Cells typically stay separate

Cells are often described as the smallest unit of life. That applies to both uni- and multicellular organisms. This is a characteristic they maintain as long as they survive. As such, they possess an ‘individuality’.

To the benefit of the organism as a whole, some cells divide while others, also to the benefit of the organism, do not. Still others may usefully disintegrate - as in the case of megakaryocytes which give rise to platelets important in blood clotting.

Obvious - yet rarely stated - is the fact that cells do not typically merge with other cells. Here, the fusion of sperm and ova is seen as a special case. Each contains only 23 chromosomes and so only half of the entire genetic material. Thus, sperm and ova are - in a sense - only half cells. (Indeed, whether sperm qualify for the title ‘cell’ is a moot point.)

With very few exceptions, cells remain separate from each other throughout their lifespan. They do not blend or merge to form mega-cells. Those cells that do fuse do not fuse with cells of another type. They fuse only with cells of the same type. In so doing they become multinucleated. The cytoplasm is combined but not the nuclei. In this, a hint of the ‘individuality’ I mentioned above, persists.

What does having two nuclei within the same cytoplasm imply? In practical terms, there is an increase in the efficiency of the cell. (If by cell we mean that bounded by the cell membrane.) It implies double input/output and information processing capacity.

Those cells in our bodies that do undergo fusion do so in specialized circumstances, such as during development and tissue repair. For example:

1. Muscle Cells: Muscle cells, known as myocytes, can fuse to form multinucleated muscle fibres. This process contributes to the growth and repair of skeletal muscle tissue.
2. Osteoclasts: Osteoclasts, which are responsible for bone resorption, are formed by the fusion of monocyte/macrophage precursor cells.
3. Syncytiotrophoblasts: In the placenta, syncytiotrophoblasts are formed by the fusion of cytotrophoblasts. These multinucleated cells play a crucial role in facilitating nutrient and gas exchange between the maternal and fetal circulations.

Cell fusion is not a random process. It is tightly regulated and involves complex molecular mechanisms. This implies that cell fusion is a process that has evolved. As such, it offers the organism a biological - that is, a survival and/or reproductive - benefit. To use a word rarely used biologically, it is ‘deliberate’.

Having introduced this word, I will stop here and ponder what, in a biological context, ‘deliberate’ means and how it might be used.

Deconstruction

I originally entitled this blog - ‘Deconstructing Humpty’. (I still apply the phrase in private to the wider project upon which I am working.) The word deconstruction is most commonly associated with the French philosopher Jacques Derrida (1930-2004). What did he mean by this term?

Derrida introduced the concept of deconstruction to refer to a method of critical analysis primarily applied to texts and discourse. At its core, deconstruction challenges traditional notions of binary oppositions and hierarchies by exposing the inherent complexities, contradictions, and ambiguities within them. It involves unravelling the layers of meaning in a text to reveal the underlying assumptions and biases, often highlighting the presence of marginalized voices or alternative interpretations.

Deconstruction does not seek to dismantle or destroy meaning but rather to explore the multiple interpretations and possibilities that exist within a text. It emphasizes the fluidity and instability of language, suggesting that meanings are not fixed but are constantly shifting and evolving based on context and perspective.

Derrida argued that language is inherently unstable, and attempts to fix meaning ultimately lead to exclusion and marginalization. Therefore, deconstruction aims to disrupt the binary oppositions that structure thought and language, opening up new ways of understanding and engaging with texts and ideas. It encourages readers to interrogate texts and discourse to uncover hidden assumptions and explore alternative interpretations.

This is something I am exploring applied to human bodies and our being physical entities. Borrowing some of Derrida’s ideas gives a different perspective on how the human body is understood.

An alternative title I often bandy with is 'Reconstructing Humpty'. I shall begin to describe what this means at a later date. (I say 'begin' because it is an ongoing process.)

Continental Philosophy

Philosophy is often frowned upon by scientists. They see themselves as engaged in unravelling the mysteries of nature by doing laborious practical work while philosophers do their work from the comfort of an armchair. The type of philosophers that those in English-speaking countries criticise are referred to as analytic philosophers. They are the type of philosopher with which they are most familiar.

Analytic philosophy is a philosophical tradition that emphasises clarity of language, logical rigour, and precise analysis of concepts. It emerged in the early 20th century mainly in the English-speaking world. Analytic philosophers typically focus on breaking down philosophical problems into manageable components. Problems are solved using techniques such as formal logic, linguistic analysis and the scrutiny of ordinary language.

Thus, analytic philosophy shares much in common with science. However, it is not the only form of philosophy practised. Continental philosophy is a branch of philosophy that originated in continental Europe, especially in the 19th and 20th centuries. Characteristically, it emphasises human experience, culture, and society. It explores concepts like existentialism, phenomenology, hermeneutics, and structuralism. It is more personalised than analytic philosophy or science.

A criticism of those sciences applied to human beings is their lack of personalisation. The object studied is the human body devoid of a personality - or a soul. Science borrows more from analytic philosophy than it does from continental philosophy. In its inclusion of human experience, continental philosophy may have something to offer a science of the whole human being - the whole person.

