Erythrocytes (Red Blood Cells)

Erythrocytes (Red Blood Cells)

Blood Lab

The blood, heart, and blood vessels constitute the cardiovascular system. Lymph, lymphatics, and lymphoid tissue compose the lymphatic system. You will begin your study of the cardiovascular and lymphatic systems by first examining the composition and importance of blood.

BLOOD

Microscopically, blood is composed of two portions: plasma, which is a liquid that contains dissolved substances, and formed elements, which are cells and cell-like bodes suspended in the plasma. In clinical practice, the most common classification of the formed elements of the blood is the following:

Erythrocytes (red blood cells)

Leukocytes (white blood cells)

Granular leukocytes (granulocytes)

  1. Neutrophils
  2. Eosinophils
  3. Basophils

Agranular leukocytes (agranulocytes)

  1. Lymphocytes
  2. Monocytes

Thrombocytes (platelets)

The origin and subsequent development of these formed elements can be seen in your text. The shapes of the nuclei, staining, characteristics, and color of cytoplasmic granules are all useful in differentiation and identification of the various white blood cells. Because red cells are biconcave discs without nuclei, they can be identified easily. Blood cells are formed by a process called hematopoiesis, and the process by which etythrocytes are formed is called erythropoiesis. The immature cells that are eventually capable of developing into mature blood cells are called hemocytoblasts. Mature blood cells are constantly being replaced, so special cells called reticuloendothelial cells have the responsibility of clearing away dead, disintegrated cell bodies so that small blood vessels are not clogged.

  1. ERYTHROCYTES

Erythrocytes (red blood cells or RBC’s) are biconcave in appearance, have no nucleus, and can neither reproduce nor carry on extensive metabolic activities. The interior of the cell contains a red pigment called hemoglobin, which is responsible for red color of blood. Erythrocytes function to combine with oxygen and carbon dioxide and transport them through the blood vessels. A red blood cell becomes nonfunctional in about 120 days. A healthy male has about 5.4 million red blood cells per cubic millimeter of blood, and a healthy female, about 4.8 million. Erythropoiesis and red cell destruction normally proceed at the same pace. A diagnostic test that informs the physician about the rate of erythropoiesis is the reticulocyte count. The immature red blood cells called reticulocytes must appear in the blood in a cetain concentration. An abnormally low or high concentration of reticulocytes indicates a pathology.

  1. LEUKOCYTES

Leukocytes (white blood cells or WBC’s) are different from red blood cells in that they have nuclei and do not contain hemoglobin. They are less numerous than red blood cells, averaging from 5000 to 9000 cells per cubic millimeter of blood. The ratio, therefore, of blood cells to white blood cells is about 700:1.

As your text show, leukocytes can be visibly differentiated by their appearance. They are divided into two major groups, granular leukocytes and agranular leukocytes. Granular leukocytes, which are formed from red bone marrow, have granules in the cytoplasm and possess lobed nuclei. The three types of granular leukocytes are neutrophils, eosinophils, and basophils. Agranular leukocytes, which are formed fro lymphoid and meloid tissue, do not possess cytoplasmic granules and usually have spherical nuclei. The two types of agranular leukocytes are lymphocytes and monocytes.

Leukocytes as a group function in phagocytosis, producing antibodies, and combating allergies. The life span of a leukocyte is very short. In health it will live up to a few months, and during infection only a few hours.

  1. THROMBOCYTES

Thrombocytes, or platelets, are formed from fragments of the cytoplasm of megakaryocytes. The fragments become enclosed in pieces of cell membrane from the megakaryocytes and develop into platelets. Platelets are very small, disc-shaped cells without nuclei. Between 250,000 and 400,000 of them are found in each cubic millimeter of blood. They function to prevent fluid loss by starting a chain of reactions that results in blood clotting. They have a short life span, probably only one week, because they are expended in clotting and are just too simple to carry on extensive metabolic activity.

