Content Summary:

Hematology is defined as the science concerning blood and blood forming tissues. The transportation of blood throughout the body is accomplished within the circulatory system. It has three main functions:
  • Transportation of all substances needed for cellular metabolism
    • Respiratory through transport of oxygen to the cells
    • Nutritive through transport of the absorbed products of digestion through the liver to the body cells
    • Excretory through transport of metabolic wastes to the kidneys
  • Regulation of hormones and temperature
  • Protection against blood loss due to injury or pathogens
    • Clotting of blood because of damage to a vessel
    • Immune through production of leukocytes

Summary #1
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The circulatory system has two subdivisions:
  • The cardiovascular system
    • Heart and blood vessels
  • The lymphatic system
    • Lymphatic vessels and lymphoid tissue within the spleen, thymus, tonsils and lymph nodes
Both systems are intertwined as the cardiovascular system forces some of blood plasma through the capillary walls into surrounding tissues. This fluid is called interstitial fluid and can either return directly back to the capillaries or enter into lymphatic vessels located in connective tissue which is later returned to the venous blood at specific sites.
Lymphatic_System.jpg

Summary #2

The blood is comprised of about 55% blood plasma, the fluid portion, and 45% formed elements, the cellular portion. Plasma consists of water and dissolves solutes with the major solute being Na+. Other solutes include various ions and organic molecules such as metabolites, hormones, enzymes, antibodies and other proteins such as albumins, globulins and fibrinogen. Formed elements include erythrocytes (RBC), leukocytes (WBC), and plalelets (thrombocytes). The WBC and platelets can also be referred to the buffy coat when examining a test tube of centrifuged whole blood.


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Summary #3
Leukocytes (White blood cells-WBC) function as the disease fighting blood cells and also promote inflammation when necessary. They contain a nucleus and mitochondria while the RBC do not. WBC move by amoeboid action and because of this, can enter capillary walls to find and fight infection. Leukocytes are either granular or agranular. Granular WBC are eosinophils, which stain pink, basophils which stain blue, and neutrohils which stain lavender. Neutrophils are the most abundant granular WBC. Agranular leukocytes are lymphocytes and monocytes. Lymphocytes are the second most numerous WBC.

leukocytes.jpg

Application:
This section of Physiology was very interesting to me because of the functions of the blood and also how blood is typed. The types of formed elements as well as their functions prove that our bodies are amazing creations. For instance, each cubic millimeter of blood within me contains approximately 4.3 million to 5.2 million RBC, each having a life span of only 120 days and just one RBC contains approximately 280 million hemoglobin molecules. RBC's transport oxygen and carbon dioxide throughout our bodies. Leukocytes numbers are quite a bit smaller yet they have the function of protecting detoxification and producing antibodies. Platelets are the smallest and are very important for blood clotting. I will not look at my blood in the same way again!
I found blood typing to be interesting. I had always wondered how each person's blood type was decided and now know our parent's role in that process. This has been my most favorite chapter so far.

Essential Question:

The ABO +/- blood typing system is shown in the chart below. This chart was found at the following site:

http://nobelprize.org/educational/medicine/landsteiner/readmore.html











Blood Group
Antigens
Antibodies
Can give blood to
Can receive blood from
AB Rh+
A, B and Rh
None
AB Rh+
AB Rh+
AB Rh -
A Rh+
A Rh -
B Rh+
B Rh -
0 Rh+
0 Rh -
AB Rh -
A and B
None
(Can develop Rh antibodies)
AB Rh -
AB Rh+
AB Rh -
A Rh -
B Rh -
0 Rh -
A Rh+
A and Rh
B
A Rh+
AB Rh+
A Rh+
A Rh -
0 Rh+
0 Rh -
A Rh -
A
B
(Can develop Rh antibodies)
A Rh -
A Rh+
AB Rh -
AB Rh+
A Rh -
0 Rh -
B Rh+
B and Rh
A
B Rh+
AB Rh+
B Rh+
B Rh -
0 Rh+
0 Rh-
B Rh -
B
A
(Can develop Rh antibodies)
B Rh-
B Rh+
AB Rh-
AB Rh+
B Rh -
0 Rh -
0 Rh+
Rh
A and B
0 Rh+
A Rh+
B Rh+
AB Rh+
0 Rh+
0 Rh -
0 Rh -
None
A and B (Can develop Rh antibodies)
AB Rh+
AB Rh -
A Rh+
A Rh -
B Rh+
B Rh -
0 Rh+
0 Rh -
0 Rh -

In order for a transfusion to be given correctly, the blood serum from the donor must be matched with the blood serum of the recipient. If the antigens and antibodies are compatible, then the transfusion can occur. If the antigens and antibodies are incompatible, then the transfusion can not occur. If the recipient was inadvertently given incompatible antigens and antibodies, then agglutination would occur. Agglutination is the clumping of RBC and can cause blockage of small blood vessels which would cause hemolysis. Hemolysis is the rupture of RBC. Hemolysis could damage the recipient's kidneys and other organs.

Type O blood is considered the universal donor because it lacks A and B antigens and the recipient's antibodies would not cause agglutination with the donor RBC.

Type AB blood is considered the universal recipient because it lacks A and B antibodies and cannot agglutinate with any donor RBC.

References : http://nobelprize.org/educational/medicine/landsteiner/readmore.html, Human Physiology by Stuart Ira Fox, Anatomy and Physiology by Stanley E Gunstream

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