First Steps in Anatomy and Physiology

When studying the human body, the first steps taken by most students have a lot in common. It does not matter if one is aiming for a professional qualification or whether one is studying the human body out of mere interest. When anatomy and physiology are combined, this is particularly so. Anatomy and physiology are two separate sciences with very different histories. However, for teaching students not studying medicine, they are often combined into a single unit of study. That there are textbooks combining the two sciences illustrates this. There is a lucrative market for such books. Courses in life and health sciences are very numerous. Thus, publishers vie for market share. As a result, the textbooks available have settled on a similar layout and style. Any textbook that bucks the trend will not appeal to a mass market and will not be as commercially successful. As a result, textbooks have converged on a similar approach.

The three overhead projector transparencies (OHTs) mentioned in previous posts represent three common themes in these textbooks. All these textbooks open with an introductory chapter with a title such as Orientation. It is unnecessary to describe in detail here the content of that chapter. Instead, it is important to note how the conceptual framework for the rest of the book gets laid down in this chapter. The Orientation chapter introduces the ideas behind each of the OHTs I mentioned elsewhere.

OHT-1

OHT-1 depicts how the body is divisible into different levels of organisation. The image in the earlier post is interpretable in two ways.

(i) Organisms consist of organs. Organs consist of tissues. Tissues consist of cells. Cells consist of chemical molecules.

Alternatively, one can go in the opposite direction.

(ii) Chemical molecules form cells. Cells form tissues. Tissues form organs. Organs form organisms.

Usually - as in my OHT-1 - a directional arrow is given. However, one may go in either direction. Although a viable option, thinking simultaneously in both directions is not suggested.

The above provides the conceptual framework within which the reader begins to think. Different textbooks offer different versions of what I refer to as OHT-1. In due course, I will post some I have collected over the years.

OHT-1 is a very simplified and incomplete portrayal of what the body is really like. That should be obvious. However, that incompleteness goes uncommented upon and unexplored.

OHT-2

OHT-2 depicts the different physiological systems into which the body is divisible. It would be more accurate to say that it represents how the author or editor of the textbook chooses to divide the body. There are often subtle differences in the naming and sequencing of different body systems. For example, the muscles and bones may be presented as two distinct systems or as a single musculoskeletal system. Again, this provides the conceptual framework within which the reader begins to think.

In the rest of the textbook, each system gets a separate chapter. Details of each system's structures and processes follow. These begin at the organ level and proceed into finer and finer detail.

There is never a chapter at the end of these textbooks that puts everything back together again. (That, in effect, is the Humpty Dumpty Problem.) The physiological systems remain as separate systems. There is never a conceptualising of what the structures and processes mean to the life of the person studying the subject. After all, what they are studying is what they are.

I used to ask students to have in mind this question at all times:

What does this structure or process confirm on me?

Focusing that question on the individual student (the 'me' in the question) was meant to make the subject more pertinent and less abstract.

OHT-3

OHT-3 represents the concept of homeostasis. Homeostasis colours the intellectual framework for understanding much of physiology. As stated in another post, I avoided talking about homeostasis except to say why I was avoiding it. While it is a concept very much ingrained in biological thought, it is not without its critics. That should be acknowledged. However, that is rarely the case. Neither should it be accepted uncritically. That is often the case. The typical description of homeostasis is an uncritical statement of orthodoxy - a statement of a belief held by biologists. Furthermore, it is a belief frequently misunderstood and misrepresented.

Sara Tells My Stories

Following a lecture I had just given, an undergraduate student approached me and asked if I had taught a girl called Sara some years before. I replied that I had. I remembered her very well. "I thought so," the student said. "She tells the same stories that you do."

Before coming to university, this student had attended a preparatory course elsewhere; Sara had been one of her lecturers. The anecdotes she was now using to illustrate her teaching were ones I had used for mine. I did not mind that my stories were being (re-)told by somebody else. Instead, I was delighted. Something about my teaching was proving useful!

There are plenty of textbooks to consult for the facts and figures one needs to teach a course. However, they do not contain anecdotes. Those I had told had stuck in Sara's mind. Anecdotes provide embellishments not found elsewhere. They serve as aides-memoirs. They never appear in isolation. They are always used to illustrate course content. They are hooks upon which the much drier facts and figures hang and come to life. They serve to make what is dull more vivid.

