Hormonal Changes During Pregnancy

Hormonal Changes During Pregnancy

During the course of maternity, hormone levels that are secreted by the body (specifically, the placenta and corpus luteum) dramatically increase. This can have profound effects on the mother’s physical and mental state.

The hormone which sees the biggest spike as a result of pregnancy is estradiol, which is the woman’s primary sex hormone. Its name is related to the estrous female reproductive cycles that it plays an important role in regulating.

Prolactin, also known as luteotropin, also sees a significant increase. It is thought to be secreted around 20 times as much during pregnancy. This hormone is best known for giving the woman the ability to produce milk and is secreted from the pituitary gland.

Progesterone is another hormone that sees a vastly increased rate of secretion of around 7 times. Progesterone is one of the progestogens, a group of steroid hormones that are named the way they are for their role during pregnancy. It is produced by both the ovary and the placenta.

An interesting result of this hectic change in a woman’s hormonal profile is a change to the mood. Just as teenagers experience heavy so-called ‘mood swings’ as a result of puberty, pregnancy can have a very similar effect. In fact, the hormonal changes undergone by the body can be even greater, but likely because the adult is better adapted to coping with such changes, the behavioral changes witnessed are less severe.


The reason these hormonal changes can bring about changes to the mood is because of the way they change the levels of one’s neurotransmitters. The biggest swings in hormone levels take place during the first and third trimester. The first trimester is when the embryo is created, and the third is when the body begins preparing for childbirth.

Jessie Moran – Health expert and founder of Good Night Maternity Pillows.

The Marvels of Your Body Part 1

The Marvels of Your Body Part 1

If someone threw a handful of sand in your face, you would shut your eyes in an instant to keep it out. You don’t have to stop to think. In fact, you can’t help closing your eyes. The mere sight of something coming at your face makes you blink automatically. What actually happens is that a danger signal flashes along the optic nerve with which you see, but before that message reaches the part of the brain you see with, it has triggered off a message down other nerves to the muscles that cause a blink. This is known as a nervous reflex.

There are many other reflexes like this. For instance, if you meet a very appetizing smell, your mouth waters, and if you could see inside your stomach, you would see it become red and secrete gastric juice, in readiness for the coming meal. That is why it is such torment for a hungry person to see or smell good food he can’t get. The reflex just makes them hungrier than ever.

The point about reflexes is that they are involuntary. You don’t have to think about them, and it wouldn’t make any difference if you did think about them.

The examples just given are born in all of us, but there are other reflexes we acquire by habit or training.

When a baby learns to walk it has to think about it a lot, to put each foot in the right place and try to keep its balance. But once you have learned to walk, it becomes automatic and you can think of other things while you are doing it. The same thing happens when you are learning to ride a bicycle. For a few days it is very difficult, then suddenly the reflex comes, something seems to click, and you can ride without any difficulty whatsoever.

The same thing applies with swimming or learning to drive a car or play the piano. When you are learning such things, every movement has to be thought out slowly and separately, but once the proper sequence has been established in your brain it can be repeated indefinitely without giving it any attention at all. In fact, it works much better if it is left alone. Thinking about it and bothering whether you are doing it properly only makes you clumsy. And of course, it is very difficult if you have learnt a thing badly to unlearn, and learn again the proper way, because you have to get rid of the automatic response you have made before you can start making another.

That is why anyone who teaches you anything at all, from algebra to skating, insists on your learning it a step at a time in the proper way. It seems a great bore at the time, but it pays in the long run.

Teaching mechanics with human examples

Mechanics (Mathematics) is not taught just taught in advanced mathematics courses, but also at high school level. Many of the texts use abstract examples, or at best examples which are unrealistic or uninspiring (for example, your typical projectile motion question would involve an abstract projectile with no extra details). While they are useful in that they keep detail to the bare minimum that is necessitated, they do not make for an interesting class. Here, we discuss an example of a more concrete, real life example which makes it easier for pupils to appreciate the application of mechanics in the real world.

