It’s ALIVE!And oozing...
I hate being stuck with needles. They scare me, and that is a very generous understatement. However, post-needle-sticking, I do love watching as blood leaves my body through a transparent tube and flows into a plastic bag when I go to donate blood at Memorial Sloan Kettering Cancer Center. To put it succinctly, blood is awesome. If you just made a face, you’re ignorant. Granted, staring at your own blood is kind of weird, and I wouldn’t blame anyone who turns away while being stuck with a needle. However, at the microscopic level, your blood has got a whole lot of action going on, and it’s fascinating.
In actuality the majority of your blood, about 55 percent of it, is a liquid called plasma and it’s not red – it’s an unsettling sort of bruised yellow color. The rest of what makes up your blood, the cells known as formed elements, float around in the plasma.
The first and most well known cell that populates your plasma is the erythrocyte, or red blood cells. Referred to by people with PhD’s as RBCs for convenience, these cells are what give your blood its red color. Interestingly, not all animals have blood that looks red. Some crabs, for instance, have a turquoise-to bluish-color blood, some worms have green blood, and cockroaches have blood that is colorless. This seems a bit freakish at first, but really it is elementary chemistry.
The purpose of those RBCs is to transport oxygen to the tissues and organs in the body, and carbon dioxide away from those same organs. The way your cells accomplish this is by using an element from the periodic table to attract the oxygen, and make it stick to the RBC so that it can be transported to the necessary locations. In humans, the element that oxygen sticks to is iron. I’m sure you’ve all seen a rusty iron hammer or some other tool before. It’s got that reddish hue to it, because when iron is left out in the air, it naturally attracts oxygen to itself, and carries out a chemical reaction called oxidization. In other words, it rusts—or rather, you rust.
In other animals, like crabs, the periodic element that the oxygen attaches to is copper. Anyone who has seen the Statue of Liberty knows what happens when copper and oxygen mix. Hence the turquoise color of crab blood. The same process happens in green blooded worms, with a slightly different oxygen- attracting molecule. Cockroaches however, are slightly different. The reason for the lack of color in their blood is not due to a specific oxygen carrying pigment. It is because of the fact that cockroaches don’t even use their blood to transport oxygen; ergo, no color-binding occurs. Gross, but cool, no?
The next group of cells that make up your blood are leukocytes, otherwise known as White blood cells, or WBCs. There are many types of WBCs. Each performs a specific function to benefit the body as a whole. They pretty much function as an internal police force, complete with surveillance, infantry and special forces.
Natural killer (NK) cells are constantly on patrol, looking out for germs or mutated and diseased cells in your body. If they find any such cells, as their name suggests, they annihilate them. The NKs poke a hole in the germ cell and inject granzymes, which invade the enemy territory and push the germ’s self-destruct button, causing the pathogen to kill itself. After having done this, the NK cell will send out chemical messengers to the rest of the body saying “bring in the troops”!
The first responders to the message of the NK cells are usually WBCs called neutrophils. Like the NKs, they are also assassins. However, sometimes their methods of murder aren’t enough. When a neutrophil realizes that it’s fighting a losing battle, the duty becomes a suicide mission, killing itself and taking the germs with it. In the process of their suicide, neutrophils release another chemical messenger which calls for reinforcements, or lymphocytes and macrophages. These cells are monsters. They just eat their enemies. It’s pretty amazing.
Did you know fever is actually a good thing? When your WBCs see that your body is being invaded by hostiles, they send messengers to your brain to release something called a pyrogene (yes, pyromaniacs, it does mean fire), which tells your body to raise its internal temperature. This helps you, because most germs can only live and reproduce within a narrow temperature range. When your body becomes hotter, many of the pathogens die, and your body resets its internal thermostat to normal.
Face it, folks, blood is much cooler than you think!