(I think, that makes this anecdote an anecdote about anecdotes.)

The ‘Non-OHT3’

I briefly mentioned an overhead transparency I nicknamed OHT1 in an earlier post. I also mentioned how, although there was no official OHT2, there was an image I would have used. Both of these I shall be dwelling on in greater detail in future. Here, I point out a third transparency that was deliberately absent. Thus, I call it the ‘Non-OHT3’. There is, of course, no accompanying image. This absent transparency represents how the idea of homeostasis (sometimes spelt homoeostasis) was deliberately missing from my teaching.

That may seem strange. High school pupils studying biology learn about homeostasis. As described there, it is something essential for life. It is a vital characteristic possessed by organisms such as ourselves. Definitions of homeostasis describe the body maintaining a stable internal state despite external changes. The word ‘balance’ is often applied - I suggest somewhat indiscriminately. It remains a popular notion even in higher education. I know of physiology books written based on the principle of homeostasis. I contend that that is because it is a notion expounded uncritically. It makes sense until analysed carefully.

I deliberately avoided discussing homeostasis except to urge caution when reading about it. It gives the impression of a somewhat passive body. Instead, the body is highly active. Those who have looked at homeostasis carefully have raised doubts about its voracity. Accordingly, they have proposed alternative dynamic alternatives.

I shall return to these in due course.

A Strange Place for Taste Buds?

One of the first anecdotes I heard as an undergraduate was about taste buds being present around the anus. Since it was mentioned briefly in a lecture, there was no opportunity to discuss it further. Who made the discovery was not mentioned. I subsequently tried to find out more. As a postgraduate student, I mentioned it to a couple of colleagues. One said that he had also heard this but knew nothing more. Another wondered whether it might be salivary glands rather than taste buds. The salivary gland idea makes sense. Salivary glands would lubricate the anus, easing the passage of the faeces.

We are used to the idea of tasting food as it goes in. Apart from enjoying certain flavours, disliking others is particularly important. What tastes unpleasant is often also harmful. Such food is best spat out. Tasting spent food on the way out seems odd - if not pointless.

I recently discovered an article in New Scientist (Jan 27th 2024. No 3475) called Why are there taste receptors on our testicles? (What we used to call taste buds were referred to as taste receptors.) The article pointed out that taste receptors are present in the guts of rats. That is a finding made in the 1990s. Subsequent work found them in our guts also. Finding this spread of taste receptors - between mouth and anus - is not necessarily strange. All the parts mentioned so far belong to the gastrointestinal tract. Perhaps genes responsible for their formation are expressed randomly throughout. However, taste receptors are now known to be present in other organs and tissues not part of the gastrointestinal tract. They are present in the heart, brain, bladder, lungs, body fat and, as the article’s title implied, the testicles.

Our choice of words may be causing problems. I still use the old taste bud terminology. Using the term taste receptor may be no better. We associate taste with our mouths. It is a mental construct. It is something in our consciousness - a product of the mind/brain. They are neither taste buds nor taste receptors as such. They are, more generically, sensors. These sensors detect things about the body. They provide information that forms a basis for a physiological response. The nutritional and energy states of the body are perhaps what is detected. Instead of finding taste receptors throughout the body, sensors found more widely have a specialised role in the mouth. They give us information our minds experience as taste.

What began as an anecdote heard as an undergraduate student in the late 1970s now forms the basis for new ideas about the human body. It is an organism permeated with sensors monitoring itself in ways far more extensive than previously imagined.

'OHT2'

While I had an overhead transparency I nicknamed OHT1, there was never a specific ‘OHT2’ - hence the inverted commas. Had there been, it would have been the one shown here. The ideas conveyed by this image typically came soon after OHT1. This illustration also showed the textbook approach taken to the subject. It also provided a basis from which to start asking questions.

As with my OHT1 post, I am posting it here without further commentary. I will return to it at a later stage. For now, it is something for the visitor to look at and ponder over.

(From:
The Coloring Review Guide to Human Anatomy
By McMurtrie, WH, Krall Rikel, J & Rikel, JE.
Wm. C. Brown Co Publishers 1989)

OHT1

Before the advent of computer applications like PowerPoint or Keynote, lecture illustrations were often drawn or printed on transparent acetate sheets. These were then placed on an overhead projector and shown on a screen. When I taught anatomy and physiology in those days, there was one image I always used. That illustration showed the textbook approach taken to the subject of anatomy and physiology.

