The Cardiovascular System
Overall Blood Characteristics:
- Plasma 55%
- Formed Elements 45%
- Blood is 8% of our total body weight.
Where is blood produced?
- Red bone marrow forms all types of cells except lymphocytes .
- Lymphocytes are formed in lymphatic tissue, (lymph nodes, thymus, and spleen)
What controls blood production?
- Blood production is controlled by a hormone produced in the kidneys called erythropoietin.
- It's the fluid matrix of blood made up of 90% water, and the remaining 10% made of nutrients, like proteins, sugars, and fats, along with oxygen and salts.
- The function of plasma is to help maintain blood flow and also transport hormones and proteins that help maintain fluid balance in the body. It helps maintain homeostasis by transporting heat throughout the body.
- People are paid to donate plasma because it takes time and commitment, and in order to continue having people donate plasma they are compensated with a modest amount of money, showing the appreciation of the donor company. Once a person becomes a certified donor, they go through a process of steps including paperwork and tests and from there they lay down and begin the process where blood is drawn from their veins. Plasmapheresis is the process where the red blood cells are returned to the body leaving just the plasma to be donated.
Red Blood Cells- Erythrocytes
- Red blood cells are caved in on both sides, creating a thin center and larger edges. They also do not contain a nucleus. There are about 250,000,000 molecules per mm3.
- The main function for red blood cells is to help transport carbon dioxide from out of the cells and into the lungs to dispose of it. They also transport oxygen from the lungs into different cells. Oxygen helps maintain homeostasis because it helps metabolic activities continue which happens during cellular respiration.
- A hematocrit test measures the total volume of blood made up by the red blood cells. The test works by having a specialized tube spun down into a centrifuge where the heavier elements sink to the bottom. There is a standard of normal blood, and then the height of red blood cells in the test is compared to the height of red blood cells in normal blood. The test monitors the red blood cell percentage and can diagnose certain blood disorders.
- What is anemia?
Anemia is the term that describes a number of blood disorders where the blood is unable to carry enough oxygen to body cells. It can occur because of many factors including a too low number of red blood cells, or lack of hemoglobin.
Types of Anemia
- Hemorrhagic anemia results from a decrease in the number of red blood cells caused by hemorrhage often from an accident or bleeding ulcers. Possible treatment of this disorder is to undergo a blood transfusion to get the red blood cell count back to normal.
- Pernicious anemia results from a lack of red blood cells because of a failure of the stomach lining to produce "intrinsic factor" which allows stomach linings to produce B12. A treatment for this anemia requires injections of vitamin B12, over long periods of time, to maintain the critical red blood cell count.
- Sickle cell anemia is one of the most severe and sometimes fatal hereditary disease which is caused by an abnormal type of hemoglobin. Red blood cells contain a small amount of a type of hemoglobin which is less soluble creating crystals where blood oxygen is low creating distortion of red blood cells. If more than one gene is inherited the disease can become extremely severe. Because of the severity of the disease, the only treatment is a bone marrow transplant. The transplant can be extremely rare, dangerous and sometimes even fatal.
- Iron deficiency anemia occurs worldwide. If the iron levels in hemoglobin falls below the normal it causes a chain reaction of events including less oxygen transported to cells causing slower breakdown, creating less energy which in total decreases cellular functions. It causes the individual to be tired all of the time. A treatment for this anemia is to either take iron pills or ingest iron through natural foods to raise the level.
- Hemolytic anemia occurs when red blood cells are destroyed before their normal lifespan ends. Mild cases do not always have to be treated, but in a more severe case proper treatment, like blood transfusions.
- Polycythemia is when bone marrow produces an excess of red blood cells. A cause of this is when there is low oxygen in the air and blood causing the red blood cell build up. This can be treated by various medications but with many side effects the uses of those medications are very limited.
