Virtual Pathology Lab

Data Table

Below is a captured screen shot of the Virtual Pathology exercise case for Mononucleosis

 

Journal Questions 

 

1--In what ways do normal red and white blood cells differ?

When comparing red and white blood cells, we can differentiate based on several characteristics, such as: quantity, function, composition, and origin from the stem cells.

·        QUANTITY

Looking first at the quantities found in a person having a normal blood count, the red far outnumber the white blood cells. White blood cells (WBC) together with platelets comprise just one (1) percent of a given volume of whole blood compared to a 44 percent level of red blood cells (RBC).

·        FUNCTION

Under the right conditions, RBC are the’ worker ants of the blood’ that contain millions of proteins that tirelessly transport oxygen. In fact, a single red blood cell “can carry up to 1.2 billion molecules of oxygen.” [Human Biology textbook, p. 145] To a far lesser degree, the RBC in the blood transport carbon dioxide from the tissues.

WBC are designed to fight infection and protect the body when injured. These are the warriors of the bloodstream, the samurai who defend against invaders and have a short lifespan. They sense a threat and emit chemicals that create more WBC, calling in reinforcements when needed. Sometimes the new WBC come from the storehouse of the spleen and sometimes they are generated from the bone marrow. The WBC basically scour the body and “dine” on fungi, bacteria and parasites.

There are two types of WBC: granular and agranular. Neutrophils are the largest percentage of granular WBC and are the first responders to the scene. Other granular WBC called Eosinophils are able to act like the Lilliputians in Gulliver’s Travels who swarm and secure a larger giant. In this case, rather than stake to the ground, they use enzymes to digest unwelcome parasites. They also are responsible for chemical reactions that modulate allergic reactions in the body. A third type of granulocyte is known as the Basophils, which release histamine and help to bathe injured tissue in plasma released from nearby blood vessels.  

·        COMPOSITION

WBC are larger than RBC and are translucent-primarily because they lack hemoglobin and contain nuclei; red blood cells do not have a nucleus.

·        ORIGIN FROM STEM CELLS

Mature red blood cells, also called “erythrocytes,” derive from erythroblasts created from stem cells.  The clever design that cast out the nucleus gives the mature RBC a unique dimpled shape that makes it flexible and able to squeeze into tiny blood vessels.

All of the granular leukocytes (WBC) such as neutrophils, eosinophils and basophils, originate from stem cells by way of “myeloblasts”.

There are two agranular leukocytes (WBC), with the Monocyte originating from the Monoblasts, and the Lymphocytes originating from the Lymphoblasts.  

2. Which type of white blood cell would you expect to be most common in a normal blood smear?

Neutrophils are most commonly found in a normal blood smear

 

3. A differential count of white blood cells from a patient gave the absolute number of lymphocytes as 8000 per mm3 and the total number of white blood cells as 12,000 per mm3. Calculate the percentage of lymphocytes in this sample of white blood cells. Is this a normal or abnormal percentage? Explain your answer.

A normal range of lymphocytes is the 20 to 40 percentile, so this an example of an abnormally high percentage, in the neighborhood of 67 percent.  

4. Describe the difference between a communicable disease and an inherited disease. Use examples you have studied in this exploration to support your description.

  

Essentially, the difference between a communicable disease and an inherited disease is that you can pass a communicable disease to others primarily through vectors such as parasites, viruses, or bacteria via physical contact; transmission often occurs through exposure to blood, saliva, fluid from the mucous membranes of the lungs and airways, and other body fluids. 

Inherited diseases are of course transmitted via the genetic roulette of procreation, but having a genetic variation that fits the definition of a disease is dependent on the cellular matrix unique to offspring and mutations in genetic code that persist generation to generation. 

For example, research shows that people with chronic myelogenous leukemia, which is one of those rare diseases characterized by the bone marrow factories being overrun by abnormal and inefficient white blood cells, have an abnormal chromosome as the causal factor. However, the boundary zone for leukemia origin between communicable and inherited is fuzzy; environmental exposures and even viral infections are thought to be the causal factors in some cases.

The person cannot maintain the homeostasis and intricate symphony of balances that normally keep white blood cell production in the proportion needed for good health and a strong immune system.

 

5. Why are white blood cells in a stained blood smear usually counted at low power under a microscope? Explain your answer.

White blood cells are large elements in a given blood sample so it would be like taking a close up photo of a giraffe and only seeing a spot on the neck if you use the high power. Use the low power magnification when examining a stained blood smear of white blood cells and you can see and count their numbers much like a camera with a wider lens will be able to capture not just the spot, but the entire neck of the giraffe as well as the head, body and legs.

6. Why is the presence of a larger than normal number of neutrophils indicative of an infection? Explain your answer.

Neutrophils are the first line of defense and as such, they aggressively outnumber and basically engulf a foreign body or invader such as bacteria or virus before it can spend much time or do much damage. When they mass, this is a sure sign of an infection, of the immune system working as designed to thwart what does not belong.

7.  Why would you not expect to see tissue macrophages in a blood smear? Explain your answer.

Macrophages are a type of large white blood cell that are like the trash trucks that come by to remove the red blood cells that reached their expiration date of 120 days. The liver and spleen are where old RBC get destroyed. Much like the neutrophils engulf foreign bacteria or viruses, the macrophages engulf the no longer useful RBC and digest them. It’s a process called “phagocytosis” and it’s a housekeeping duty our bodies perform at the cellular level.

Blood smears are a snapshot of what is going on in the bloodstream. Since the old red blood cells are more or less sequestered in the liver and spleen for this housekeeping, the macrophages typically won’t be visible in a blood smear.