Vampires Can Suck It

Last week, we were going through blood and the circulatory system during Biology lessons. While I stared at the ceiling, unable to sleep yesterday night, I suddenly wondered how accurate the portrayal of vampires’ blood drinking habits are.

Okay, the basic rules and reasons for why vampires need to drink blood is because they are not alive, and, hence, are incapable of creating their own blood for themselves, right? So, discounting the fact that not being alive probably means that they wouldn’t need food or air or water, since they won’t be respiring, the red blood cells in the blood have the main function of transporting oxygen and carbon dioxide.

Since red blood cells have a life expectancy of 120 days, vampires only actually need to feed once every 120 days. And if their livers don’t function, they can actually last longer, even if the red blood cells won’t be as effective at their job as they were before the ‘expiry date’. So, that means that the symptom for ‘bloodlust’, where the vampires crave blood, would only be that they are extremely exhausted as they do not have enough oxygen or other nutrients to allow their body cells to respire and function.

Actually, doesn’t that make vampires normal humans who can’t produce their own blood?

Well anyway, the other big problem would be blood type.

A basic overview on blood type would be that your blood type is determined by the antigens present on the surface of your red blood cell, and the antibodies in your blood plasma. There are two types of antigens and two types of antibodies, and the combination of which antigen you have will determine your blood type.

Blood Type       Antigen       Antibody
.     O                   N.A.            A&B
.     A                     A                  B
.     B                     B                  A
.    AB                 A&B             N.A.

So, above is the chart of which blood type has which antigens and antibodies. A basic summary of what happens when you transfuse the wrong blood type: the antibodies present in the plasma of the person receiving the transfusion would bind to the antigen on the red blood cell of the blood they are receiving, causing the blood to clot, and, at the same time, the antibodies present in the blood being transfused would bind to the antigens on the blood in the person who is receiving to the transfusion, and the end result is a lot of blood clots that would kill the person because the blood vessels are all clogged up.

.        O       A       B       AB    [Donor]
O       ||        /         /         /
A       ||        ||        /         /
B       ||        /         ||        /
AB      ||       ||        ||        ||

|| indicates that the blood won’t clot.
/ indicates that the blood would clot.

From the chart above, you can see that the AB blood type is the universal receiver, while the O blood type is the universal donor. Where’s the +/- ? Well, that I’ll leave out for this, we’ll just deal with the four main blood groups first.

Okay, now that we have all the pesky little knowledge needed out of the way, let’s go back to vampires. Actually, now that you know all this, can’t you see what the problem is? A vampire cannot simply go around biting people and taking their blood, because taking the wrong person’s blood will kill them. I’m thinking of the way this works as vampires basically receiving blood transfusions from normal people via biting them and swallowing their blood, so, much like during blood transfusions, if, say, vampire John Doe is of blood type A, and he got unlucky, chancing upon a victim that just so happened to be in the 3% of blood type AB running around the place, his blood would clot up and he would die.

So those stories where the vampires run around willy nilly and catch victims off the streets and just drink from them without checking their medicinal records? Well, the vampires are extremely, extremely lucky that everyone they’ve been drinking from has a blood type that won’t kill them.

Which brings us to another problem: vampires can’t produce their own blood. Thus, what would their blood type be? Well, my theory is that their original blood type would be dependent on either their blood type before they died, i.e. the blood survived the time during which they were dead, or it depends on the blood type of the first person they draw blood from.

But their blood type would change, since they cannot maintain the production of the blood cells and blood plasma to keep the blood type consistently whatever type it is. They depend on their prey for blood, after all, so wouldn’t the blood type simply change to become the blood type of the person whose blood they had last ingested?

In which case, they’d have to be constantly aware of their own blood type and use it to find the potential ‘donors’. And that just makes it so much of a hassle, being a vampire, doesn’t it?

And I’ll just stop here tonight, since, well.

Hope you had fun reading this!

Suffocating in Air

Continuing on yesterday’s post, people drown and suffocate in water because of certain reasons. Why, then, do fishes survive just fine in water, but suffocate when you leave them on dry land? Well, let me ask you, have you seen a fish’s gills before? Go and look at it. See, a fish’s gills are made out of filaments that are supported in the water, helping the fish get the oxygen they need from the water as they swim around, however, given that they are supported by water, when you take them out of the water, they’ll collapse. It’s kind of like when you leave the swimming pool and your hair instantly sticks to your head, when in the water, they were voluminous and spread out. Thus, out of the water, after the structure has collapsed, the amount of surface area is greatly reduced and their oxygen intake is lessened. The bigger reason that the fishes would die, though, is that their gills would dry out. As mentioned previously, the oxygen needs to be dissolved before it can be diffused through the respiratory surface, and, as the fishes had always been in a wet environment that keeps their gills drenched for them, out of that environment, they have no mechanisms to help them keep their gills wet to allow them to intake oxygen. Hence, as their gills slowly dry out, they get lesser and lesser oxygen, resulting in them slowly suffocating. It’s dehydration that’s actually killing the fishes, in that sense, as the dehydration results in them being incapable of breathing. So, there you go, the reason fishes suffocate on dry land.

Inspiration, Expiration…

During Biology today, one of my classmates asked my teacher how, exactly, does a human drown. His logic, based on what we were being taught, was that since oxygen has to be dissolved in the thin film of moisture covering the respiratory surfaces before it could be diffused in, having the water would help, too, wouldn’t it, because the oxygen is already readily dissolved? According to our teacher, though, that is not the case.

So, how do people drown? It is due to both having insufficient Oxygen (O2), and having too much Carbon Dioxide (CO2) in our body.

See, when you hold your breathe, the amount of CO2 in your body builds up, because you’re not breathing, thus, you’re not allowing the CO2 to be diffused out. When that happens, your brain will automatically signal for you to breathe, and you would breathe, involuntarily, no matter what. Why would your brain signal for you to breathe? That’s because CO2 and water together forms carboxylic acid, which gives you H+ ions that will lower the pH. As humans, our bodies are incapable of functioning properly when the pH gets too low, thus, your brain will automatically get you to breathe anything, in an attempt to help you get rid of the CO2, and, in the process, get you more O2.

Which brings us to the second point: O2 has low solubility in water. As such, having a lung full of water actually means less oxygen for us than if we simply had a lung full of air. The other problem that comes with having a lower concentration of O2 in water than in air is that diffusion works via a concentration gradient, where molecules will diffuse from a region with a higher concentration to a region with a lower concentration. This is why we breathe, or, as my teacher calls it, ventilate.

Ventilation allows us to get a new supply of air, helping us to readjust the concentration gradient such that there will be a higher concentration of O2 in the air than in the blood, and a lower concentration of CO2 in the air than in the blood. With water, however, as it is both heavier and denser than air, being human, our lungs are not strong enough. They cannot ventilate water, thus, on top of having an already low concentration of oxygen in the water that we breathe in, we cannot exhale it to replace it with a new load of water that might have slightly more oxygen in it than one that has already been drained as much as it could be by us.

Thus, when you are drowning, if you try to hold your breathe, you would eventually be forced to start breathing, less you die of having your body being acidified, but if you don’t try to hold your breathe, you would not have enough oxygen, and would thus suffocate to death.

A piece advice here: if you don’t know how to swim yet, go and learn now. It will save your life someday.