- After filling out various paperwork and meeting the requirements of the physical, a physician will insert a sterile needle your arm and begin to draw the blood. After the blood is drawn and your donation is complete you will need to wait 10-15 minutes to get your body back to normal, and of course refreshments will be provided. A healthy donor can donate blood every 56 days, with the blood having a shelf life of up to 42 days. The blood donated can be used to help up to 3 people, it is brought into a Red Cross laboratory, where it is separated into red blood cells, plasma, platelets and white blood cells.
White Blood Cells- Leukocytes
- White blood cells are classified by the presence of granules or absence of granules in cytoplasm. The three granular leukocytes are neutrophils, eosinophils, and basophils. The nongranular leukocytes are lymphocytes and monocytes. There are 4.8-11,000 molecules/ mm3.
- The function of white blood cells is very important, they work in the immune system and help defend against cancerous cells that form inside tissues. By fighting infections, white blood cells help maintain homeostasis by keeping the body helping.
Types of White Blood Cells:
- Granulocytic white blood cells-
- Neutrophils are the most common, with 60%, and they have a segmented nucleus. Neutrophils, which show up purple on a slide, are found in acute bacterial infections and they are highly phagocytic.
- Eosinophils are larger than neutrophils but much less common taking up only 2%. These cells, which stain red or orange, fight parasitic infections like worms.
- Basophils are the rarest, with only .004%. They contain a bilobed nucleus and stain dark blue and purple. These cells are involved in inflammation and swelling and they contain heparin.
- Lymphocytes are the second most numerous white blood cell making up 31%. They contain a large, round nucelus with very little cytoplasm. Although they are non-phagocytic they live a very long life, provide immunity and fight viruses.
- Monocytes are the largest of all white blood cells. They are distinguished by their kidney-shaped nucleus. These cells are highly phagocytic and mainly seen in chronic infections.
Conditions relating to white blood cells
- Leukopenia is the disorder where an individual has extremely low counts of white blood cells. One could take medications in order to treat this disease, but also chemotherapy may be used to stimulate the bone marrow to produce more white blood cells.
- Leukemia is the term which describes blood cancer affecting the white blood cells. When there is an excess of white blood cells the levels rise immensely and depending on how soon the symptoms show up determines the proper treatment. Induction therapy, consolidation therapy, and maintenance therapy are all used to treat all forms of leukemia. Once an individual stays five years without showing any signs of symptoms they are considered cured.
- Mononucleosis more commonly known as mono, or the kissing disease, is spread through saliva. Doctors can tell you have mono by taking a blood test and looking for a higher number of white blood cells, or abnormal looking lymphocytes. This is mainly self-treatable, with no direct treatments. Many people just use advil or rest as the disease goes away after 4-6 weeks.
- Multiple Myeloma is a rare disease of the cancer of the plasma. Many treatments such as steroids, blood transfusions, chemotherapy, and STEM cell transplantations are some of the many.
- Platelets are produced in the red bone marrow like the others, but they are little pieces that break off from megakarocytes. These cells are non-living and there are usually around 200-500,000 per mm3.
- The platelets main function is to be responsible for initiating a clot. When a clot is formed, the blood flow stops flowing out of that area which helps maintain homeostasis by not letting all of the blood out.
- Hemostasis is the stopping of blood, or clotting. There are three events that have to occur. First, a vascular spasm, next a platelet plug is formed creating a temporary seal, and finally a clotting cascade which is also called a coagulation. This process is not possible without a healthy liver.
- Hemophilia is a disorder where the blood does not clot normally due to a lack of blood clotting proteins. One may bleed much longer than a person with normal blood would. There is no cure for hemophilia but it is possible to lead a normal life with the disease. A doctor may recommend certain medications that deal with clotting, physical therapy, or fibrin sealants to name a few options.
- Coumadin or warfarin helps prevents blood clots from forming and also helps to keep existing blood clots from growing.
- Heparin prevents clotting in blood vessels before or after surgery or medical procedures. This can also help prevent disorders of the heart, blood, and lungs.
- Aspirin treats pain , fever, and inflammation. Aspirin should not be used if you have a bleeding disorder.
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