Bone Structure

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Bone Structure Objectives

Identify and explain the roles of the cells and blood vessels found within an osteon.
Describe the research on bone density related to aging and exercise.

In the previous section, you were introduced to basic bone structure and functions. In this section we are starting with a closer look at the bone tissues and cells.

Bone is continually remodeling based on changes in our activities. This image is of osteoblasts (purple) on the outer layer of bone (pink). These cells can extract calcium and other minerals from the blood and deposit it in a bony matrix.

Osteoblasts build bone, and osteoclasts do the opposite. Why is this balance important?

Let’s do a bit of microscope work. In the last module we were set up in a closet; this week we have a new space for microscopy.

You can select the closed captioning “cc” option if you would like to see the text.

In this figure,

What runs through the center of the osteon (labeled #1)?

What are the living cells cemented within the bone?

In the microscopy video, the first image is of a disc between vertebrae. Discs have a different type of connective tissue than bone; cartilage. Cartilage is found in many firm but flexible structures like your ears or padding between bones. The cells (chondrocytes) have a unique appearance, like there is empty space around them. We’ll look at them in closer detail when we cover the respiratory system because cartilage also lines the outside of the trachea (windpipe).

Now that you have the basics of bone structure, let’s take a closer look at research on maintaining bone health.

The next section introduces bone disorders, including fractures and inflammation.

Check your knowledge. Can you:

identify and explain the roles of the cells and blood vessels found within an osteon?
describe the research on bone density related to aging and exercise?