The Royal Institution Christmas Lectures
Heinz Wolff: Signals From the Interior
In his 1975 CHRISTMAS LECTURES, Heinz Wolff explores how to investigate your inside without breaking the skin. Each lecture will take a particular set of signals, consider their origin and why they are important, demonstrate how they are detected and measured, and explain how the instrumentation works. The lectures will also illustrate how much modern medicine is becoming dependent on a proper application and understanding of engineering and physical principles.
Where to Watch The Royal Institution Christmas Lectures • Heinz Wolff: Signals From the Interior
6 Episodes
- You as an EngineE1
You as an EngineThe body can be regarded as a rather special internal combustion engine, insofar as its ability to perform mechanical work is concerned. Some of this work is expended to keep it alive, for instance by pumping the blood round and breathing, whilst the rest appears as external activity. Walking, running and lifting sacks of coal all involve the expenditure of energy which ultimately has to be derived from the fuel, i.e. the food supplied to the body. Just as in a car engine, not all the energy contained in food can be converted into mechanical work; at best only about 20% appears as work, the rest being converted into heat. - Pumps, Pipes and FlowsE2
Pumps, Pipes and FlowsThe heart was at one time thought to be the very seat of life and personality, and indeed we still speak of black hearted villains and soft hearted aunts. This was so presumably because the most obvious immediate sign of death was cessation of the heart beat. We now know that the heart is just a blood pump, or more correctly a pair of pumps, which are responsible for keeping the major transport system of the body in continuous motion. This knowledge has not decreased the importance of the heart because at normal body temperature we cannot survive a cardiac arrest of more than a few minutes. - Spikes and WavesE3
Spikes and WavesIt is one of the properties of muscle and nerve cells that their activity is accompanied by electrical events which can be detected outside the cells. An extreme manifestation of this effect is found in electric fish where special cells similar to muscle cells are connected in series like a multi-cell battery to produce external voltages sufficient to stun other fish. - Probes, Sondes and SoundsE4
Probes, Sondes and SoundsIf one had to associate a particular instrument with doctors in general, it would certainly be the stethoscope. It enables him with convenience and decorum to listen to the noises inside his patient. Most of the interesting noises occur in the chest and in particular in or close to the heart, though bowel sounds have also received some attention. The interpretation of the sounds takes experience, but this can be supplemented by detecting the sounds electronically and displaying them as a picture, when it also becomes possible to measure the time relationship between them. - Looking Through Your SkinE5
Looking Through Your SkinTo be asked to diagnose a fault inside such a complex system as the human body without being able to look inside it would appear to make the task very difficult, yet this is a problem doctors had to face until the advent of X-rays at the turn of the century. Tissue and bone, except in very thin layers, are opaque to visible light; we cannot therefore look through or into the body in the ordinary sense at all. Other forms of electromagnetic radiation can penetrate tissue and bone to varying degrees, and with their aid avisible image can be reconstructed. - Signals From the MindE6
Signals From the MindIt is part of everyday social experience that we receive and send out signals indicative of our emotional or mental state. 'He looked happy' ... 'she sounded rather anxious' ... 'he parted with a confident handshake' ... 'there was the smell of fear about' ..., are all phrases which we use without really thinking about the nature of the signals involved. Most of the code, irrespective of the sense through which the message is received, almost certainly has to be learned.