Physicalism (Materialism)

Physicalism - sometimes referred to as materialism - is a philosophical perspective that asserts that everything in existence is ultimately physical by nature. Thus everything that exists can ultimately be reduced to physical entities or processes and can be explained in those terms. As such, this view denies the existence of anything non-physical or supernatural. It follows that only physical things can be studied and understood within the framework of the natural sciences. Also implied is that all phenomena - including mental states and consciousness - can be understood purely in physical terms. (Remembering that biochemistry can be reduced to physics.)

As a worldview, physicalism emerged in response to the problems arising from dualism. Dualism proposes the existence of two fundamentally distinct substances: the physical and the non-physical. The latter is often associated with the mind or soul. (Substance being used here in a philosophical rather than scientific sense.) Physicalism takes its fundamental stance from denying that the mind or soul exists apart from a body with live physical processes.

Physicalism has difficulties of its own. One of the key debates within physicalism concerns the nature of mind and consciousness. Critics of physicalism often raise doubts about its ability to account fully for phenomena like consciousness and subjective experience. Within physicalism, there are shades of opinion in response. Some physicalists argue that consciousness can be explained fully by neurobiological processes in the brain. Others treat mental phenomena as something distinct proposing a separate approach - albeit within the tenets of physicalism.

Biological science avoids these problems by either being unaware of them or actively ignoring them. However, it would be beneficial for biologists to be aware of the thought around physicalism. Biology is an essentially materialistic science.

The biologist and the things biologists study belong to the same realm: that of living things. However, the two are kept very separate. The biological characteristics of the biologist are never allowed to inform the object of study - or vice versa.

This is typically explained as keeping subjective experience out of objective observation. But has anybody tried to find a middle ground? Has anybody tried to develop a way of embracing the subjective to the benefit of the objective? I am unaware of any concerted attempts to do so. If there are any, I am sure they will have been kept to the periphery of biological science as it is typically practised.

Motto #1

When teaching, I had a favourite image with which I began my classes on human anatomy and physiology. This I shared in my post ‘OHT1’. I also had a question I asked the students to keep asking themselves throughout the course. It was:

What does this structure or process confer on me?

This, I think of as ‘Motto #1’.

Rather than simply learning about the structures of the human body and what they do, I wanted my students to see what they were learning as being about their bodies. Each of the things we considered had a direct bearing on their lives.

When studying the human body it is easy to adopt an academically detached position disconnecting oneself from the object in question. Here that object is what each of us in the classroom was - a living human being. So, when I spoke of hearts and lungs everybody in the room had these organs actively keeping them alive. (Not least the girl who had had a heart-lung transplant.)

We all live by leaving behind

An interesting quotation from Jorge Luis Borges (1899-1986) is ‘We all live by leaving behind.’ This may be found in his short story Funes the Memorious.

This is a somewhat poetic phrase; it may be understood in numerous ways and will mean different things to different people at different times.

From my perspective - from my way of studying the human body - it brings to mind how we are made of transient material. Stuff that we take and then excrete - leave behind. We are made of atoms and molecules borrowed from the world around us for a limited time. We continually replace them with a complete turnover taking an estimated seven to ten years.

Thus, our physical lives may be characterised as a constant ‘throughput’ of material while somehow we remain the same person.

A Rule of Three

 Anatomy has a lot in common with geography. The phrase ‘topographical anatomy’ is sometimes used to refer to the study of the location of different body structures. Whether ‘study’ is the correct word is a moot point. Learning where everything is situated is not so much ‘study’ as ‘memorisation’. A lot of anatomical study involves rote learning. This is onerous, tedious, and [add your own derogatory term(s) here if you find this process irksome]. It is not learning in the true sense. It is 'cramming' for an exam.

Aides to learning (and memorising) are to be welcomed. There are many mnemonics one may use. (Some of them are clean! The clean mnemonic for the 12 pairs of cranial nerves I do not remember, but the more risqué one I had memorised on only the second hearing!)

There is a more thoughtful approach. Where possible, look for anatomical principles. Look out for commonalities and patterns.

The first of these is ‘the rule of three’. Anatomical structures do not consist of a single cell type. They are typically made of layers of cells and extracellular material. These layers are often continuous with each other and are hard to differentiate. Sharp distinctions between layers are not always obvious. However, that has not stopped anatomists from giving them specific names.

As a rule of thumb, start with the assumption that there are three named layers. Look out for these and memorise them that way. What applies to one structure often applies to another. Once a principle has been learned, it is applicable elsewhere. Sometimes the same or a similar word is used.

Helpfully, the outermost layer of a structure is usually a connective tissue capsule that envelops an organ or loose connective tissue that forms a kind of ‘packing’ (such as around blood vessels). If there should be more than three named layers, it is often because a ‘parent’ layer has been subdivided. Usually, this is the middle or inner layer. Realising this helps.

A question arises.

Is the ‘rule of three’ a genuine anatomical arrangement, or is it a reflection of the mentality of the anatomists who originally named these layers? That is something else to consider. Being unconvinced about what we have to learn helps us remember it!

Newton saw seven colours in the rainbow. (From which we get the mnemonic Richard Of York Gave Battle In Vain.) But the seven-colour idea was more in keeping with a Renaissance tradition than observation. Did he really see seven colours? And do we when we see a rainbow or light shone through a prism? Or are we simply following what we have been taught?