Ralph W. Gerard and ‘Body Functions’ (1)

In a previous post, I referred to a quotation from Ralph W. Gerard (1900-1974). This prompted me to look at his other writing. The title of one book that particularly caught my eye was Body Functions (1941). (It was subtitled simply ‘Physiology’ as if body functions and physiology were in some way synonymous.) I am rather sensitive to the use of the word ‘function’. I once had to teach a course entitled ‘Human Function’. That was not a phrase of my own devising. It was meant to be a course on human anatomy.

I was once invited to a planning meeting in Heidelberg by a German philosopher friend. The aim was to put together a funding application for the study of the philosophical understanding of function from a biological perspective. The late American philosopher Karen Neander who did much work in this area was invited as a speaker. At that meeting I became acutely aware of the implications and problems that surround the word ‘function’—especially for philosophers. Frequently, the word implies something deliberate and purposive. In nature, there are no such things. There is no guiding or directing force; what happens does not happen for a specific purpose or with a particular aim. Whatever the personal religious beliefs of the scientist, any role for a deity offering a guiding hand is excluded. The scientific approach holds that everything can be explained by what there is; no external factors or entities are necessary. (As such science is inherently materialistic—although the conceptual framework offered by physicalism is preferred nowadays.)

The language we use to convey science must adhere carefully to the ethos of being unguided and undirected. Using words like ‘function’, with its purposeful connotations, can be misleading and must be avoided. To talk of the function of the heart is wrong. It does pump blood but it was never designed or meant for that specific purpose. It simply does something that contributes to the organism’s survival.

Lizard walking

One of the realisations one makes when continuing to study a subject beyond one’s initial formal education is that things you were once told in all honesty are sometimes not quite right. There are many reasons for this although one thing is sure. No teacher or lecturer ever deliberately provides their students with false information. (Or if they do, it is to make a point that is immediately made clear.)

When it comes to models of the atom, the situation is perhaps a little greyer. I was taught the Bohr model of the atom at school—although it was not given that name. It was ‘the atom’. When I went to university we were taught something quite different. The flaw in what I was taught at school was not some much the inaccuracies as the fact that we were not told that it was only a model. We thought that it was what the atom was really like.

As a model, the Bohr model serves many useful purposes—but not as a description of what the structure atom is really like. What we were taught at university was also a model—albeit a better one—but a model nonetheless.

As undergraduates, when studying the nervous control of movement, we were told by an old professor that reptile movement was slower and deliberate because they had to ‘think’ about each movement. That is because their cerebella are much simpler than that in higher animals. The input the reptile cerebellum makes to locomotion is limited. The missing input had to come from elsewhere. That was from the brain, which had to divert what it was doing to ‘thinking’ about locomotion.

This description is not wrong but not a complete description.

Firstly, it overlooks the fact that reptiles are ectothermic animals and have a particular way of life. Indeed, when sufficiently warm, ectotherms can move quite quickly. They demonstrate a ‘sprint-and-pause’ style of movement which is, in fact, a highly efficient way for them to conserve energy. Furthermore, that plays a key part of their survival and hunting strategies.

Secondly, and very easily overlooked, is how in animals with side-to-side movement, walking and breathing at the same time is difficult. There is a need to stop every so often in order to breath. This is now known as Carrier's constraint after the American biologist David R. Carrier.

And about which a limerick has been penned by the English paleontologist Richard Cowen.

The reptilian idea of fun
Is to bask all day in the sun.
A physiological barrier,
Discovered by Carrier,
Says they can't breathe, if they run.

The realisation that walking and breathing at the same time was difficult for animals with side-to-side movement, only came to prominence in the late 1980s, after my old professor has retired. So he could not have known about it. However, when discussing organisms, it must be remembered that many different factors are in play at the same time. To do otherwise is, in a quite literal sense, not organismal thinking.

And there is always the caveat that something we haven’t thought of (yet) might apply too.

What does pass through the spermatic cord?

When I was an undergraduate, our anatomy teacher became quite irate with us after one test because of the particularly poor answers that she got in response to one question in particular. That question asked…

‘What passes through the spermatic cord?’

The spermatic cord is a bilateral structure related to the testes and therefore found in the lower abdomen of males only. It is so called because of its cord-like structure and appearance. In many respects it is an extension of the abdominal cavity. Each testicle develops high up in the trunk of the embryo and migrates into the scrotum. As it descends, it carries with it the vas deferens and related nerves and vessels, to put it simply. (See below.)

It appears that none of us gave a satisfactory answer to the test question—and that includes me. Furthermore, I remember being stumped when I first read the question. I had an inkling but not a complete or satisfactory answer. I also remember thinking—when our teacher told us what she had expected as an answer—how poor my attempt had been.

I remember this anecdote because of one particularly amusing comment. With a rather steely look and in a very scathing tone, our teacher told us, ‘The answer is not sperm!’ (That answer had been given by somebody and was tantamount to saying somewhat wryly, ‘I don’t know.’) This caused a general chuckle to go around the room, causing our teacher to pick on various smirking individuals and to castigate each in turn for the poor answers they had given—poor answers that she obviously found quite memorable.

So what does pass through the spermatic cord?

