A clumsy, oddly looking animal slowly (very slowly; 13 mm per hour!) crawls on the glass. It, rubber-like, compresses itself into a tight knot or extends tongues of some sort to its' sides.
The legs slash tongues move forwards, the liquid body of the beast transfers onto them. New growths crawl further and by pouring into them, the animal `moves' onto a new spot. Thus, it travels in a water drop that we scooped from a pond. It is an amoeba, a microscopic single-cell animal, and we are observing it through a microscope.
Treat this strange creature with respect: this, or something respectively similar, was the appearance of the ancestors of all life on Earth 2 milliard years ago. Moreover, even now, cells that are very similar to amoebas in appearance live in our organism: leucocytes - white blood cells.
Now the amoeba encountered a green sphere - a single-cell alga. It grabs the cell with its' `legs', surrounds it from all sides with its half-liquid body, and the microscopic alga is already inside the amoeba! Thus, an amoeba feeds.
Moreover, how it breathes?
Every one to two minutes a tiny drop of water appears in its' protoplasm. It grows, inflates and suddenly bursts outside, flowing out of the animal's body.
This is a pulsing vacuole - a `wandering heart' of an amoeba: it appears first in one place, and then in another. The water, which penetrates the body of the tiny creature, collects inside of the vacuole. The vacuole, contracting, pushes the water outside, back into the pond. Alongside water, the oxygen that is dissolved in it gets into the animal. Thus, the amoeba breathes.
Therefore, the amoeba has no blood. Oxygen that is necessary for breathing is brought to it, penetrating its' protoplasm, the sea or fresh water, (depending on where the amoeba lives: in a sea or in a pond). The water also takes outside products worked out by the amoeba, the excess of its' body processes.
Gradually, single-cell organisms evolved into multicellular ones. Sponges, jellyfish, and sea anemones already inhabited 600 MYA the sea. Their little-changed descendants survived to our times and when we cut them up, we can notice that those animals also have no blood. They get oxygen straight from seawater. It surrounds them from the outside and penetrates through the multiple pores, filling all of their tissues. Hence, a jellyfish is so transparent: it is `filled' with water.
Seawater is the cradle in which life was born, it served for a long time for its' children as a transportation means, giving their tissues oxygen that is necessary for life.
However, the animals developed, grew more complex. Water no longer could so simply, as in case of sponges and jellyfish, penetrate with its' precious cargo to all of the complex organs of the new animals. In addition, here a marvelous transformation occurs, (not immediately, of course, but over millions of years): the insides of animals develop their own `plumbing system'! An entire network of channels, filled with liquid, which spreads oxygen all over the entire body.
For the first time, this blood circulation, or initially, this `plumbing' system appears in ancient worms. They did not yet have real blood: their blood vessels were filled with ordinary, only slightly altered, seawater.
Gradually, during the course of the long evolutionary process, the concentration of unnecessary sea salt decreased in it, and new substances appeared. Eventually, the `captured' seawater became a miraculous liquid that now circulates in our veins and arteries. Thus, the world acquired blood.
It can be said that our ancestors the ancient amphibians, emerging 350 MYA onto land, took in their arteries a particle of the old homeland: seawater, transformed into blood, which once permeated all of their tissues. Even now, blood and other internal liquids of many, even terrestrial, animals contains sea salts - approximately in the same proportions as in the ocean water.
In the blood of higher animals - say, birds or mammals - it is hard to find open traces of seawater. That is obvious. For blood, this wonderful juice of our organism, now executes many different goals. Through thousands of conduits and microscopic streams, called the capillaries, does it spread throughout our body. All cells receive from it a nutritious `soup' from it, which had been digested by the intestines and the stomach, and give back unnecessary substances and carbon dioxide. Glands of internal secretions fill the blood with hormones that regulate the work of the organs. In short, the blood spreads, alongside oxygen, multiple sorts of salts, acids, vitamins, ferments, nutritious products and products of decomposition, and etc., and etc., Therefore, its' own composition is very complex.
WHY IS BLOOD - RED?
