The Skeletal SystemThe Skeletal System

In this slideshow, you will In this slideshow, you will learn about thelearn about the 5 functions5 functions of bone, and the of bone, and the 44 formsforms of of

bone in the human body.bone in the human body.

Deep in our body, Deep in our body, underneath our skin, underneath our skin,

muscles, and organs, there muscles, and organs, there are bones.are bones.

In each human body there In each human body there are are approximately 206 approximately 206

bonesbones. . The exact number varies The exact number varies

from person to person, and from person to person, and also depends on the person’s also depends on the person’s

age.age.

Each bone in a living body is an Each bone in a living body is an organ, made of a collection of organ, made of a collection of

different types of tissues. Some of different types of tissues. Some of the tissues are rigid (hard) and the tissues are rigid (hard) and

some of them are elastic (flexible), some of them are elastic (flexible), making bone both strong making bone both strong

and durable.and durable.

Bone has fascinated humans Bone has fascinated humans since the beginning of time, since the beginning of time,

probably because it is the part probably because it is the part of us that can last many, many of us that can last many, many

years years past our death.past our death.

Artist Leonardo DaVinci made these drawings in the early 1500s.

(Notice that he was left-handed and wrote in “mirror” style, backwards from right to left.)

In some European churches, there are entire chapels built of human bones, called ossuaries. These are most common in places were land was too important or scarce to use it for cemetaries. So people were buried for 1-3 years, then then their bones were dug up and added to the collection

The Skeletal System:The Skeletal System:

FunctionsFunctions

1. Support1. Support

•The skeleton is the supporting framework for the body

•All softer tissues hang off this frame

2. Protection2. Protection

• Bony “boxes” and “cages” protect delicate structures

For example: The skull protects the brain and the rib cage protects the heart and lungs.

3. Movement3. Movement

• Muscles are attached to bones. As muscles contract and shorten, they pull on bones and move them.

4. Storage4. Storage

• Bones are important in maintaining homeostasis of blood calcium.(Calcium is needed for normal nerve and muscle function)

• Bones are our calcium “bank”.

5. Hemopoiesis5. Hemopoiesis

• This word describes the process of making new blood cells (hemo = “blood”)

• Blood cells are made in the red bone marrow inside some of our bones

The Skeletal System:The Skeletal System:

FormsForms

There are four types of bones:

1. Long Bones1. Long Bones

These are longer than they are wide.

Example: The humerus (upper arm bone), or femur (thigh bone)

2. Short Bones2. Short BonesThese are little boxy bones that are sort of square.Example: The carpals, or wrist bones.

3. Flat Bones3. Flat BonesThese are plate-like bones.

Examples: The frontal bone at the front of the skull, or the scapula (shoulder blade) below.

4. Irregular Bones4. Irregular BonesThese are a very uneven shape with lots of bumps, holes, etc.Example: The vertebrae, or bones of the spine.

Did you know that the most Did you know that the most musical bone is a trom-musical bone is a trom-

bone?bone?

Did you find my joke humerus?

The End.The End.