the iron fisted rule of the human immune system
So I think my favorite part of human physiology, and this is true of my college days as well, is the immune system. Because it is fucking creepy. Or awesome. Depends on whether you're thinking about it as the system that keeps you from keeling over and dying or an anthropomorphic police state existing within the ecosystem of your body.
Let us take a journey into our immune system via the latter theory, because this will help me remember how everything works and also because, seriously guys, it's creepy.
So in our immune system we have B-cells, T-cells (T-helper and T-killer), Macrophages, and Neutrophils. There are a couple others but those are the four main ones. They all work together to protect us from outside invaders such as the common cold, bacterial infections, toxins, etc... They also work to protect us from our own bodies like in the case of cancer cells. As we know, this doesn't ALWAYS work but considering the volume of things we're actually infected with on a day-to-day basis, it's pretty damn good. In order to do this, the immune system is always patrolling, always on the prowl.
Our bodies are extreme xenophobes. Not only do they not like organisms from the outside world coming in and popping a squat, they don't like human tissue that isn't exactly like itself attempting to settle in either. That is why organ transplants, skin grafts, and blood transfusions can be so tricky. You must eliminate even the smallest danger of our immune systems recognizing those foreign tissues as not part of your body or else it is attacked and destroyed.
How does our immune system does this? Let's go down the list.
Macrophages and Neutrophils are the bodies thugs. They sneak in and out of capillaries into tissues and the nooks and crannies of our bodies looking for any free loader hoping to turn tricks where they don't belong. These cells are unique in that they are freely mobile and can move around at will to wherever it is needed or decides to wander in search of enemies. Bacteria, viruses, random molecules that don't look familiar, these cells will find them and eat them. No. Like seriously. They'll wrap their bodies around the offender, suck it inside of themselves, and digest them until they are nothing but spare parts to be excreted out of your system. While Macrophages and Neutrophils can engage in non-discriminate binge eating (innate immunity), they also help in eating and destroying stuff that's been marked for death.
This is where B-cells come in. B-cells produce little y-shaped particles called antibodies that stick onto pieces of proteins or other particles embedded on the outside of invaders. Our bodies produce trillions of variations of B-cells so that there's an antibody type for any conceivable type of antigen (or invader if you will). When a foreign particle wonders its way into our body, it will stick onto a protrusion on the B-cell made for it, like a key that falls into a lock. Once this happens, the B-cell is alerted to the presence of the invader and it immediately starts making antibodies which will then circle our bodies looking for more invaders that it can fit onto. Something like free floating door handles looking for the right key to attach itself to. Once these invaders have been marked for death they either die from not being able to reproduce in our bodies or a macrophage/neutrophil comes along to eat them after having recognized the random antibodies sticking out all over their bodies.
Kind of like being covered in paint. That will make the police want to chase you through the streets and eat you.
T-cells are like enforcers. T-cells are like B-cells in that they are created in trillions of variations. The ones that attack our own body are destroyed while the ones that attack foreign particles are kept. These T-cells patrol the body the way macrophages or neutrophils do and they regularly check the cells of our body or other B-cells to make sure everything is normal, everything is as it was the last time it came by. In order to do this the cell has to take a piece of something from inside itself and display it on its surface. The T-cell will come by and attach to it, make sure it's normal, and if it is the T-cell will move on. If it's not, the T-cell will alert a B-cell to produce antibodies and mark it for death. Or it will kill the offending cell itself. It would be like if the police came by your house ever few months to make sure your house is still your house and that strangers haven't moved in or that you haven't painted it a new color or that you haven't suddenly turned into a camel. To prove everything's cool you need to drag out a piece of furniture or stick your hand out the window so the cop can stand outside and feel it up and inspect it. If he doesn't like what he sees, he sends in a SWAT team to eat you and your house.
B-cells and macrophages can get a T-cell's attention by eating a suspect, chopping its body into little pieces, and wearing them like jewelry. Essentially they take something like a virus, break it down into its smallest components, and display those components (either proteins or structural molecules, etc...) on the outside of the cell for a T-cell to come by and inspect. If the T-cell decides, yes this is an unwanted guest, the T-cell will instruct the B-cells or macrophages to go ahead and attack.
