Blood Vessels:

Blood Vessels- Are intricate networks of tubes that transport blood throughout the entire body. There are four types of blood vessels arteries, veins, capillaries, and sinusoids.
Arteries- Are elastic vessels that transport blood away from the heart. The largest artery of the body is the aorta. The aorta originates from the heart and branches out into smaller arteries. The smallest arteries are called arterioles which branch into capillaries.
Arteries are made up of three layers- Tunica Adventiti, Tunica Media, and Tunica Intima.
Tunica Adventiti- The tunica adventitia is the strong outer covering of arteries and veins. It is composed of connective tissue as well as collagen and elastic fibers. These fibers allow the arteries and veins to stretch to prevent over expansion due to the pressure that is exerted on the walls by blood flow.
Tunica Media- Is the middle layer of the walls of arteries and veins. It is composed of smooth muscle and elastic fibers.
Tunica Intima- Is the inner layer of arteries and veins. In arteries this layer is composed of an elastic membrane lining and smooth endothelium that is covered by elastic tissues. Veins do not contain the elastic membrane lining that is found in arteries.
Veins- Are elastic vessels that transport blood to the
heart. The smallest veins in the body are called venules. They receive blood from the arteries via the arterioles and capillaries. The venules branch into larger veins which eventually carry the blood to the largest veins in the body, the vena cava.
Capillaries- Are extremely small vessels located within the tissues of the body that transport blood from the arteries to the veins. Capillary walls are thin and are composed of endothelium (a single layer of overlapping flat cells). Oxygen, carbon dioxide, nutrients and wastes are exchanged through the thin walls of the capillaries.
Sinusoid-The liver, spleen and bone marrow contain vessel structures called sinusoids instead of capillaries. Similar to capillaries sinusoids are composed of endothelium. The individual endothelial cells however do not overlap as in capillaries and are spread out.

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Blood Structure:

There are four main components of blood, which are plasma, red blood cells, white blood cells, and platelets. The major function of blood is to transport all the vital substances necessary to live. All blood cells originate from a “stem cell” which is found in bone marrow (blood cell factory). Blood is about 7% of your body weight.
Blood Structure Notes

Plasma- is about 50% of your blood. It contains different materials like proteins, glucose, salts, vitamins, hormones, and antibodies. Plasma keeps the blood flowing.
Red Blood Cells- “erythrocytes” which has two main functions. First is to carry oxygen to all the tissues coming from the heart/lungs. After it has used the oxygen the red blood cells carry carbon dioxide back to the heart.

Video: Red Blood Cells

White Blood Cells- “leukocytes” They defend the body against bacteria. Each blood cells fight the body enemies differently. Some white blood cells produce antibodies, detoxify foreign substances, and digest bacteria.

Platelets- these are small fragments clump together and stick to inner surface of blood vessels to plug up leaks. The platelets release a substance for clotting of blood. The platelets cause the injured site to shrink and seal off.
Video: Platelets

Blood Analysis:

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Blood carries out many important functions in the body. The examination of blood is valuble for the early detection of serious health conditions. Doctors examine blood and mostly rely on blood tests to diagnose and monitor diseases. After blood is drawn, doctors can start analyzing. Blood tests can show both chemical and physical properties of blood. Blood analysis includes the determination of the number of red blood cells, the classification of blood, the study of the structure of blood proteins, the determination of the activity of enzymes, and the study of blood chemistry. Dark Field Microscopy is one way to analyze blood. To analyze the blood, blood must be drawn from your finger and that drop of blood is used under a microscope called a Dark Field Microscope. ( This type of blood analyzing allows us to observe multiple vitamin and mineral dificiencies, toxicity, tendencies towards allergic reactions, excess fat circulation, liver weakness, and arteriosclerosis.
The second video on this website shows how doctors can test ratios and types of white blood cells to find abnormalities that cause health problems such as allergic reactions.
Here is an example of a complete blood analysis

Without blood analysis, doctors wouldnt be able to determine if their patients had certain heath problems or diseases. This would mean there wouldnt be cures for certian diseases and life today would be very different.