Blood Disorders: Major Types

Instructor: Julie Zundel

Julie has taught high school Zoology, Biology, Physical Science and Chem Tech. She has a Bachelor of Science in Biology and a Master of Education.

Normally, you don't think too much about your blood, right? This lesson will change all of that and will focus on some of the blood disorders people suffer from.

Composition of Blood

It makes up eight percent of your body weight, it contains gold, people often donate it, you can't survive without it, and your body holds ten pints of it. So, what is 'it'? Your blood! As you read this lesson, blood is coursing through 100,000 miles of blood vessels in your body!

The whole process is pretty seamless, and you probably rarely even think about blood unless you have a blood disorder, or any set of problems that impacts your red blood cells, white blood cells, platelets, or plasma. Before we delve into the major disorders, let's take a moment to go over the different things you can find in your blood, starting with red blood cells, or RBCs, for short. RBCs deliver oxygen to the tissues in your body and are red, disc-shaped cells. White blood cells, or WBCs, are cells that assist your immune system, and there are several different types. Finally, platelets are involved in blood clotting.

Left to right: RBC, platelet, WBC

The RBCs, WBCs, and platelets make up the solid portion of your blood and plasma makes up the liquid portion. Plasma constitutes half of your blood and is made up of salt, protein, and water.

Blood Disorders Affecting RBCs

Let's start the blood disorder discussion with disorders that affect RBCs. The most common blood disorder is anemia, which is the result of a low number of RBCs. Without enough healthy RBCs, body tissues do not get enough oxygen, which results in symptoms such as fatigue, shortness of breath, dizziness, pale skin, and headaches. Nearly three million Americans suffer from anemia, which has a variety of risk factors from a poor diet to cancer to kidney disease.

Another disorder affecting RBCs is sickle-cell anemia, which is a genetic disorder resulting in RBCs that 'sickle.' People with sickle-cell anemia produce atypical hemoglobin, which is the protein on the RBCs responsible for carrying oxygen. This atypical hemoglobin makes the RBCs rigid and C-shaped or sickled, hence the name 'sickle-cell anemia.' These abnormally-shaped RBCs cause problems such as preventing the flow of blood to organs, strokes, pain, infections, and organ damage.

Sickle-cell anemia overview
Sickle Cell

You've probably heard that there are different blood types, right? Yep, there's A, B, O, and AB. But you may not have heard of the Rh factor, which leads us into our third blood disorder. Rh factor refers to the presence or absence of a specific protein on your RBCs. If you have the protein, you are Rh-positive, and if you don't, you are Rh-negative.

Problems arise when a pregnant woman is Rh-negative and the fetus is Rh-positive. When the mother's blood comes into contact with the blood of the fetus, the mother's immune system does not recognize the Rh-positive protein, so it will produce antibodies that attack the baby's RBCs. Although this typically doesn't occur with the first pregnancy, it will affect later pregnancies and, if left untreated, the attack on the baby's RBCs can result in brain damage, anemia, heart failure, and even death.

You may be wondering how it got the name Rh, right? Well, 'Rh' stands for 'rhesus' because it was originally discovered in the blood of rhesus monkeys.

Blood Disorders Affecting WBCs and Platelets

Let's take a look at a couple of disorders that can affect the WBCs and platelets, starting with those affecting WBCs. Lymphoma is a type of blood cancer that begins in the lymph system, hence the name 'lymph'oma. WBCs become cancerous and then spread throughout the body.

Another type of cancer that affects WBCs is called leukemia, which occurs when WBCs become cancerous and multiply within the bone marrow, or inside of the bones. Leukemia translates into 'white blood,' which makes sense since it is a cancer that affects the WBCs.

Remember, platelets are involved in blood clotting, so platelet disorders often result in clotting issues. For example, thrombocytopenia, or having a low platelet count, can result in internal bleeding. I know 'thrombocytopenia' is another scary-sounding vocabulary word, but it's not so bad once you know it translates into thrombocyte (which is another name for a platelet) deficiency. That makes sense, right?

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