4.PLASMA

When the cellular elements are removed from blood, a straw-colored liquid called plasma is left. It consists of about 92% water and about 8% solutes. Among the solutes are proteins (albumins, globulins and fibrinogen), nonprotein nitrogen (NPN) substances *urea, uric acid, and creatine), floods (amino acids, glucose, fatty acids, and glycerol), regulatory substances (enzymes and hormones), respiratory gases (oxygen and carbon dioxide), and electrolytes (Na+, K+, Ca2+, Mg2+, Cl-, HCO3, SO42-, PO42-). The term serum refers to plasma minus its clotting elements.

Examine prepared slides of blood cells using the oil immersion objective. With the aid of your textbook and powerpoint slides, identify red blood cells, neutrophils, basophils, eosinophils, lymphocytes, monocytes, and thrombocytes.

Let’s Play Doctor

  1. In the lab:

Each lab table will need one box of “Histopathology of Disease Set” (Note: the slides are in order according to the list in the lid of the box. Please be sure the slides are still in order when you finish!)

View each of the following slides and determine what the symptoms, in the blood, for that disease are: (Hint: compare these slides with a normal blood smear)

  1. Iron deficiency anemiaC. Infectious Mononucleosis

B. Sickle-cell anemiaD. Acute Granulocytic Leukemia

On your paper, describe the microscope blood characteristics of each disease listed. Also sketch representative cells for each one.

  1. In the clinic:

See if you can diagnose the following conditions as they are presented by the patients.

  1. A patient on dialysis has a low RBC count. What hormone, secreted by the kidney, can be assumed to be deficient? ______
  1. A bone marrow biopsy of Mr. Bonglonga, a man on a long-term drug therapy, shows an abnormally high percentage of non-hemopoietic connective tissue instead of stem cells.
  2. What condition does this indicate? ______
  3. If the symptoms are critical, what short-term and long-term treatments are indicated? ______

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  1. Will infusion of whole blood or packed red blood cells be more likely? ______

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  1. A woman comes to the clinic complaining of fatigue, shortness of breath, and chills. Blood tests show anemia and a bleeding ulcer is diagnosed. What type of anemia is this? ______
  2. A patient is diagnosed with bone marrow cancer and has a hematocrit of 70%. What is this condition called? ______
  3. The very concerned parents of a young boy called Teddy bring him to the clinic because he has chronic fatigue, bleeding, fever, and weight loss. A blood test reveals abnormally high numbers of lymphoblasts, anemia, and thrombocytopenia. What is the diagnosis? ______
  4. What vitamin must be supplemented in cases of steatorrhea (inability to absorb fat) to avoid clotting problems?
  5. After multiple transfusions, a weak transfusion reaction occurs. Is this likely to be caused by the ABO antigens or to other antigens? What should be done to avoid this type of reaction? ______

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  1. Mrs. Carlyle is pregnant for the first time. Her blood type is Rh negative, her husband is Rh positive, and their first child is determined to be Rh positive. Ordinarily, the first such pregnancy causes no major problems, but baby Carlyle is born blue and cyanotic.
  2. What is this condition, a result of Rh incompatibility, called? ______
  3. Why is the baby cyanotic? ______
  4. Since this is Mrs. Carlyle’s first baby, how can you account for the baby’s problem? ______
  5. Assume that baby Carlyle was born pink and healthy. What measures should be taken to prevent the previously described situation from happening in the second pregnancy with an Rh positive baby? ______
  6. Mrs. Carlyle’s sister has two miscarriages before seeking medical help with her third pregnancy. Blood typing shows that she, like her sister, is Rh negative; her husband is Rh positive. What course of treatment will be followed? ______

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  1. The Jones family let their dog Rooter lick their faces and kissed it on the mouth, even after it explored the neighborhood dump and trash cans. Later the same day, the veterinarian diagnosed Rooter as having pinworms. Three weeks later, blood test ordered for routine physicals for camp indicated that both the family’s daughters had blood eosinophil levels of over 3000 per cc. Might there be a connection between these events? Explain. ______

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  1. An elderly man has been receiving weekly injections of vitamin B12, ever since nearly all of his stomach was removed (he had stomach cancer) 6 months previously.

a. Why is he receiving the vitamin injections? ______

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b. Why can’t the vitamin be delivered in tablet form? ______

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c. What would be the result if he refuses the B12 injections?______

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