Even under a microscope, nothing is seen in blood, only a deep red shroud. However, if blood is diluted 200 times and then dropped onto a glass slide under a microscope, then you will see a picture that delighted Levenguck of the Netherlands: he was the first person to ever see it.
This is what he saw: a multitude of yellowish-pink disks with convex edges and a concave middle.
Those are the famous erythrocytes - red blood cells. They play a very important role on the arena of life: it is the erythrocytes that consume oxygen in lungs and distribute it to the further consumers. Back the microscopic `carts' do not arrive empty: they take carbon dioxide from the tissues and deliver it into the lungs, where the carbon dioxide is exhaled.
Erythrocytes lack nuclei - they do not live for long: 127 days. However, they have a strong outer membrane and a firm internal carcass (the stroma) that supports their trademark discus shape - that of a transporter. All the in-between spaces of the carcass, like sponge pores, are filled with red `paint' - haemoglobin.
Aside from haemoglobin, the tiny red blood cell (it is only 8 microns across - eight thousandths of an mm) is literally stuffed with multitude of substances.
Here you have potassium, magnesium, zinc, nitrogen, oxygen, glucose, vitamins, sodium, calcium, aluminum, various ferments and fifty thousand types of antigens!
However, the most important substance in a red blood cell is haemoglobin, of course, (almost one third of the overall weight). It is a complex protein, whose molecule is connected with four atoms of iron. Iron contacts globin, birthing haemoglobin not on its own, but with a group of elements that accompany it and call a haem. In its' nature, haem is close to chlorophyll.
It is because of iron that our blood is red in color.
After all, many substances that contain the so-called oxidized iron consume rays of the yellow-green portion of the color spectrum and reflect the red ones. Therefore, they are colored in red. On the other hand, wustite gives a green color.
All the vertebrate animals, as well as the earthworm, the leeches, the housefly and some molluscs have oxidized iron in the `colored' blood proteins. Therefore, their blood is red. Some sea worms have chlorocruorin in their blood alongside wustite in there hemes, instead of haemoglobin, and so the blood of those worms is green.
There are animals in the world that are pure aristocrats judging by their blood color. They are scorpions, spiders, and cephalopod molluscs, (the author does not joke!). Instead of haemoglobin they got hemocyanin, and it contains not iron, but copper. Copper colors their blood blue (in the veins) and almost indigo (in the arteries).
Oxygen, in the blood, joins with metals, (copper, iron or manganese, as in case of some snails). However, this union is not lasting: in places, where oxygen is plentiful, (for example in the lungs), it briefly unites with haemoglobin. Moreover, where there is not enough of it, (for example, in the brain, or in the muscles), metals break with oxygen. Instead, red blood cells load up here on carbon dioxide, to give it up in the lungs.
By enriching itself with oxygen or giving it up, the haemoglobin molecule either compresses or expands. The famous specialist of haemoglobin, Dr. P. Perutz, writes, "I want to call it a `breathing' molecule, but here the paradox is that it widens when releasing oxygen, and not when consuming it". Without haemoglobin, blood dissolves in itself 70 times less oxygen.
Carbon monoxide, which is plentiful in exhaust gases and in poorly working furnace, connects with metals of respiratory proteins even faster than oxygen does. Moreover, it very unwillingly breaks-up with them: only after several hours, and only if the affected person gets some fresh air. When air, which we breathe, contains only half a percent of carbon monoxide, the latter occupies half of haemoglobin in our blood and keeps the oxygen out. In addition, a person can choke.
In addition, in order for a person not to choke as an embryo in the mother's loin, nature gave human embryos the supersensitive, fetal haemoglobin. It literally races to contact oxygen, literally pulling it out of mother's blood that flows to the placenta, though the partial pressure of the oxidizing gas in it is quite small. Having been born and safely survived for five months, the baby loses all of its fetal haemoglobin and creates the `adult' haemoglobin in its' blood vessels.
Only humans and mammals lack nuclei in the red blood cells. Therefore, they acquire much more haemoglobin than the red blood cells of the lower animals.
