From 'Adventures in Human Being'

In Gavin Francis’ book Adventures in Human Being, the author mentions the novel Zeno’s Conscience by the German-Italian writer Italo Svevo (1861-1928). In that novel, the main character, a hypochondriac businessman called Zeno, meets an old school friend. This friend is suffering from severe arthritis. Discussion moves to how, when walking briskly, each step might take less than a second and yet involve the action of no fewer than fifty-four muscles. Zeno finds this rather shocking and turns his attention inward, hoping to sense each one of those muscles in action. This does him little good. It does not give him a greater understanding of his body or sense of his being. In fact, it becomes counterproductive as walking becomes more difficult for him.

The story recognises how, in order to perform certain complex actions, it is not necessary for us to be consciously aware of every muscle contraction we make. Nor, for that matter, every muscle relaxation made. Most of our movements are done without careful thought or consideration. As I have typed this, I have been thinking about a number of different things, none of them being about which finger to put on what key or the order in which those actions must take place. (Witness the many typos I always need to correct.) Chameleons, an old professor once suggested, have their distinctive way of moving because, lacking a highly developed cerebellum, they need to move more deliberately. The cerebellum stores the information – some might call this a set of programmes – for all the movements we make. When we need to make a movement, we do not have to think much about it. We decide to move and subconsciously call upon the cerebellum’s involvement. In effect, the programme held there is run, and the movement is results.

What would it be like to be a chameleon? If my old professor was correct, it is doubtful whether I could think and type at the same time. I would have to think more carefully about every finger movement. This would surely detract from what I am thinking about. (It’s a good job I don’t chew gum!)

We tend to think of movement primarily in terms of muscle contraction. However, to make a movement, a whole repertoire of relaxations as well as contractions must take place in a highly coordinated way. A contraction may even be isometric in that it may occur without a change in length taking place. By becoming taut, that muscle provides a stabilising effect. There is much more to walking than Zeno was told, which is perhaps lucky for him.

Being smarter than 'phones

Biological knowledge must include understanding; it must be more than can be called up on a smartphone.

This note I made before the advent of AI. I am a great fan of AI. It can help us understand biology, especially if the responses given prompt us to ask better questions (aka prompts*).

* I wonder if, at least in some people's minds, the word 'question' will come to be replaced by the word 'prompt'.

Anatomical Junctions

The previous post had little, if anything, to do with the human body and more to do with South London's railways. So, here is a post about genuinely named anatomical junctions. I provide it by way of compensation and recompense for the previous post.

The following is a list of terms containing the word 'junction.' I have limited it to structures larger than cell size and provided a brief description for each:

• Atrioventricular Junction: The junction between the atria and ventricles of the heart, where the heart valves and conducting system are located.
• Costochondral Junction: The junction between the ribs and their costal cartilage, which allows for flexibility in the rib cage.
• Myotendinous Junction: The junction between a muscle and its tendon, where the force of muscle contraction is transmitted.
• Neurovascular Junction: The junction between nerves and blood vessels, often referring to points where nerves and vessels run close together.
• Oesophagogastric Junction: The junction between the oesophagus and the stomach, where the lining of the digestive tract changes.
• Rectosigmoid Junction: The junction between the rectum and the sigmoid colon, a transition point in the large intestine.
• Sacrococcygeal Junction: The junction between the sacrum and the coccyx, a slightly movable joint.
• Sternoclavicular Junction: The junction between the sternum (breastbone) and the clavicle (collarbone), a key joint for shoulder movement.
• Vesicourethral Junction: The junction between the bladder and the urethra, controlling the flow of urine.

I cannot vouch for how exhaustive this list may be. My online searches (including the use of AI) yielded just these. I do not remember the term 'junction' being used frequently. Indeed, only a few of those above (such as the costochondral junction and the rectosigmoid junction) were ever commonplace. Rather, the sacrococcygeal junction was more often referred to as the sacrococcygeal joint and the sternoclavicular junction as the sternoclavicular joint.

At every meeting of two veins, there is a junction. (Following the direction of blood flow, veins DO NOT branch.) Where named, a venous junction seems to reflect a need for clinical rather than anatomical precision. I was never taught a litany on named venous junctions.

Eponyms 2 - Poupart's Junction

I seem to be starting each month with something about eponyms. At least this time it gets a new number. That is because it is quite different from what has gone before when it comes to eponyms and to anything else for that matter.

Poupart’s ligament is not the only eponymous use of the name. Upon reading Richard Gordon’s Doctor in Love (1957) recently, I found this amusing story.

During a viva voce examination, Gordon is asked

“You are familiar with Poupart’s ligament?” asked the Professor, as we got on to hernias.
Of course, sir.”
“Ah! But where is Poupart’s junction?”
For a second I felt panic. This was an anatomical feature I’d never heard of.
“It’s the next station to Clapham Junction,” [the professor] said with a chuckle.

This geographical detail is indeed true—see the map below. However, I cannot vouch for the veracity of the rest of Doctor in Love (including whether this viva voce examination ever did take place).

FYI Poupart’s Junction is not named after the Poupart discussed in a previous post. It is named instead after the market gardener Samuel Poupart (b. 1807), who once owned a farm on land that is now part of the nearby Shaftesbury Park Estate. In particular, see the section on its history. (And if you really want to know more go here.)