The illustration got the nickname ‘OHT1’. That meant ‘OverHead Transparency #1’. It was not necessarily the first transparency shown. (The first gave my name and contact details.) However, that transparency was of foremost importance. I used it to start asking questions.

I am posting it here without further commentary. I will return to it at a later stage. For now, it is something for the visitor to look at and ponder over.

(From:

The Coloring Review Guide to Human Anatomy

By McMurtrie, WH, Krall Rikel, J & Rikel, JE.

Wm. C. Brown Co Publishers 1989)

Saint Bartholomew’s Peanuts - Addendum

I have given the crux of what I wanted to say about the inhalation of peanuts. It showed that accepted explanations are not always explanations as such and that one must continue to think critically for oneself. Even about what is an accepted opinion.

The erroneous explanation is something else that has appeared in textbooks and was accepted uncritically. I read it in the same book that gave the incorrect description of what happens to the thyroid cornu during strangulation. (See: Prof Simpson and Textbook Strangulation.)

There is one further brief comment to add. That is about writing style. The authors needed to write their paper in a style that suited the requirements of an academic journal.

I first read about this study in New Scientist, a popular science magazine. It caters for a broad readership and must have an appropriate style. It was some years before I read the original paper. The contrast in writing styles was striking. There was a considerable difference between the academic journal and popular magazine writing styles. A description of the same study can have a very different feel.

I was excited by the New Scientist article. It was brief and to the point and written in a style that was easy to read. The study fascinated me. I referred to it in my lectures for many years after. The dryness of the original academic paper did not enthuse me. The study did not fascinate me when described that way. That was due to no fault of the writers. They had to follow the accepted writing style. Academic journals often prescribe what these should be.

Thousands of books are read every day for pleasure or interest. Academics are no exception. They do not confine their reading to academic literature alone. I have known many academics to be voracious readers of non-academic writing. Their reading is for pleasure.

There is little or no pleasure associated with reading academic papers. I do not recall hearing a colleague get excited about something read in an academic paper. I have heard plenty of criticisms. I have also heard - and experienced - how difficult it can be to write in the required style. The academic style of writing is neither simple nor is it natural. Journal editors sometimes comment on how laborious editing can be.

There is perhaps only one thing pleasurable about academic papers. That is seeing one’s name in print. However, that is only a transitory pleasure. It soon passes. Published works soon recede into the past. Only the most recent work gets read. Older works are not. The paper by Lowe and Ross Russell demonstrates this. The year 1984 was a long time ago. Were it read, the erroneous explanation of why peanuts find their way into the right main bronchus might be no more.

Reductionism

 

Can the human body be reduced to a set of clinical specialities?

(From:
Pearson, Vaughan & Fitzgerald (1996) - Nursing Models for Practice)

Reductionism

Can the human body be reduced to a set of parts?

(From:
Pearson, Vaughan & Fitzgerald (1996) - Nursing Models for Practice)

Biomedicine

Having mentioned [here] the numerical expansion in courses entitled Health Science and Health Studies, another word commonly appearing in course titles is Biomedicine. Alternatively, one may find the adjective Biomedical used - as in Biomedical Science or the like.

These courses are primarily science-based. The addition of Science in the course title is somewhat redundant. However, calling a course simply Biomedicine does not distinguish it sufficiently from medicine. Biomedical Science is the academic study of health-related topics. Medicine is about training to become a doctor.

Health Science and Biomedical Science are synonymous. The inclusion of the phrase medical provides extra cache.

The term biomedical will appear again. The medical model of the body - and disease and health - to which Western medicine adheres is also called the biomedical model. The two phrases are synonymous.

Nobel Prize Thinking

I found the following comments by Nobel Laureates on the role of conceptual/theoretical thinking in biology some time ago. I cannot remember the original source.

Biological understanding is the combined end product of two types of effort: the collection of observations (or facts) and the formation of relationships between observations. Scientists produce observations in the laboratory or clinic, and form relationships between observations in their mind (while in the lab, office, shower...) Both endeavours are essential. However, many practising biologists tend to dismiss the significance of conceptual or theoretical thinking in biology. In contrast, many Nobel Laureates recognise and emphasize the importance of such thinking, as follows...