Really, it is chlorophyll, which has iron instead of magnesium. The same, very busybody, family of `colored' proteins contains also the cytochromes, aka the breathing ferments, which transfer electrons from oxidized nutrients to oxygen in the mitochondria of animals and plants. The energy that is released at that time enriches ADF, turning it into ATF.
Carbon dioxide connects not with metals, but with globin and blood plasma.
200 THOUSHAND KM OF ERYTHROCYTES
How much oxygen can a haemoglobin molecule take? Only eight atoms. However, each red blood cell has 265 million haemoglobin molecules. Moreover, each cubic mm of blood has 5 million red blood cells. In the entire 5 l that circulate in our veins and arteries there 25 trillion erythrocytes!
If we put them all in a row, side to side, how far will our red blood cells go?
1-2 km?
Alternatively, maybe, from Moscow to St. Petersburg?
No, to the Moon! Almost 200 thousand km!
If some meticulous sceptic, not trusting the calculations, will decide to count all the erythrocytes in human blood under a microscope, they will spend, on this hopeless business... 1500 years!
Every second, our red -->
In the breastbone, shoulder blades, skull, backbone, and joints. There is also yellow marrow. It stores fat. marrow[Author:DK] undergoes 10 million of mioses and gives birth to 10 million red blood cells. Every second the `conveyors' of marrow's RNA create 650 trillion of haemoglobin molecules!
It is an immense labor. However, undoubtedly you will feel even more respect to yourself, to the miracle that occurs in our bones, when you will learn that the marrow produces not only the erythrocytes, but also the thrombocytes (400 milliard per 24 hours!) and the leucocytes, (30 milliard): monocytes, neutrophils, eosinophils and basophils. Only the lymphocytes are born in the spleen, the tonsils, and the lymphatic knots.
Monocytes, lymphocytes, neutrophils, eosinophils and basophils - they all are leucocyte varieties, i.e. the white blood -->
Most numerous in our blood are the neutrophils (60--700 %) and they all die within 3 days after irradiation by the gamma rays (for example, during nuclear explosions), leaving our organism defenceless before a microbe attack. cells [Author:DK] .
They all look different, but all of them have nuclei, all are colorless, and all crawl like amoebas, and all are brave soldiers: protecting our health for 24 hours, they battle germs without vacations and truces. In addition, if a person is alive and not sick, then they primarily owe this to their leucocytes. Moreover, as the soldiers do, they do not live for long: 2-4 hours, (and lymphocytes only for four hours!). Almost all of them die on battlefields, from `overeating' bacteria.
If, having broken past the protective shields of skin and mucous membranes, germs do invade our bodies, the leucocytes immediately race there via the blood vessels with the blood flow and `on foot', i.e. on their own power. They reach the closest infested capillary spot, and then, working their -->
Pseudopods - false legs - are the name of the tongue-like growths - amoeba legs, which appear and disappear. Pseudopods [Author:DK] as if they were arms and legs, they crawl through the capillary wall into the tissue space between the cells.
Like an amoeba, (i.e. fast or slow?), they move between the cells. Probably this is fast - three times faster than an amoeba moves: 3 cm per hour. That is a lot for such tiny cells. If you count the covered distance not in cm, but in the diameters of the mover's body, then the conclusion is that the leucocytes rush to the battlefield almost as fast as a racing horse would.
The leucocytes attack the germs with all the rules of the art of war: with a tight interaction of all types of the leucocyte army. Some military subdivisions of leucocytes generate poisonous substances that kill bacteria. The second, so to say, de-gas - they disarm the bacteria poisons with their -->
Antibodies, special proteins, disarming antigens, (of various foreign bodies that enter an organism), are created mainly by lymphocyte-like plasma cells of spleen, lymphatic knots and intestine. antibodies[Author:DK] . Finally, the third, (neutrophils and monocytes), grab with their pseudopods the live and dead bacteria, (remember how the amoeba grabbed the alga!) and `swallow' them, (as the biologists say - they phagocyte). Swallowing enough bacteria, the leucocytes die. A neutrophil, before dying from the self-sacrificing gluttony, will eat and digest 25 bacteria, and a monocyte - an entire 100!