[Source - https://upload.wikimedia.org/wikipedia/commons/1/1d/Clapham_Junction%2C_Stewarts_Lane%2C_Lavender_Hill_%26_Longhedge_RJD_17.jpg ]

‘POUPART’S JN.’ is written at an oblique angle, immediately to the left of the ‘LONGHEDGE’ that appears towards the middle of the map.

A quote about... JBS

Two famous physiologists of the nineteenth and twentieth centuries were J.B. Haldane (1860-1936) and his son J.B.S. Haldane (1892-1964)—the latter of whom was often known simply as JBS. Both were fascinating characters for a variety of reasons, and both made substantial contributions to physiology. As part of their investigations, they would often experiment on themselves and each other. This is a practice that today may not be deemed ethical—or wise—these days. I very much doubt that they filled in the appropriate forms or sought the approval of their relevant ethics committee.

Outside the laboratory, JBS had an attitude to teaching that mirrored his approach to his research. As Ronald Clark puts it in his JBS: The Life and Work of J.B.S. Haldane (New York: Coward-McCann, 1968)

'When it came to teaching, Haldane had his own ideas. He more than once said that the whole business of University education was to teach people to think; the corollary was that the more they were personally controlled in their studies, the less individual thinking they were likely to do. One outcome was that he often appeared unable to direct properly the work either of students or of his research colleagues.' (p94/5)

(Comment: To do this in some educational establishments today may require a bravery beyond that shown even by the Haldanes!)

Saccades

 I recently found the following among my old notes. It is from the book What Do You Think You Are? by Brian Clegg and appears in a section entitled The Double-Dealing Brain.

"In reality, the signals from the rods and cones in your eyes, funnelled through the optic nerves, are picked up by a series of modules that do things like separate out shapes, deal with blocks of colour and so on. This explains why what you see is deceptive. One obvious example is the fact that there's a blind spot on your retina where the optic nerve connects to it. But you don't see that gap - the brain fills the image in for you. Similarly, your eyes are regularly darting about in very quick little motions called saccades—but your brain irons out the motion-sickness-inducing jerkiness and provides a totally fake still image."

This particularly sparked my attention because of an experiment in which an old professor of mine took part. While visiting Moorfields Eye Hospital in London, he was persuaded to take part in an experiment that cancelled out the saccades to which Clegg refers. I don’t know exactly how this was performed; our professor did not say and probably did not know himself, except that an image at which he was looking was moved in such a way as to be opposite to his eye movements. The result was, for him, quite shocking. He could no longer see. It is not strictly correct to say that he went blind per se, but he did, in effect, lose his vision during the experiment.

Some students of podiatry that I used to teach had a similarly shocking experience—albeit at the other end of the body. As part of their training, they were required to administer anaesthetics to each other. This was under strict supervision, and what to expect was described clearly beforehand. One of the anaesthetics was meant to temporarily immobilise the leg. Despite knowing what to expect, on every occasion students would become quite distressed upon losing the use of one of their legs. Even those who had embarked on the process in a confident, even nonchalant, fashion quickly changed their demeanour.

Sight loss and loss of mobility are not uncommon and occur with increasing age. But they are usually gradual. They creep up on us sometimes without us really noticing. A sudden loss has quite a different bearing upon our lives, even though it may be something that may be envisaged, albeit in later life.

Addendum
Having written the above—and having gone to make a cup of tea—I am reminded, upon listening to the radio, that something else that may be sudden or gradual is the end of our lives. We die and are, to some extent, in the process of dying even while our bodies are able to resist the inevitable. If we do not reflect on that type of loss, maybe it is because we are subconsciously aware that we will not be here to notice the change.

Water 3

Having started to think about the place of water in human physical existence, the subject has grown. For example, a previous post—the second on the subject—was meant to be just a brief note, but it grew until it had numerous hyperlinks to other sources of information. This time I again hope to be brief. (Was I? See below.)

This time, I want to ask what appears to be a simple question, which I shall phrase in two ways:

    - Why is water tasteless?

    - Why does water have no apparent flavour?

Is flavour in the mouth or mind of the beholder? Yes, there are taste buds that respond to certain chemical constituents of food. Why no apparent response to water?

The chemicals to which the taste buds respond must be dissolved in water in order to reach the nerve endings the taste buds house. A dry is largely unable to taste anything.

Water does have a ‘mouthfeel’ that differs according to its temperature and a number of other factors.

Do we enjoy drinking water? We seem to enjoy it more when we are thirsty, i.e., when we need it more. When it is hot, we enjoy drinking cold water rather than hot water. Some people do enjoy drinking tepid or even hot water. That is not my preference. This begs the question, are there really preferences when it comes to drinking water? Sparkling (fizzy/carbonated) water—which does not occur naturally—has a distinctive mouthfeel, which many find particularly pleasant.

Why isn’t there a flavour that inclines us to drink more water? I was very much taken by a sentence in Helena Cronin’s book The Ant and the Peacock. She comments that ‘oranges taste sweet, not nutritious.’ From our desire for oranges based on their flavour, we indirectly obtain the nutrition they happen to contain—and indirectly water bearing the flavour.

Given that water is fundamental to life, obtaining it does not seem to be based on a desire for its enjoyment. Instead, a different mechanism is in play. We experience a need for it, a need that we call thirst. This need—or craving—must be satisfied. This need goes deeper than the pleasure to be had from experiencing flavour. It is better described as a dependency.