The standing vertical jump is a popular measurement of an athlete’s leg power, and it is one of the most effective ways of assessing changes in their physical state as the movement is isolated to a small area.

In Sports Science, the forces involved in a human vertical jump are numerous, but the problem can be broken down into smaller problems. It is a perfect illustration of a system of forces. These problems are typically introduced to these advanced level students in a Biomechanics course. In these advanced courses, it is not uncommon to have the student perform various practical exercises using a force platform, allowing them to make accurate measurements and produce very precise predictions and/or results. This is not necessary for the purposes of a high school mechanics class, but students are likely to find their work much more satisfying if they are using real-world data sets.

The vertical jump as a worksheet example has one added advantage over other ‘real world’ examples, which is that students can walk home having made their very own discovery about the vertical jump. It’s very difficult to apply any results from, for example, a problem involving a car or tennis ball, but easy to put their work into action with the vertical jump. The student is able to think about how to jump higher, by thinking about how forces relate to the form of their jump.

Medicine – Yesterday and Today (Part 2)

Part 1 can be found here.

Waging War On Germs

After some years it was discovered that there was no need to kill germs in the operating theatre unless someone took them there. By being perfectly clean, and boiling everything used, the wounds would still heal up all right without spraying the carbolic all over the place. This was called aseptic surgery and is the method still used today, when operations are not only painless, but free of infection too, and people are no longer frightened to go to hospitals.

But while it was perfectly possible and sensible to keep germs out of a hospital operating theatre, it just was not possible to keep them all out of ordinary rooms, and trains and cinemas, so people went on catching things. It should be possible to keep them out of our food and water, but that still isn’t always done, and people did and do catch things from what they eat and drink.

Actually, germ-free water was one of the first things tackled. Pure water stopped the epidemics of cholera which occurred in this country up to a hundred years ago. Apart from occasional accidents, it has stopped epidemics of typhoid fever, because the germs of cholera and typhoid are mostly carried in water. But things were different in war-time, when thirsty soldiers would drink from any old stream or puddle, and in the South African War typhoid was so bad that far more soldiers died of it than from wounds.

It was then that Sir Almroth Wright asked himself: Can’t people in some way be made immune to these infectious diseases? He noticed that often if you had a disease once, you didn’t get it again, and assumed that the body manufactured some antidote during his illness, which stayed there afterwards. His idea was that if you took some disease germs and killed them, they would not be able to multiply, so couldn’t do much harm, but might still have the power to cause a person to form the antidote. In this way he made anti-typhoid vaccine, and it worked so well that, although it was a bit too late for the South African War, it cut down typhoid in the First World War to a negligible amount, and typhoid vaccine has been used by the Army ever since. All soldiers, as soon as they join up, are inoculated.

It was hoped at the time that the same method could be used to protect people against all infections, but it did not work out quite as easily as that, and various modified methods had to be discovered before we had our present inoculations against diphtheria, tetanus, yellow fever, rabies and so on. Even now we are still searching for effective vaccines against many diseases.

So the position at the outbreak of the First World War was that we could prevent infection of clean operations, kill germs in our water, disinfect things which were covered with germs, inoculate people against typhoid; but once the germs had got into people, we were still rather helpless, because the sort of anti-septics we used, like carbolic, were just as poisonous to people as they were to the germs, so it was no use giving them as medicine.

The Miracle Of A Chance Discovery

It was then that doctors began to dream of some wonderful substance which people might be able to take which would kill the germs without injuring the patients. There was an inkling that this might be possible, because, for instance, quinine would kill the malaria germs without killing the patient, but it was a long search. The marvelous thing was that it was not the men searching for drugs who found the answer, but men looking for new synthetic dyes. Many dyes are antiseptics, that is they will kill germs, but it was found that some of them would not only kill germs but were fairly harmless to us.

Trypan Blue was developed in this way as a cure for African Sleeping Sickness, and later on it was found that a red dye called prontosil would kill blood-poisoning germs, and that a white powder obtained from this red stuff, which wasn’t a dye at all, was even better. It was called sulphanilamide and was the first of the many “sulpha” drugs which are now used by doctors in all sorts of infections.