The place, where a battle between white blood cells and germs is taking place, inflames and reddens from blood flow with more and more new fighters. Dead cells, struck down by bacteria, live and dead leucocytes, fill with themselves, i.e. - with pus, the battlefield.
OUR POOR HEART - A SUPER-POWERFUL PUMP
We say: "Blood ebbs, blood flows..." Who pushes it? Who, (or what), pushes it, forces it to flow?
This wonderful engine, the most perfect motor in the world is our heart.
At first, the circulatory, or, initially, the `plumbing' system appeared in the world alongside the ancient worm species. However, they still had no heart. Rather, their entire dorsal artery was their heart. Its' walls, rhythmically contracting, pushed blood through the vessels.
The first heart appeared in the world alongside the worms' descendants - the so-called brachiopods. They live in bivalve shells and resemble, (superficially), shellfish or... the Roman torches.
When the worms, evolving, produced the molluscs, they already had a two-chambered heart with an atria and a ventricle.
The animal world developed, the heart too was perfected. Verily, we have two hearts - the left and the right, though they are combined into a single organ.
After all, blood goes through our body in two routes: a greater and a lesser circle. The greater circle is the journey from the heart, (its' left half) to the various organs and tissues and back, (into the right atrium). In the lesser circle, (from the `right-side' heart) the blood rushes into the lungs. There it discharges the unnecessary to us load - the carbon dioxide - and receives a gas that is very useful to us - oxygen.
Two septums, the anterior longitudinal sulcus and the posterior intraventricular sulcus, crosswise separate a human heart into four chambers. From them, the blood from the upper chambers, (the left and right atria) goes into the lower ones (the left and right ventricles). Via rhythmical contractions, blood goes from the atria into the ventricles forever in a single direction - downwards. Valves do not let it go upwards. This clever construction resembles a doorway that can open only in one direction. However, when it is returning to the heart, the blood from the organs that are located below the heart must go upwards. Different `doors' serve this purpose: they too open only in one direction, but now from downside upwards. They are valves of veins - of vessels through which blood goes to the heart.
From the heart, (its' left half) it first flows through the aorta. It is an elastic, because of the muscles, pipe with a 3 cm diameter. The further from the heart, the more the aorta branches, sending into all the organs its' offspring - the arteries. In addition, the further from the heart, the smaller and the smaller the arteries' caliber gets. Penetrating the tissues of the organs, the arteries, branching, turn into the smallest blood vessels - the arterioles. Here, however, the fragmentation of the blood vessels does not stop: the arterioles give rise to a multitude of `hair-thin' vessels - the capillaries.
A capillary wall is built in a special way and resembles a sieve. Through the holes between the cells, which form only a single layer, oxygen and nutrients freely leave a capillary, (leucocytes too go through them, pushing cells aside to widen the hole). Through the capillary pores, carbon dioxide and waste by-products enrich blood. A capillary does not end anywhere, it does not vanish suddenly, but fusing with its fellows, it gradually increases its' caliber and becomes a venae. Venae join into veins. In addition, the latter bring blood once more into the heart. Thus, the circles of our `circulation' are closed everywhere.
A human heart pushes with such force blood into the arteries, that it circumnavigates the body and returns to the starting point on average within 20 seconds!
In the arteries, blood covered half a meter within a second, in the veins - 6 to 8 cm, and in capillaries - only a single mm. Within the 24-hour period, our `poor' heart utilizes the strength of 270 horsepower! Each second it sends 100 g of blood through our vessels, and within the 24-hour period - 10 thousand litres!
This means that within the 24-hour period a heart does the work of an entire loading brigade, which load 12 tonnes of some load into a cargo wagon.
A heart does not have an eight-hour working day: it pushes blood constantly - night after night, day after day, almost from the very conception and until death. If it stops for 3-4 seconds, a person faints. Moreover, if it will not be for several minutes - death will arrive.
Within 70 years of life, the heart, contracting 2 milliard 600 million times pumps 250 million litres of blood! A super-powerful escalator that raises a loaded cargo train to the top of the Everest Mountain can do such a job. It is an amazing workload, for the motor itself is undersized, it itself weighs only 300 g.
