possible to identify such tumours by listening to the resulting echoes, but I have never managed such an impressive act. I suppose this is a case of constant ‘practice makes perfect’.
Despite this, my stethoscope is always a great aid, for listening not only to the heart, but also to the rest of the body. I grew up in Germany’s Harz Mountains, an area of the country that is very popular with motorcyclists in the summer. Serious accidents are common in the biking season and those horrific crashes often leave bikers with terrible injuries. On arriving at the scene of such an accident as part of an emergency medical team, I would begin by listening to the patient’s lungs and abdomen. I did this because it’s not uncommon to hear no sound of breathing on one side of the chest, even if the patient is still breathing.
The cause of this apparent contradiction is usually a collapsed lung (pneumothorax) on the side where no breathing sound can be heard, but it can also sometimes indicate an accumulation of blood in the chest cavity (haemothorax) or, in a worst-case scenario, a combination of both (haemopneumothorax). The sound made by tapping on the chest while listening through a stethoscope (doctors call this ‘percussion’) can allow a medic to distinguish between accumulated air and accumulated blood. An accumulation of air gives a sound reminiscent of beating on a drum, while an accumulation of fluid will dampen the sound, like striking a kettledrum filled with water. If the patient were able to sing and play the guitar along with all this percussion, they would almost be ready to take to the stage for a performance — if it weren’t for the fact that they were in need of urgent medical treatment.
During a routine medical examination, the doctor will often listen to the abdomen using a stethoscope, to check the function of the intestines. After a motorbike accident, the medic will ‘percuss’ the abdomen to identify whether there is any internal bleeding or accumulation of fluids. As you can see, the stethoscope is a constant and valuable companion of medical practitioners; it is indispensable in many areas of treatment, but especially that of the heart.
However, like everything else, it has its limits. There are specialist cardiology stethoscopes with which you can almost hear the worms moving beneath the soil, but even they do not allow doctors to perceive everything — for example, the third and fourth heart sounds. For that, a special ultrasound examination of the heart is necessary (called an echocardiogram). It allows doctors to check the size of the heart, its atria and ventricles, the thickness of its walls, its overall mobility, its valves, and any defective blood flows. Often, a doctor will also be able to monitor for pathological changes to a patient’s heart, including defects in the valves or constrictions in the coronary blood vessels.
While I was a medical student, I learned a mnemonic that has stayed with me ever since: ‘All Physicians Take Money at 22.45’. I’m sure all physicians are willing to take money at other times of the day, but what does this have to do with the heart? Well, this mnemonic helps young medics remember where to place their stethoscope when listening to the function of the heart valves.
Having memorised this little sentence, all a doctor has to remember is that the listening points are described from top right to bottom left. The time 22.45 describes the intercostal spaces (between the ribs), and the initial letters of the words in the sentence are the same as those of the names of the valves (Aortic, Pulmonic, Tricuspid, and Mitral). Once you know this, you can listen very precisely to your own heart-valve sounds and any possible murmurs. However, interpreting these sounds is a complicated business and should be left to an experienced cardiologist, since recognising the subtle differences and changes is almost impossible without decades of practice.
There is a six-level scale for grading the loudness of heart sounds, ranging from ‘difficult to hear even by expert listeners’ via ‘readily audible but with no palpable thrill’ (medical word for tremor or vibration) to ‘loudest intensity, audible even with the stethoscope raised above the chest’. In addition, doctors distinguish between different ways the sounds change over time, using criteria like crescendo or decrescendo, i.e. getting louder or getting softer; or diamond-shaped, which means getting louder then softer again; or a constant, unchanging intensity. The heart is an instrument that can play many kinds of music. Doctors use these distinctive features as the basis for diagnosing problems with the valves of the heart, and prescribing the best treatment.
All Physicians Take Money at 22.45 — the stethoscope listening points
The way all the components of the heart work together is complex, but also absolutely fascinating. However, even the greatest, most powerful engine is useless if there are no roads for the vehicle to drive on. Our blood vessels are precisely those ‘roads’, without which our heart, as the central pump, would have no meaning. In the end, the heart’s strength and stamina, as well as its intricate valve construction and conduction system, all serve one single purpose: to send our blood rushing at full throttle along those roads.
The Body’s Highway System
Our blood vessels transport blood and nutrients to the farthest reaches of our body. In fact, there are only a very few areas that are not permeated by them. Those include the corneas of our eyes, the enamel of our teeth, our hair, our fingernails, and the outermost layer of our skin. To transport all that blood, our body needs a proper system of pipes and ducts: our blood vessels. They are also the highway system of our bodies. With the difference, however, that taken together, our arteries, veins, and capillaries (the finest branches of our blood vessels within tissues), are more than ten times longer than Germany’s famous autobahn system — totalling around 150,000 kilometres (over 93,205 miles).
Unlike the pipes that form the sewerage systems beneath our cities, blood vessels are very elastic. This is a good thing, because it allows the body to regulate the diameter of the blood vessels. It’s what enables the body to provide certain organs and structures with a greater or lesser supply of blood according to whether they require more or fewer nutrients and oxygen molecules at any given time. When it comes down to it, this is no different to the engine of a car: the more you step on the accelerator, the more fuel is injected into the motor’s cylinders.
When we are out jogging, our muscles need a better supply of blood to satisfy the increased need for oxygen. At the same time, our skin also receives more blood, so that it can release some of the increased heat into the environment via the cool, sweat-moistened surface of the skin. To make this increase in blood supply happen, our body reduces the amount of blood it provides to other parts of the body — for example, the gut. After all, digestion can always wait till later. A similar thing happens in our lungs: if a section of the lung registers a reduced oxygen supply, the vessels in that section will constrict. There is no point in sending blood to pick up oxygen where there is none to be had.
All this is possible because our arteries and veins have an elastic structure. The two types of blood vessel are similar, but there are certain differences between them. All have walls consisting of three layers, with the innermost layer made up of supporting connective tissue and what doctors call the endothelium. The endothelial cells line the inside of our blood vessels, serving as a barrier to protect the tissue of the vessel wall, and they can play an active part in the regulation of the cardiovascular system. They are the interior decoration and the Anaglypta of our blood vessels, but they are also much more than that. For instance, they can release nitric oxide, which acts as a signal to the vessels surrounding the heart and those of the skeletal muscles to relax, allowing them to dilate. This happens during physical exercise and other times of exertion to supply more oxygen-rich blood to the muscles as they work.
Structure of a blood vessel wall
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