Blue, Red, and Microscopic Tubes

Introduction: Welcome to the colorful part of the body. Most of our organs are hopefully a skin color, except for fats, which are yellow. If you look at your arms, legs, or if you are pale skinned enough...anywhere really, many can see their veins. Those are those blue lines running all along the body. These are a type of blood vessel we are going to take a look at. This section is going to address arteries, veins, and capillaries. After capillaries, a look at some of the exchanges happening at the capillaries is going to be discussed.

Definitions:

Arteries

Above is a picture seen in the previous section from htt://www.accessexcellence.org. The red, top vessels is an artery. The arteries job is to take blood away from the heart. The artery has a very strong, tri-layer wall to support it when blood enters under pressure (pg 87). Part of the layers is an elastic tissue that allows for expansion to "absorb the pressure" (pg 87).

Veins

Veins are the blue, bottom vessel in the above picture. Their primary job is to bring blood back to the heart. According to our book, the vein wall is thinner than that of the artery because there is less smooth muscle and less connective tissue. Yet, this seemingly disadvantage allows for greater expansion, allowing more blood to be flowing through (pg 87).

Capillaries

Capillaries are narrow microscopic tube that branch off from the arterioles. Arterioles are small arteries. Networks of capillaries (often referred to as capillary beds) are in all regions of the body. The function of the capillaries is to exchange materials with their surroundings.

Here is a picture of a capillary from http://www.jdaross.cwc.net.

Great Exchange

After briefly going over different types of blood vessels, let us get even closer to discuss some different exchanges that occur at capillaries.

At this website, http://highered.mcgraw-hill.com/sites/dl/free/0072464631/291136/Fluidexchange.swf
you will find the video that was in the web links. I found this to be very helpful. It explains fluid exchange in the capillaries.

The capillaries are involved in gas and tissue fluid exchange in regards to the circulatory system.
Another web site I thought was great at explaining capillary functions was this one:

http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/Bio%20102/Bio%20102%20lectures/Circulatory%20System/circulat.htm

Hopefully that link will take you directly to the Circulatory System page. Scroll down some and you will find capillaries and interstitial fluid information. It also includes images to help process the information.

Conclusion: That was the basics of blue veins, red arteries, and the tiny tiny capillaries that do so much. A fun fact, capillaries are so small, blood cells travel through in single file (you can find that on the previously provided website about capillaries). Next up is the heart. Every part of the circulatory, and our body to stay alive, depends on the heart.