The discovery of penicillin was another marvel in the fight against the germ. In every bacteriological laboratory, germs are grown in test tubes or in little circular glass dishes, on some sort of jelly mixture on which they thrive. The bacteriologist wants to study one kind, and does his best to see that only one kind of germ gets into each dish. But germs, especially moulds, float about in the air, and every time the cover is taken off a sish, there is a risk of an outsider getting in and spoiling the experiment.

This happened one day to Sir Alexander Fleming, and he was on the point of throwing the spoiled dish away, when he noticed that the mould which had got in was killing off the germs in the dish. From that one accidental speck of mould has been grown and made all the tons of penicillin since used all over the world.

But, of course, germs aren’t the only troubles doctors have to cope with. A good deal of their time is taken up with accidents and injuries resulting in broken bones. When a bone is broken, the limb goes a funny shape and hurts a lot. Unless it is handled very, very gently, the broken ends will move about and grate on each other. In the old days, the doctor had to judge from the change in shape and so on, what bone was broken, how badly, and how much it needed setting into place. How often he must have longed to be able to look inside and see just what he had to deal with. This seemed a very vain wish indeed, till that very marvel happened by the discovery of X-rays.

Medicine – Yesterday and Today (Part 1)

Medicine – Yesterday and Today (Part 1)

Modern scientific medicine dates only from about 1880, when Pasteur began to show that infectious disease was due to minute living microbes which could only be seen through a microscope. Before that, the treatment of disease was a matter of guesswork and folklore. Indeed, the old belief was that disease was either a punishment for sin or a possession by devils, so that doctors starved people, purged them and bled them to get these evil spirits out of their systems and, indeed, many people were much safer without a doctor than with one.

Nevertheless, throughout the ages, there have been brilliant men who have thought for themselves and refused to accept all the old beliefs and superstitions. More than 400 years before the time of Christ, there lived a Greek called Hippocrates, who is still called “The Father of Medicine”. He had the original idea that diseases were things which could be studied. He made careful notes about all his patients and was often able to tell which complaints would yield to treatment, and which would be fatal, and he studied simple remedies to see if they really did good or not.

He practiced in an island called Cos, and people came from distant lands to be treated by him. He used to do his work under a large tree, and either that tree of its descendant is still pointed out to tourists.

Hippocrates made his students take an oath that they would only work for the good of their patients and never give them any treatment which might harm them, or give away their secrets, and this oath is still held binding by many doctors today.

Many centuries followed, of quacks and witch-doctors, while just now and then a man of genius added something to real knowledge. One of those was William Harvey who, in the time of Charles II, showed that our blood circulates round the body, from the heart, through the arteries, and back again by the veins. Before that there was a vague idea that it just sagged about in the veins, while the arteries were actually supposed to carry air from the lungs – hence the name artery , or air tube.

But it still took another three hundred years for blood transfusion to become the commonplace life-saving thing it has become today.


The Milkmaid who helped medicine

Still nobody knew in the least what caused the plague cholera, smallpox, leprosy and all the other horrid things people died from. But there was a man, called Jenner, long before germs were discovered, who found out how to prevent smallpox. Actually, it was an unknown milkmaid that gave him the tip. She said to him one day that she could not catch smallpox, because she had previously had cowpox. This was a fairly mild disease, rather like chicken pox, which cows used to suffer from, and the milkmaids caught it from milking the cows. Jenner inquired and found it was a firm belief on the farms, that those who had cowpox could not get smallpox. So he experimented, and inoculated some volunteers with cowpox, exposed them to smallpox, and, true enough, they didn’t catch it. And that was how vaccination started, more than a hundred years ago, before it was discovered that smallpox is due to a virus.