It is both undersized and economical: during the entire lifespan, only 3 quintals of sugar `burns down' in it. The world does not know a more `humble' engine. It should also be noted that it works without stopping day and night, it never overheats and no one repairs it with either a temporal or a permanent repair works. Just a small pause in one third of a second between each working move is enough for it to both rest and load-up on fuel for the new contraction, which with the former force pushes blood through the arteries.
WHY DO WE NEED THE SPLEEN?
When it was said that the blood vessels in our body are completely interlocked, one joins another without an abrupt end anywhere, it was not mentioned that there is an exception to this rule. The spleen, a big smooth `bean' in the left half of the ribcage, submits to the law of the enclosed circulation only halfway. There is a stiff self-containment of the capillary network in the spleen, but in places, it is broken and blood freely pours into the organ's tissues. The spleen absorbs it as if it was a sponge, and stores for the right moment. This moment can come during physical exertions. Then the spleen sharply contracts, (who doesn't know the sudden pain in the left side when you are running quickly?), and sends an extra portion of blood into the blood circulation. At this time, the `bean' seemingly does its' own blood transfusion.
The ancient doctors called the spleen `an organ full of mysteries'. Back then, it was thought that `the spleen juices' put people in a bad mood. There is a reason as to why the word `spleen' in English language means both the organ in question and a `bad mood'.
If poets are to be believed, then the spleen hurt even the famous `puss in the boots'. As it is known, this cat stayed in court `and was given ranks'. Sometimes he did catch mice, `to entertain himself and to break the spleen that he developed in his old age in court, with the memories of his better days'.
To this already unhappy reputation of spleen, often another joyless word is added - the `cemetery'.
As it was said in a different place, in an adult human blood, 450 milliard red blood cells, 30 milliard white blood cells, and over 400 milliard thrombocytes die and get replaced daily. This entire army of doomed cells, passing through the branching course of the spleen, remain in it for a long time. The blood flow here is slowed, and the dying, worked-out blood elements fall apart in the spleen. Then they dissolve and the organism begins to build new cells from them.
In the same way, the spleen `pulls' out of blood the harmful germs and other dangerous elements, and for this useful activity, it is also often called a `filter'.
There is another peculiarity in the spleen: it controls the activity of the blood creating `conveyor belts' of the marrow. As it was said elsewhere, the marrow creates all of blood's elements, except for the lymphocytes. But the marrow itself cannot determine the quality of its' production: it is ready or not yet complete. However, the spleen understands this very well and does not allow releasing the incomplete blood cells into circulation, it halts them.
In addition, there is another mystery of the spleen: no matter how its' service is important, but it can be removed without ill effects. Moreover, sometimes people not only feel fine without the spleen, but also even recover from certain diseases.
There is such a disease, when a human's skin gets covered in black spots, as if it was a leopard's hide. Regretting their miserable life, such a person weeps bitterly, and weeps not tears, but... blood. Bloody tears and bruised skin are born by one reason: there are enough thrombocytes in the blood.
They are tiny spherical cells that lack nuclei and in the diameter, they are three times smaller than the red blood cells are. 5 l of blood has 1.5 trillion of thrombocytes. Moreover, when their number drops, then the blood clots poorly, a person suffers from blood infesting and over pouring into their skin and various organs. As it was said, the spleen controls the blood-creating works of the marrow. One of the reasons as to why thrombocyte numbers fall down may be its' too-stern control.
The thrombocytes are the numerous `children' of giant maternal cells called the megakaryocytes. A megakaryocyte dies, giving birth to the thrombocytes. It happens thusly: with its pseudopods, the huge cell crawls into a vein capillary and begins to pull from its' body one after another tiny plate until all the protoplasm is spent. Only the nucleus is left. Unnecessary, it withers and gradually dissolves. Naturally, if the spleen surpasses its duties and slows the work of the bone conveyors too much, then the thrombocytes will stop being born and join the blood in the right amounts. The removal of the too-meticulous controller cures the patient.
BLOOD GROUPS
The idea that you can transfer blood from person to another is as old as the world itself is. It happened that the realization of this idea brought salvation to people, but more often, a human with transferred blood, died in suffering.
