The Blood/Circulatory System
Anatomy & Physiology I
March 18, 2013
The blood system is part of the circulatory system. I am going to be focusing on the blood and the diseases which affect the blood. The blood, heart and blood vessels form the cardiovascular system which links the body’s internal and external environments together, by transporting substances between the two. Blood is a type of connective tissue that carries nutrients, oxygen and wastes through the body. Blood cells are formed in the bone marrow. It is composed of red blood cells, white blood cells and platelets, each of which have a specific function. These three components are what we call the formed elements of blood. The remaining portion is plasma, which is a mixture of water, amino acids, proteins carbohydrates, lipids electrolytes and wastes. Plasma represents approximately 55% of blood. There are 10 liters of blood in the human body. Red blood cells account for 45% of blood composition. The normal red blood cell count is 4.2-6 million cells per microliter of blood. The functions of red blood cells are to carry oxygen from the lungs to the tissues throughout your body. Another job that they have is getting the waste, carbon dioxide from your tissues to your lungs, where you can get rid of it from your body by breathing it out. White blood cells or leukocytes account for 1% of blood by volume. A normal white blood cell count is 4,000- 10,000 cmm. The different types of white blood cells are; neutrophils, eosinophils, basophils, monocytes and leukocytes. The function of the white blood cell is to fight off infection of the body. Eosinophils control inflammation and allergic reactions, basophils work to inhibit clotting by releasing heparin. Platelets are formed in the bone marrow, their function is to clot blood, and this helps to control blood loss. The normal platelet count is 130,000- 360,000 cmm. Blood works in conjunction with the heart and lungs to provide the body with oxygen...
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