S:A: Kiosque / Hajime Saito's Simplified Elyria Medica / Simplified Anatomy and Physiology
Contents: Chapter 3: Physiology (*Heart & Blood, Liver, Kidneys, Lungs*), Brain
From Hajime Saito, the "Simplified Elyria Medica" in all its splendor.
Like the previous chapters, the aim of this chapter is to convey the overall big picture on how the organs are interconnected and the way the body works as a whole without having to delve in to excessive amounts of detail that overshadow the big picture.
In the absence of disease, damage or drug, the body exists in a natural state of balance known as homeostasis. Everything including endogenous substances (produced by and from within the body) and exogenous substances (introduced from outside the body), exists in the body within a certain concentration range deemed to be normal for an individuals’ specific circumstances.
Furthermore the functioning or performance of each organ system may also be quantified by the concentration of these substances with regard to specific reference ranges, and also be considered normal for a persons’ individual circumstances.
So what the hell does that mean? Simply put, everything is normal and how it should be BUT an isolated value for some laboratory test is meaningless without considering the specific circumstances surrounding the person from which the laboratory test was taken. Just because a result is high, low or normal means nothing if you know nothing about the situation.
Would you consider it abnormal for someone to have a pulse/heart rate of 150 beats per minute? Many people might automatically say “Yes”. While they may be correct, they could also be completely wrong, depending on the circumstances! Why? So this “person” may have just had a massive fright, may be in severe pain, has just run the 200 metre sprint or perhaps this is a sleeping 2 week old baby! All of which might make this value fairly normal!
What if I said an individual had a resting heart rate of 32 beats per minute! Again, many people would rush in and say “WOAH!!! That’s dangerously low!!!” Truthfully, in 99.99% of cases you would be correct, but what if I said this was the resting heart rate of Lance Armstrong? Well, that would then be considered normal… It’s still amazing, but it is absolutely normal, for him due to his level of fitness and the strength of his heart.
So context is important…..
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The heart pretty much does one thing and one thing only. It pumps blood around the body.
It’s actually more like 4 pumps in 1, rather than just 1 big pump. There are two smaller chambered pumps (atria) at the top of the heart and two larger chambered pumps at the base of the heart (ventricles).
The blood and blood vessels are like a river system used as trade routes for your body and organs so that the blood can transport and deliver essential nutrients, vitamins, electrolytes, energy/fuel and oxygen around the body to your organs.
It is this system which is also used by medicines, other drugs, poisons, toxins and venoms etc., to deliver their effects to the appropriate (and sometimes inappropriate) places in the body.
The heart receives blood which has already made its oxygen delivery to the body in the right atrium, while it receives blood which has stocked up on oxygen from the lungs again in the left atrium. The right atrium squeezes the blood in to the right ventricle which then pumps the blood to the lungs once it is full. The left atria collects the blood once it has gathered oxygen from the lungs and squeezes it in to the left ventricle which then pumps it around to the rest of the body, via the aorta (a very large thick artery), once it is full.
The heart may accumulate damage over time and when forced to work harder than intended for longer than intended. When the heart is damaged over time by disease or suddenly by traumatic injury, the main result is that blood is not pumped as efficiently.
This reduces the amount of blood and essential nutrients, vitamins, electrolytes, energy/fuel and oxygen being delivered to the organs. If the blood isn’t working properly then the amount of nutrients, vitamins, electrolytes, energy/fuel and oxygen able to be transported and deliver by the blood itself is reduced. While the heart can heal, the functional deficits experienced due to the damage may be permanent. Generally speaking, the lack of required nutrients, vitamins, electrolytes, energy/fuel and oxygen being delivered around the body produces a feeling or tiredness and fatigue (but so many other things can cause this feeling as well).