The result is complete safety from intruders and infections and the means are brutal and ruthless.
Let us take a journey into our immune system via the latter theory, because this will help me remember how everything works and also because, seriously guys, it's creepy.
So in our immune system we have B-cells, T-cells (T-helper and T-killer), Macrophages, and Neutrophils. There are a couple others but those are the four main ones. They all work together to protect us from outside invaders such as the common cold, bacterial infections, toxins, etc... They also work to protect us from our own bodies like in the case of cancer cells. As we know, this doesn't ALWAYS work but considering the volume of things we're actually infected with on a day-to-day basis, it's pretty damn good. In order to do this, the immune system is always patrolling, always on the prowl.
Our bodies are extreme xenophobes. Not only do they not like organisms from the outside world coming in and popping a squat, they don't like human tissue that isn't exactly like itself attempting to settle in either. That is why organ transplants, skin grafts, and blood transfusions can be so tricky. You must eliminate even the smallest danger of our immune systems recognizing those foreign tissues as not part of your body or else it is attacked and destroyed.
How does our immune system does this? Let's go down the list.
Macrophages and Neutrophils are the bodies thugs. They sneak in and out of capillaries into tissues and the nooks and crannies of our bodies looking for any free loader hoping to turn tricks where they don't belong. These cells are unique in that they are freely mobile and can move around at will to wherever it is needed or decides to wander in search of enemies. Bacteria, viruses, random molecules that don't look familiar, these cells will find them and eat them. No. Like seriously. They'll wrap their bodies around the offender, suck it inside of themselves, and digest them until they are nothing but spare parts to be excreted out of your system. While Macrophages and Neutrophils can engage in non-discriminate binge eating (innate immunity), they also help in eating and destroying stuff that's been marked for death.
This is where B-cells come in. B-cells produce little y-shaped particles called antibodies that stick onto pieces of proteins or other particles embedded on the outside of invaders. Our bodies produce trillions of variations of B-cells so that there's an antibody type for any conceivable type of antigen (or invader if you will). When a foreign particle wonders its way into our body, it will stick onto a protrusion on the B-cell made for it, like a key that falls into a lock. Once this happens, the B-cell is alerted to the presence of the invader and it immediately starts making antibodies which will then circle our bodies looking for more invaders that it can fit onto. Something like free floating door handles looking for the right key to attach itself to. Once these invaders have been marked for death they either die from not being able to reproduce in our bodies or a macrophage/neutrophil comes along to eat them after having recognized the random antibodies sticking out all over their bodies.
Kind of like being covered in paint. That will make the police want to chase you through the streets and eat you.
T-cells are like enforcers. T-cells are like B-cells in that they are created in trillions of variations. The ones that attack our own body are destroyed while the ones that attack foreign particles are kept. These T-cells patrol the body the way macrophages or neutrophils do and they regularly check the cells of our body or other B-cells to make sure everything is normal, everything is as it was the last time it came by. In order to do this the cell has to take a piece of something from inside itself and display it on its surface. The T-cell will come by and attach to it, make sure it's normal, and if it is the T-cell will move on. If it's not, the T-cell will alert a B-cell to produce antibodies and mark it for death. Or it will kill the offending cell itself. It would be like if the police came by your house ever few months to make sure your house is still your house and that strangers haven't moved in or that you haven't painted it a new color or that you haven't suddenly turned into a camel. To prove everything's cool you need to drag out a piece of furniture or stick your hand out the window so the cop can stand outside and feel it up and inspect it. If he doesn't like what he sees, he sends in a SWAT team to eat you and your house.
B-cells and macrophages can get a T-cell's attention by eating a suspect, chopping its body into little pieces, and wearing them like jewelry. Essentially they take something like a virus, break it down into its smallest components, and display those components (either proteins or structural molecules, etc...) on the outside of the cell for a T-cell to come by and inspect. If the T-cell decides, yes this is an unwanted guest, the T-cell will instruct the B-cells or macrophages to go ahead and attack.
The result is complete safety from intruders and infections and the means are brutal and ruthless.