The Austrian doctor Karl Landsteiner was the first person in the beginning of the 20th century to understand as to why failures and successes happen in blood transfers.
Once, he mixed on a plate, blood drops of his six colleagues, and looked into the microscope. What he saw there, was thought-inspiring... On the plate, some erythrocytes grouped together and resembled grape clusters. However, the others did not and thought the lenses it could be seen that they were lying separately, by themselves.
Landsteiner decided that the `grape clusters' or the erythrocyte grouping happened when there was a meeting of special erythrocyte substances with another substance, which flows in the liquid part of the blood, that is, in the plasma. The erythrocytes' substance Landsteiner called the antigen, its' opponent in the plasma - the antibody, and the grouping - the agglutination reaction.
Moreover, it immediately became clear as to why a successful blood transfusion occurs only rarely. It seems that different people have different erythrocyte antigens. Their antibodies are different too. In addition, the agglutination occurs when incompatible antigens and antibodies meet.
Judging by what antigens and antibodies are there, the doctors separate human blood into four basis groups: 0, A, B, and AB.
In the 0 or the first group, there are no antigens at all. Therefore, this blood can be transfused into anyone: there is no agglutination, since no alien antigens will be introduced with the donor's blood.
The fourth group, AB, doesn't have any antibodies in its' plasma and therefore it can receive the blood of any other group, the alien antigens will not be `refused' by anyone, they have no enemies - the native antibodies. However, the compatibility and the incompatibility of the other two groups is somewhat more complex.
Human blood groups
Erythrocyte antigens
Plasma antibodies
Groups that can receive this donated blood
Groups that can donate this received blood
0 (I)
A (II)
B (III)
AB (IV)
-
A
B
A, B
A, B
B
A
-
0, A, B, AB
A, AB
B, AB
AB
0
0, A
0, B
0, A, B, AB
If the donor's blood is chosen beforehand in regards to the recipient's blood, then the blood transfusion is sage. It does not need saying as to how many human lives were saved by this discovery!
Some biologists ask a question: the inborn resistance of some people regarding some diseases is not related to the blood group?
Apparently it does. The statistics prove that people with the 0 group of blood more often have the intestinal ulcer, (England, Denmark, Norway, Austria, USA and Japan), with the AB group - cancer and the stomach ulcer, (England, Denmark, Switzerland, Italy, USA and Australia).
Spouses with different blood groups more often have sickly children too.
Chimera was the ancient Greek name of the so-called mosaic monsters - creatures that were made, as the sphinx and the griffin were, from bits of different animals. Usually, the chimera's body was a goat's, the tail - a dragon's, the head - a lion's, and its' jaws, like a flamethrower, emitted hellfire.
The biologists, (aside from one type of strange fish), call `the chimeras' not the fairy tale creatures, but quite real and not very scary, (some are actually quite attractive!) beings.
One such cute `chimera' woman, (known in the world of science as `miss M') once decided to become a donor. As it is proper, first her blood group had to be established. However, this simple job was not easy for the medics. In the blood drop of `miss M' that received the plasma with antibodies against the antigen of the group A, some erythrocytes grouped together, but most did not. Then they tried plasma with other antibodies, then with third, with fourth... Only when the doctors added the plasma of the first group, all of `miss M's' erythrocytes grouped together.
Apparently, not all of this woman's blood was her own; a significant part of it was from her twin brother. It is this blood mixing of twins that the biologists call `a chimera'.
The erythrocytes of embryo twins often go from one to the other and stay there. Children are born with mixed blood and keep on living thusly. However, the immigrants peacefully get along with the local erythrocytes and antibodies under the protection of the mother's body, i.e. before the birth. However, if they are acclimated there, then after the birth too, their peaceful coexistence continues.
Not all of the twins have `chimeras' in their blood, but only the so-called unidentical twins that come to be from two separately fertilized sex cells. Such twins have different inheritance; therefore, their blood groups can be different too.