'There is now a crisis developing in biology, that completely unstructured information does not enhance. What people want is to understand which means you must have a theoretical framework in which to embed this.'
Sydney Brenner (1927-2019)

'We've got to start thinking. We have all these individual components behaving in different ways, that interact in different ways, and we've got to somehow extract the general principles from that behaviour.'
Paul Nurse (1949-)

'All of the disciplines will benefit from this tremendous amount of information which is coming. But now we need people who can digest this information and can distil it into new concepts.'
Gunter Blobel (1936-2018)

'Conceptually driven research as opposed to end-use driven research, is what is likely to yield some of the biggest benefits ... Real curiosity-led work cannot be confined by a short time-horizon.'
Peter C. Doherty (1940-)

'The good scientist is not a drudge who collects facts like stamps and then searches these for a lucky conclusion: the good scientist chooses a problem of Nature, imagines an answer, and then tests to see whether imagination has been right. In science, imagination leads the way. Without imagination, without intellectual daring, science is dead.'
J. Michael Bishop (1936-)

'The rate of accumulation of knowledge or information is so vast, none of us can take it. But knowledge just adds, and you might think all this knowledge will make progress. But progress isn't based on knowledge, it's based on ideas.'
Sir James W. Black (1924-2010) 

A Particular Interest

In the UK, in the 1990s, there was a considerable expansion in higher education. More students than ever before were able to study on degree courses. As a result, there was an increase in the number and range of courses taught. Instead of the word degree, the phrase degree programme became common. A degree programme consisted of a series of credit-bearing modules of study. Success at each step through the programme depended on acquiring a prescribed number of credits.

As part of the higher education expansion, there was a considerable increase in the number of courses associated with health on offer. That reflected an extensive interest in health-related subjects. Most of these were non-vocational qualifications. Particularly numerous were students who did not want to follow a clinical or paramedical career. Training courses for such professions continued to be available. These were upgraded separately to degree status.

Courses titles like Health Science and Health Studies proliferated. New departments became established to cater for this, and existing ones expanded. In addition, departments of biological science and social studies were often called upon to provide teaching as appropriate. Noticeably, departments of medicine were not involved. Whether a degree programme merited a science (BSc) or arts (BA) degree was a product of the modules completed. Some modules were compulsory, others optional. Often, modules in a science-based subject were available to arts-based students and vice versa. Courses often took on a multi- or inter-disciplinary character as a result. That added to the appeal of these programmes.

Of shared interest to all students was the human body. A sound understanding of its structure and workings is fundamental. Modules on this topic were, therefore, usually compulsory. The phrase human body often implies just its physical makeup or anatomy. That overlooks its physiology. Anatomy and physiology teaching can be as separate subjects. Whether they can or should be separated is a moot point. Anatomy and physiology are intricately related. (The question of which has precedence is probably best left open.)

Medical schools typically teach anatomy and physiology as separate subjects. Teaching is by specialists from each discipline. (Sometimes even specialists from a sub-discipline.) Health-related degree programmes typically teach them as a single combined subject. That is to their credit. Where taught separately, the problem of how the two can be (re-)integrated arises. In short, they have a form of Humpty Dumpty problem. In addition, a biological scientist usually teaches modules on the human body. That means a somewhat reductionist approach is typically adopted. Opportunities for innovative approaches to studying the human body remained largely unexplored.

I used to teach students on health-related programmes. Anatomy, physiology and pathology were the areas I was required to teach. Wanting to find new ways into established subjects was a particular challenge. That was particularly so when adhering to a prescribed syllabus written in a reductionist way. There are plenty of facts to teach. There are plenty of books to recommend to aid the process. However, to do that does not educate fully. Teaching should not be merely a matter of transferring information from teacher to student. One must make the subject make sense and help others make sense of it. Maybe a student will go on to make better sense of it. That does not come from mere statements of facts.

Why there continues to be such an interest in health-based subjects is unclear. When I was an undergraduate, to suggest that it is because these topics are interesting in their own right would have been sufficient. I knew many students at university who were doing their subjects simply out of interest. Their careers after graduation were independent of what they had studied. Now, employment has much greater emphasis. It can begin in Freshers’ Week.

