How Blood Works and the Difference Between Blood Types
There are several different types of blood. Contained within them are several different types of cells, and countless molecules that give our bodies the needed nutrients to work effectively. The two main types of cells within the blood are red and white blood cells. Red blood cells make up nearly 45% of your blood volume. White blood cells make up less than 1%. What is left over is known as blood plasma. This makes up approximately 55% of your blood volume.
Before we get into what exactly all of these parts do, let’s take a quick look at where all those things come from. For simplicities sake I’ll just say that almost everything that goes into blood gets there from your digestive tract, your lungs, or your bone marrow.
You can think of your digestive system as a system that is separate from the rest of your body, just contained within it. It starts at your mouth and ends at your anus. Everything that gets put in your mouth must be broken down by this system and then passed through it to get into your blood stream. Most nutrients in your blood get there this way. The statement, “you are what you eat” is actually pretty amazingly accurate!
Another way things can get into your blood stream is through the small capillary beds within your lungs. Most of the time it’s just the oxygen we need and carbon dioxide that we want to get rid of that’s transferred to and from blood this way. Inhale something like pot, however, and see if this isn’t a very quick way to get almost anything circulating around your body, just don’t forget the Cheetos!
Lastly, red blood cells and most white blood cells are predominantly created within the bone marrow of large bones. Red blood cell production is controlled by a hormone called erythropoietin (EPO). Yes, the same EPO that Lance Armstrong appears to have loved so much. Viva the king of the cheaters! White blood cell presence and production is controlled by complex mechanisms within the immune system.
There are 8 main types of blood separated into 4 groups. The groups are A, B, AB, and O. They are grouped together by the presence or absence of what is known as an antigen. Antigens are substances within the blood that cause our immune systems to create antibodies. These antibodies then kill anything the immune system thinks is a threat. The specific antigens that create the different blood types are found on the surface of red blood cells and are known as type A and type B. They’re further separated by the presence of another type of antigen known as rH factor. If you have this rH antigen present, you’re considered positive, if not, you’re considered negative. Someone that has type A antigens and rH factor is considered to have type A+ blood. If you have both types of antigens and no rH factor, you have type AB- blood. If you have no A or B antigens then you are type O blood.
All of this matters because of those antibodies your immune system creates. Someone with type A blood will have antibodies for type B, and someone with type B will have antibodies for type A. Type O has antibodies for both A and B. If you were to give type B blood to someone who was type A, their antibodies would attack the type A red blood cells causing very unwanted side effects, including possible death!
Now that we know what the different types of blood are, let’s look at the things within it.
Red blood cells are what carries oxygen throughout your body and helps carry carbon dioxide away from your cells. They’re made from a protein known as hemoglobin. It’s this hemoglobin that makes red blood cells red, and it’s the large number of these that give your blood its red appearance. (And note, contrary to popular belief, deoxygenated blood does not turn blue.)
Hemoglobin contains large amounts of iron. It’s this iron that oxygen binds too. Cells that are working appropriately create hydrogen atoms that cause a lower than normal pH level within it. When hemoglobin is delivered to the cells that need oxygen, a low pH will cause the iron to release the oxygen molecule and your cell now has all the oxygen it needs to metabolize appropriately. Red blood cells also help carry about 14% of the produced carbon dioxide and hydrogen atoms away from the cells and back to the lungs. The other 86% is transported in the blood as bicarbonate (HCO3-). The specifics of why and how this works is a chemistry lecture waaaayyy too long for this article, so you will just have to take my word for it (or check out the references below for more detail on it).
The other specific type of cell within your blood is white blood cells (WBC). Known as leukocytes, these cells are part of our immune system and help protect the body from infections. There are 6 main types of white blood cells numbering approximately 4-10 thousand per microliter of blood. If that number is increased, then you probably have an infection that your body is trying to fight.
The 6 main types are: Neutrophils, Eosinophils, Basophils, Bands, Monocytes, and Lymphocytes. Each type plays a different role in the kind of infection your body is trying to fight. For example, Neutrophils kill bacteria by ingesting them (called phagocytosis). If you have a bacterial infection, the percentage of neutrophils within your blood would be elevated. So when a doctor draws your blood to find out what’s wrong with you, it’s these levels of white blood cells that will help them narrow down the cause of your problem.
The last part of blood is called plasma. This makes up most of your blood volume and about 90% of plasma is simply water with another 8% of plasma made up of proteins, such as proteins like Albumin which helps move molecules like calcium and medications through your blood, antibodies that help with infection, and fibrinogen and clotting factors that help with the clotting of your blood. The other 2% of plasma contains hormones like insulin, electrolytes like sodium and potassium, and nutrients like sugars and vitamins.
Now that you know what’s in your blood and basically how blood works, spill it sparingly. Your body needs almost every part of it! One last tip from a paramedic to you- how to get blood stains out. If you spill or otherwise get blood on your clothes, just soak it in 1 quart warm water, 2 teaspoons of laundry detergent and 1 tablespoon of ammonia for approximately 15 minutes. Then remove all the ammonia and launder it normally. (And note: don’t dry it until the stain is completely gone.) Bam! Your clothes will be blood free and you’ll be ready for your next fight!
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- The Red Juice in Raw Red Meat is Not Blood
- When reading about red blood cells, you might have heard of the term “hematocrit”. This is simply the measure a doctor uses to determine the percentage of your blood volume that is red blood cells. If the total volume of your blood was 48% red blood cells, then your hematocrit would be 48.
- You might have also heard the term “serum”. Blood serum is simply everything in your plasma except the fibrinogen and clotting factors.
- Blood type is an inherited trait passed down by your mother and father. What type you are will depend on the types of blood your parents have. O+ is the most common blood type, while AB- is the least common . Different ethnic groups have higher percentages of specific types. For instance, Hispanic people tend to have higher numbers of type O blood. Asians tend to have higher B’s.
- If you don’t know your blood type and need a transfusion quickly, before your doctor can figure out what type you are type O- red blood cells can be given to most people and type AB+ plasma can also usually be given. Because of this, people with these blood types are considered universal donors.
- Red blood cells do not contain a nucleus. They can also change shape. This helps them fit through the many different, smaller, blood vessels throughout the body. The lack of a nucleus and the damage the cell receives when squeezing through small blood vessels, unfortunately, limits the amount of time the cell can survive. The average red blood cell lasts around 120 days. Should your body not replace as many red blood cells as are destroyed, you could have a low hematocrit. This is also known as anemia.
- The life cycle of white blood cells varies with the type of cell. They can range from as little as 12 hours to as long as several years. If you consistently have a high number of white blood cells over time, you might have Leukemia. Leukemia is a cancer of the blood. A patient with it can have a WBC count of around 50,000 per microliter of blood!
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