So as to try not to miss anything (this time), here is the result of a careful search in tabular form:

Structures within the spermatic cord:

• Vas deferens (Ductus Deferens): A tube that carries sperm from the epididymis to the ejaculatory duct.
• Arteries:
  • Testicular artery: Supplies blood to the testicle.
  • Artery of the vas deferens: A branch artery supplying the vas deferens.
  • Cremasteric artery: Supplies blood to the cremaster muscle.
• Veins:
  • Pampiniform plexus: A network of veins that surrounds the testicular artery to help regulate testicular temperature.
  • Vein of the vas deferens: Drains blood from the vas deferens.
  • Cremasteric vein: Drains blood from the cremaster muscle.
• Nerves:
  • Genital branch of the genitofemoral nerve: Innervates the cremaster muscle.
  • Sympathetic and parasympathetic nerves: Autonomic nerves that travel with the arteries to the testicles.
• Lymphatics:
  • Vessels that drain lymphatic fluid from the testes to the abdominal lymph nodes.
• Coverings of the spermatic cord:
  • Internal spermatic fascia: Derived from the transversalis fascia.
  • Cremasteric muscle and fascia: Derived from the internal oblique muscle.
  • External spermatic fascia: Derived from the external oblique aponeurosis.

To which may be added (and I don’t think we were taught this):

• Remnants of the processus vaginalis: A potential remnant of an embryonic structure may be found within the cord.

Note:
To avoid confusion, I need to point out that although there is a cremasteric artery and vein within the spermatic cord, the cremaster muscle per se is a muscular layer surrounding the spermatic cord and testes—and so not passing through the spermatic cord. It is the contraction and relaxation of this that regulates testicular temperature.

A way of thinking

Glucose plays a vital role in providing biochemical energy. We are familiar with its chemical formula C6H12O6 and may even be familiar with diagrammatic representations of its ring-like molecular structure. We may also be aware of the ratio of its atoms C:H:O being 1:2:1. In particular, the ratio of hydrogen (H) to oxygen (O) is 2:1 and that, of course, is the same as in water. Not everybody notices this until told, and then there is something of a ‘eureka’ moment. Thus, another way of thinking about the glucose molecule that is also not immediately obvious is thinking of it as 6 carbon atoms and 6 water molecules. Indeed, the chemical formula for all of the simple sugars is (CH2O)n (where n is a number greater than or equal to 3). Put simply, each sugar is a carbon atom and a water molecule n times over, depending on the sugar in question.

This in turn takes us back to where sugar comes from: plants and photosynthesis. Here in very simple terms, a molecule containing one carbon atom (carbon dioxide) and a water molecule are turned into glucose—with some oxygen left over and released into the atmosphere for us to breathe.

Embryonic problem-solving

As taught, embryology often seems a lot less dynamic than might be expected. After all, it deals with something going through rapid change. Something recognisably human is formed from a single cell in only a matter of weeks. A lot of embryology is primarily focused on how organs attain their final form. This may be better described as ‘organogenesis’. What of the intermediate or transitional forms that organs take before attaining their final forms? What is going on at a fundamental level?

Embryology can be considered as organismal problem-solving. For example, initially the embryo is formed of a ball of cells—a morula. This reaches a limiting size when it can no longer rely on the passive diffusion of nutrients, respiratory gases and waste products in and out of this simple ball. The cell mass then forms itself into a hollow ball called a blastula. As this enlarges, something different is needed to allow development to continue. Thus, the hollow ball folds in on itself to form a gastrula.

What I have been describing (albeit rather simplistically) is a series of problem-solving steps. At each transition noted above, a problem is being solved. Embryology is not just the formation of an organism as an object; it is the production of a problem-solving entity. The constant problem any embryo needs to solve is how to survive. It does this in different ways at different times depending on what it happens to be like at that time.

Know thyself - differently

The Harvard geneticist and Nobel laureate Walter Gilbert (b. 1932) described the Human Genome Project as "the ultimate answer to the commandment 'know thyself'." If so, what was it about our-selves that we have learnt?

What does a sequential knowledge of base pairs say about selves?

And…
What did we expect to learn but didn’t?
What did we think we could learn but found that we couldn’t? (And maybe can’t.)

And what did we say that we would learn, knowing that we won’t, just to make sure it got funded?

Darwin’s gaze

According to a former colleague of mine, Charles Darwin's gardener was bemused by how Darwin would stop and ponder so long over things he found in his garden. My colleague never gave chapter and verse. It was perhaps too good an anecdote to need one; it was exemplary of the man even if not entirely accurate. Now with AI, I have been able to find out more. The reference seems to be to Joseph Parslow (1812-1898), who worked as Charles Darwin's butler and gardener for many years. He often observed Darwin's intense focus on the natural world. What Parslow related was, "When he was at work in the garden, he would often be seen to stop in front of a flower, or a tree, and stand for a long time, sometimes with his hands behind his back, sometimes with his head bent forward, quite motionless, as if in a trance, absorbed in deep thought." This sentiment is often paraphrased and widely reported, including by Darwin’s family and by other members of his staff. This encapsulates Darwin's meticulous observation and profound contemplation of nature, which was a hallmark of his scientific process. He was not idly looking at flowers—as most do; he was examining them with an intense, scientific curiosity. In so doing, Darwin was responsible for changing our whole worldview, including our view of ourselves.