If medical knowledge over all these centuries was in a primitive state what about surgery? The people who needed surgeons were the armies in the field, who had to have someone to care for their wounds. If you have read or seen Shakespeare’s Henry V, you will know a lot about that monarch’s campaign in France. He took 2,500 men-at-arms and 8,000 archers to France, and the medical stores for the whole lot of them were conveyed by one cart with two horses. If this seems incredible, it is still more strange that in the Peninsular War in 1808, much nearer our own time, the medical stores for Wellington’s army were conveyed in two carts drawn by bullocks. More soldiers in these campaigns died of disease than of wounds, but when they were wounded their prospects were grim. Amputations were done without any sort of anesthetic, and the great majority of the patients died.

So it was a very great marvel indeed when in December 1846, the first operation under an anesthetic was done in the UK, and the patient declared he had felt no pain and was quite willing to have it done again. This operation was under ether. Chloroform was introduced the following year, and surgeons were now able to operate when necessary without hurting their patients.

Marvelous as this was, it came very near to becoming a great disaster. Before anesthetics were invented, it was only possible to operate very quickly, and the best surgeon was the speediest one who didn’t go on hurting for more than a few seconds. But now all this changed, and surgeons began to tackle bigger operations and take longer over them. But remember they still didn’t know anything about germs and infection. While the speedy operations gave little time for germs to get in, so that many people recovered, the longer ones all got infected, and the poor patients mostly got blood poisoning.

Tragedy was prevented by the marvel of the introduction of antiseptics by Lord Lister. He had studied Pasteur’s work on gems, and Pasteur’s idea that they might be the cause of infection. He said, if all this blood-poisoning is being caused by germs getting into the operations, let’s kill them before they can get in. So he introduced a pump with a carbolic spray, which was kept working all the time he operated, and must have been very unpleasant for all concerned. But his patients all healed up and got well, without any blood poisoning. That was in 1887 and it really started something.

Birds and Reptiles

Birds and Reptiles

A bird soaring through the air seems to have very little in common with a lizard sunning itself on a rocky ledge. Yet the surprising fact is that present-day birds have evolved from reptiles. Millions of years ago in fact a creature existed which was to all intents and purposes both bird and reptile. Archaeologists quarrying in Bavaria discovered fossils of a small bird-like creature called archaeopteryx. Examination of these fossils showed that this long-extinct creature had the characters of both bird and reptile. It was clothed with feathers and could fly. It also had reptile-like characters. It had cold blood, possessed teeth and had the tail of a lizard.

Archaecopteryx, which became extinct many thousands of years ago, is evidence of the link between reptile and bird. There are other reasons which have enabled naturalists to establish their kinship beyond any doubt. But more surprising is it to see convincing proof of the relationship in a creature which is alive today.

A small living tree-inhabiting creature called ‘hoatzin’ which lives in South America is a living link between bird and reptile. When young, this curious bird clambers about on the lower branches like a four-footed animal, gripping them with its beak and feet and the clawed fingers on its wings.

The transition from reptile to bird probably took millions of years and was extremely gradual. There were undoubtedly a great many intermediate stages in the chain of development. Some naturalists believe that the reptiles, which often had to leap from the trees to the ground to elude their enemies, used their limbs so as to steady themselves in the air, and eventually developed scaly fins on their fore-limbs which made their downward flight a sort of parachute descent. As it learned to float and to soar through the air, the reptile gradually exchanged its arms for the feathered wings of a bird.

Little by little its other reptilian features disappeared. It is thought that the feathers of birds were derived from the scales of a reptile. The petrel, which has scales on its beak, seems to provide support for this belief.

Both reptiles and birds are hatched from eggs. Although the bird parents usually watch carefully over their eggs, while reptiles rely on the heat of the sun to hatch out their offspring, there is a great similarity in appearance between the eggs of birds and reptiles.

Great satisfaction and pleasure is derived by those who make a pastime of studying the habits of birds. This pursuit is one that can be followed by anyone who is prepared to employ a reasonably painstaking amount of observation. But those who are more ambitious and lucky enough to have a pair of field glasses, can add considerably to the range of their explorations. Many bird lovers use ‘hides’ – rough structures consisting of pieces of canvas laid over a wooden framework – for watching birds at close quarters.