The Skeletal System

DAY 11 -

Skeletal System Lecture

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Your BELLRINGER/DO NOW is next.

Multiple Choice

Which of the following is NOT a function of the skeletal system?

• Digest food

• Support body

• Movement

• Create red blood cells

Multiple Choice

The skeletal system grows and develops as you grow older.

• True

• False

The skeletal system is...

+ The inner-most organ system in your body

+ What provides support and structure to the other organs

+ One of two systems that help you move

+ Where new red blood cells are created

Without it, we'd just be a puddle of trembling flesh. Yuck.

Some Basic Facts:

Bones help store nutrients and other materials for later - like calcium!

They also control how and when your hormones are released...

Many bones surround and protect your internal organs, like:

+ Cranium protects brain

+ Vertebrae protect spinal cord

+ Ribs protect heart/lungs/more

Multiple Choice

Which of these bones protects the brain?

• Scapula

• Cranium

• Mandible

• Clavicle

More Basic Facts!

Adults have about 206 bones, BUT

- children have more - 270 bones!

As you grow older, long bones "fuse" together (like with glue)!

Bones continue to adapt/change as you grow older - healing small and big fractures with calcium.

Multiple Choice

The reason adults have less bones than children is because they lose their teeth as they get older.

• True

• False

Did you know bones have layers?

Oh, it gets weirder than that. Look!

As you can see bones are ALIVE! They have blood vessels inside them as well as bone marrow. They're "spongy" inside!

Bones have layers!

The hard, calcium layer we think about in bones is the compact bone.

It's not as strong as the spongy bone though! "Holes" help carry weight - up to 1 ton at the knees!

Bone marrow is where new blood cells are born and "fills" the bone.

Blood vessels feed the bone cells!

Bone layers at work:

Say you jump down and land on your feet again. When you come down, your leg bones could feel a pressure of up to 1 ton of weight.

Your weight + the force of gravity!

Compact bone transfer the force to the spongy bone and they "break it down" until it's easy to handle.

Multiple Choice

Which of these layers of the bone help you "absorb shocks" without breaking?

• Compact bone

• Blood vessels

• Spongy bone

• Cartilage

Without spongy bone to "cancel" the force of falling/jumping/moving...

The compact bone would break and fracture in horrible ways!

Behold, the

wonders of cartilage and ligaments!

Cartilage is a smooth, low-friction surface between bones. This helps them move against each other without wearing out!

Ligaments are stretchy but STRONG and help connect bones together!

Without the ligaments to hold your bones together, they would go everywhere! We'd be unable to move.