Several suggestions exist for the popularity of health-related courses. The implications are perhaps more pertinent. It means that problems in understanding health-related issues now have a much broader, well-educated set of contributors. Problems once confined to medicine are no longer so. What the doctor ordered/orders is now open to scrutiny. Issues in understanding health, illness, and disease are not limited to the medical arena. That is likely to influence how those problems are appreciated societally. A distinctively non-professional, non-vocational interest in health has now emerged. Now, issues in the philosophy of medicine have a wider ownership. The medical profession seeks to cure. From their respective perspectives, Health Science and Health Studies graduates each seek to understand. The study of clinical phenomena is no longer limited to a purely clinical context. In effect, issues in medicine are no longer the sole intellectual preserve of the medical or allied professions.

Saint Bartholomew’s Peanuts

Children sometimes inhale foreign objects which lodge in the airways leading to the lungs. All accident and emergency departments have seen cases where worried parents have brought in a child to whom this has happened. It also happens to adults who toss up a peanut in an attempt to catch it in the month. Although this may apply to any object of the right size, peanuts are the main culprits in Britain.

When inhaled, it is the right main bronchus (the airway leading to the right lung) that the peanut seems to favour. But why? (Of course, peanuts do not exhibit choice.) The answer usually given is that the right main bronchus is straighter, more vertical, and broader than the left. This reason continues to be accepted. It was even the response from ChatGPT (when asked in January 2024).

This reasoning lacks experimental evidence. It is based entirely on clinical observation and what is known anatomically about the arrangement of the central airway (the trachea) and its two branches (the left and right main bronchi). A moment’s critical thinking should cast doubt over the reason given.

The right main bronchus may be straighter, more vertical and broader than the left, but none influence whether a peanut ends up on the left or right. The characteristics of the airway AFTER the peanut has entered it can have no bearing on a choice made before entry. The reasoning is flawed. Whether this qualifies as reasoning is a moot point. It takes what we know about the airways and concocts an explanation without testing it. In so doing, it fails to be an explanation as such. It does not follow that what we know about the airways is complete enough to make a judgment. Clinical experience leads us to suspect that an inhaled peanut will more likely lodge in the right main bronchus. Chest radiography is necessary to confirm this. Only then can extraction be attempted. Anatomical knowledge without critical thought does not provide an accurate explanation. Here, critical thinking has been lacking.

Little known is that experimental work on this problem has been performed and published in 1984. (Some 40 years before ChatGPT gave the stock answer.)

It appeared as:

Tracheobronical foreign bodies - The position of the carina

Lowe, D. and Ross Russell, R.I.

The Journal of Laryngology and Otology. May 1984, Vol. 98. pp499-501

A brief, popular science report of this paper also appeared in New Scientist:

Why peanuts prefer the right lung

New Scientist 7th June 1984 - p25

Volume 102 Issue 1413

In a laboratory at St. Bartholomew’s Hospital in London, Lowe and Ross Russell suspended dissected tracheas and bronchi and placed a funnel in the top. They then lobbed peanuts into the funnel to simulate their inhalation. These found their way into the right main bronchus four times more often than the left. Thus, they corroborated clinical experience. They then cut these specimens into front and back halves and photocopied them. Using these, they analysed the geometry of the airways. The key finding was that the position of the carina was typically slightly to the left of the axis of the trachea.

Carina is Latin for the keel of a boat. The anatomical carina is the ridge that points upwards where the main bronchi divide. (Imagine the boat upturned on the seashore.) The carina is slightly to the left of the mid-line of the trachea. As a result, it deflects peanuts to the right when inhaled. (Imagine now a pinball machine.)

As I suggested above, this was an elegant piece of work. By this, I mean that it was clear and concise. What the authors set out to test and how they did it left little or no room for doubt. In that sense, there was something ideal about it. Unfortunately, experiments are rarely like that. Therefore, it was refreshing to find one. So, I can recommend reading it.

Note:

An omission from all accounts of why inhaled peanuts favour the right main bronchus is our upright posture. Gravity has a bearing. However, the role played by gravity is missing. It is not just to do with inhalation of air carrying a peanut. It is much less likely that any quadrupedal animals experience such a problem. Of course, giraffes may inhale things while browsing the treetops. Any such nuts or berries fall a long way and gain considerable momentum as they do so. Gravity may play a role in those cases. But this is conjecture.