The antigens, which `fill' the erythrocytes, are more numerous than the blood groups that are known to science, (and it is known that together with the subgroups they number more than four), and they all arise from the substance marked by the letter `N'. Erythrocytes of any group have the substance N. The mutations that even known shake our genetic inheritance, during the million years in which an ape `became' a person, has changed the substance N into the new, younger, (in evolutionary terms) antigens. Now they set the tone, determining the chemical properties of an erythrocyte, (and correspondingly the group into which the medics put it in). However, the ancient substance N, in one dose or another always exists alongside the new antigen.
The zero as a symbol of the first blood group means not an empty hole, but only that the erythrocytes have no antigens A and B. Instead of them, there is the substance 0 - also a proper group antigen.
The antigen A often reveals itself in three different personalities: A, A2 and A3. Moreover, another one of its varieties was discovered later - the antigen A4.
As it can be seen, the group antigens are `built' very strongly. Centuries pass, entire cultures and civilizations vanish from the face of Earth, but the antigen structure does not change.
The American scientist Boyd examined the human remains that were uncovered by anthropologists from the old graves of Mexico, Peru and Egypt, and established that almost all of the people that had inhabited these countries in the old days, was warmed by blood of group B.
The antigens, upon which the blood group depends, fill not just the erythrocytes. They exist in all the tissues and liquids of our body, except for the brain and the nerve cells. Some of them are dissolved in fats, others - in the water, (and then they leave us when we are miserable with our tears).
The author already said that an erythrocyte is literally stuffed with the antigens: it has more than 50 of them.
As a rule, each antigen is a matched by a hostile to it antibody and this `incompatible' couple forms a special system that is acceptably called by the first letter or by the last name of the person, in whose blood the antigen was discovered.
There is the antigen system of Kidd, Kell-Kelano, the Lutheran system, Daffy, the R-r system.
However, perhaps the most famous of them is the `rhesus' system. It was named so to honor the rhesus macaque: it was in its' blood that this now famous antigen, which was sought for long and so patiently, was discovered first.
THE RHESUS FACTOR
Right before the war, the scientists Levin and Stetson came close to solve the mystery of foetal erythroblastosis - a serious sickness of the newborn, when the children's red blood cell deteriorate.
It seemed that an evil fate pursued some families. Only the firstborn, (and even that was not always), was born healthy.
Levin and Stetson decided that the issue likes with incompatibility of antigens and antibodies. However, which specific ones, it could not be determined at that time.
This ill-fated antigen Rh, or the Rhesus factor, was first discovered in the blood of the rhesus monkey, and then - in people. About 85% of Europeans carry it in their erythrocytes: as they say, their blood is Rhesus-positive. However, the other 15% have it Rhesus-negative, i.e. the lack the antigen Rh.
It can happen, (and it often does!) that the husband has the Rhesus factor in his blood, and the wife - no. Then, if the child inherits the mother's blood, (i.e. Rhesus-negative), they will be born healthy. However, if they inherit their father's Rhesus-positive blood, then the family will have a tragedy, known scientifically as the Rhesus conflict.
If in the placenta, which replaces for the embryo both lungs and stomach, there is some defect, then the embryo's blood can contact the blood of its' mother. And if the new blood carries the Rhesus factor, and the mother lacks it, the following the biological law of `rejecting the alien', her leucocytes will immediately produce and saturate the blood with antibodies in regards to the antigen that is new to them.
Later, when the woman begins to bear her second child, those antibodies will through some defect in the placenta penetrate the embryo's blood and cause the foetal erythroblastosis. Essentially, this is the same reaction that Landsteiner watched for the first time on his petri dish: the antibodies, attacking the antigens, cause the erythrocytes to group together. By doing so, they self-destruct.
In addition, if the case is intense, then the embryo loses so many blood cells that it dies before being born. However, more often, it is born and dies soon afterwards.
Now, when the causes of the Rhesus conflict are well known to the doctors, the newborn babies with foetal erythroblastosis receive massive, or total, blood transfusions, replacing, all, or almost all, of their erythrocytes with new ones. Moreover, the Rhesus-negative mothers are served by special clinics that are always ready to rescue their blood-`incompatible' children.
