What are the contents of our blood?

Normally, 7-8% of human body weight is from blood. In adults, this amounts to 4-5 quarts of blood. This essential fluid carries out the critical functions of transporting oxygen and nutrients to our cells and getting rid of carbon dioxide, ammonia, and other waste products. In addition, it plays a vital role in our immune system and in maintaining a relatively constant body temperature. Blood is a highly specialized tissue composed of many different kinds of components. Four of the most important ones are red cells, white cells, platelets, and plasma.

Red cells- or erythrocytes , are relatively large microscopic cells without nuclei.

White cells- or leukocytes , exist in variable numbers and types but make up a very small part of blood's volume--normally only about 1% in healthy people.

Platelets- or thrombocytes , are cell fragments without nuclei that work with blood clotting chemicals at the site of wounds.

Plasma- the relatively clear liquid water (92+%), sugar, fat, protein and salt solution which carries the red cells, white cells, platelets, and some other chemicals.

References:

http://http//anthro.palomar.edu/blood/blood_components.htm

http://sciencespot.net/Media/FrnsScience/bloodbasicscard1.pdf

Glossary:

Ammonia- a compound of nitrogen and hydrogen with the formula NH3.

What are blood vessels?

The blood vessels are the part of the circulatory system that transport blood throughout the body. There are three not major types of blood vessels: the arteries, which carry the blood away from the heart, the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the back towards the heart.The arteries and veins have the same basic structure. There are three layers, from inside to outside while the capillaries have only one thick cell. Capillaries consist of little more than a layer of endothelium and occasional connective tissue.

References:

http://http//en.wikipedia.org/wiki/Blood_vessels
http://http//www.diabetes.org/diabetesdictionary.jsp

Glossary:

Endothelium- the thin layer of cells that line the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall.

What causes heart failure?

All of us lose some blood-pumping ability in our hearts as we age, but heart failure results from the added stress of health conditions that either damage the heart or make it work too hard.
All of the lifestyle factors that increase your risk of heart attack and stroke – smoking, being overweight, eating foods high in fat and cholesterol and physical inactivity – can also contribute to heart failure. Below are some of the conditions that lead to heart failure;

• Coronary artery disease - This happens when fatty deposits and cholesterol build up in your heart's arteries. This will prevent the blood from flowing through the vessels and less blood will enter the heart. This will result in either a chest pain ( Angina ) or a heart attack. Coronary artery disease can also contribute to high blood pressure which overtime can lead to heart failure.


• Diabetes - Diabetes increases the risk for developing heart failure. diabetes tend to develop hypertension and atherosclerosis from elevated lipid levels in the blood — both of which have been linked to heart failure.


• Abnormal heart valves - Heart valve problems can result from disease, infection (endocarditis) or a defect present at birth. When the valves don't open or close completely during each heartbeat, the heart muscle has to pump harder to keep the blood moving. If the workload becomes too great, heart failure results.

References:

http://http//www.heartfailure.org/eng_site/hf_causes.asp
http://http//www.americanheart.org/presenter.jhtml?identifier=324

Glossary:
Endocarditis- an inflammation of the inner layer of the heart, the endocardium. It usually involves the heart valves (native or prosthetic valves).

Angina- chest pain due to ischemia (a lack of blood and hence oxygen supply) of the heart muscle.

Atherosclerosis- is the condition in which an artery wall thickens as the result of a build-up of fatty materials such as cholesterol.