeletons than men and boys• The female pelvis is wider than males• Male’s growth plates harden at 18-21 years of

age• Female’s growth plates harden at 16-18 years of

age

How many bones does an adult body have?

206How many bones are babies born

with?

300

Why?

• As you grow older, small bones join or fuse together to make big ones.

Largest bone? Femur: thigh bone

Shortest Bone?

Stapes: located in the ear

What are the functions of the skeletal system?

Skeletal System Functions:

• Support framework of the body

• Protection of vital organs

• Aid muscular system in movement of body

• Production of blood cells

What’s in a bone?

1. Bone Marrow

2. Red blood cells

3. White blood cells

4. Platelets

Bone Marrow

• Bone marrow is the soft spongy tissue that lies within the hollow interior of long bones

• Two types of bone marrow: red and yellow

• Certain diseases of the bone marrow like leukemia, anemia, etc. require examination of the bone marrow tissue

• This is called a bone marrow biopsy

• A needle is used to withdraw samples of the marrow from within the bone

• This is often a very painful process

Red Blood Cells• Shaped like disks• Contain an iron-rich

protein called hemoglobin• Hemoglobin picks up

oxygen in the lungs• Hemoglobin releases

oxygen to tissues as blood travels throughout the body

• Contains more red blood cells than any other cells (lifespan of 4 months)

White Blood Cells• Key part in defending

against disease• Move in and out of

bloodstream to reach affected tissues

• Fight germs such as bacteria and viruses

• Produce antibodies

Platelets• Tiny, oval shaped cells• Help in clotting process• When a blood vessel

breaks, they travel to the area and “seal” off the leak

• Last approximately 9 days