The incompatible Rhesus factor threatens death not only to the babies, but also to many of the grown-ups, who get underqualified blood transfusions. However, here everything is in reverse: it is not the person with the Rhesus factor who suffers, but the one who lacks it. It is dangerous to transfer Rhesus-positive blood to a person with the Rhesus-negative blood: their antibodies, attacking the alien Rh antigen, will cause the agglutination of the red blood cells, which is followed by death.
Each person with the Rhesus-negative blood should have on their chest, on another prominent place, a tattoo: `I'm Rhesus-negative!' so if that they get into trouble and they faint, (in case of some catastrophe), in a hurry to save them, they would not get Rhesus-positive blood into their veins.
However, apparently, there are still very few of such socially conscious people on the planet.
Not all of human races are threatened by the Rhesus-conflict. There are countries, where all of the population, (and not just 85% as in Europe), have the Rhesus factor in their erythrocytes. It is so well spread in Africa, that some also call it the African antigen.
The ill-fated `Rhesus' also does not threaten the newborn of Japan, and actually all of Asia's babies. It is known that the Native Americans, so to say, all have the Rh antigen.
On the other hand, the Basques of Spain, now considered, by many of Russian linguists to be the relatives of the Georgians that settled on the end of Europe, on the Pyrenean Mountains, can be very valuable donors: as a rule, they have Rhesus-negative blood. (If the Georgians are indeed the Basques of Caucasus as it was stated sometimes, then their Rh antigen should not be dominant either).
The human races, developing in isolation from one another, together with the various racial differences, have acquired, (via mutations), and kept in their genes, (via the path of natural selections) mostly some or other antibodies and antigens as well as the blood groups.
For example, in Western Europe on average only 4% of people have the fourth blood group, (i.e. AB); 47 - the A group (i.e. the second); 6 - the B group; 43% of Europeans are `universal donors: the have the 0 (first) group.
In Asia, there are completely different proportions: there is a prevalence of the `universal recipients' (AB) and the owners of the third group (B).
Some sci-fi authors in their non-scientific dreams of the impossible call humans the arrivals from other worlds. But, alas, humans are completely terrestrial creatures. With the roots of the substances that compose them, they are anchored deep into Earth's soil. An extra proof of their autochonous, local origin are the group antibodies and antigens in the human blood. They were made by nature long before the time when the ape brought forth the first human and the humans inherited them from their ancestors the animals.
For example, the antigen A is widely spread in the animal kingdom. It was found not only in humans, but also in the erythrocytes of sheep and pigs. The antigen B has a close relative in the blood of rabbits. Moreso: our blood relationship with the rest of the life on the planet Earth have outreached the animal kingdom and entered the kingdom of plants. Apparently, seeds of many plants possess substances, that are quite similar to the protective antibodies of animals. Boyd, one of the examiners of this surprising phenomenon, tells about his discovery so:
"I asked one of my assistants to buy dry Lima beans. Why I asked to buy precisely Lima beans and not ordinary beans or peas, I still do not know. However, if we have bought any other type of bean, we would not have discovered anything new. Lima beans were ground and dissolved in a salt solution. The resulted extract intensively agglutinated the erythrocytes of some people, and very weakly, or not at all, agglutinated the erythrocytes of others. It became clear to us that the agglutinin from the Lima beans is completely specific for the `A' antigen of humans'. (It is just as hostile towards it, as is the `a' antibody of the blood plasma).
To prop up the idea of the human `terrestriality' with newer facts, let us talk about the tissue antigens, substances that are universal to all life on Earth.
For example, an antigen in human heart muscles feels equally at home in the heart of apes, cattle, domestic fowl, hedgehogs, grass snakes and frogs. The antigens that settled down in the lenses of eyes are the same for many species of animals. The antigens of human hairs are close to the antigens of horns and hooves of horned and hooved mammals.
Therefore, if humanity did arrive some time very long ago from Mars or someplace else, then only on a Super-Noah's-Arc that had plenty of place for all lifeforms, which crawl, swim, fly, jump and flower all over the world.
However, not even sci-fi authors can imagine that.