Why have we got smooth muscle around our bronchi (tubes in our lungs)?

I am a general practitioner who hits “retirement age” in 3 days. I do feel qualified to ask this question but not really to answer it. It has been bugging me my whole career, but I have realised most people never contemplate this backwater of physiology.

I always expected to ask someone in the know and get a clear answer. I asked professors of paediatrics, as these muscles seem to cause a lot of trouble in young people. Nothing. I moved on to professors of respiratory medicine, as a lot of their work relates to this biological machinery that can narrow our airways. They smiled, looked around quizzically and got on with their work. More recently I trapped a respiratory professor in a pleasant restaurant, but he was not really interested. He proposed that the muscles were embryonic vestiges of bowel muscle.

You may not be interested in my explanation either. But it is an important question. These muscles are in a critical location in our lungs. The inappropriate contraction of these muscles, called asthma, is a significant cause of death in adults. It tragically happened to one of my otherwise healthy young patients and has been a near miss on a number of occasions. During that huge thunderstorm in Melbourne a few years ago, these muscles went on a rampage. We have drugs to relax these muscles that are contained in a blue inhaler and used by many people around the world. We know a lot about these muscles and how they work.

“These smooth muscle cells have muscarinic M3 receptors on their membrane. The activation of these receptors by acetylcholine will activate an intracellular G protein, that in turn will activate the phospholipase C pathway, that will end in an increase of intracellular calcium concentrations and therefore contraction of the smooth muscle cell. The muscle contraction will cause the diameter of the bronchus to decrease, therefore increasing its resistance to airflow.”


Searching the internet, has provided no explanation. So, I will have a shot, excused by unrequited inquisitiveness and my age.

My only real experience of these muscles in action is wheeze, the symptom that is caused by their contraction. The noise is generated by the air we breath going through a narrow tube. If you take a deep breath with your mouth open you will hear a soft noise, if you do it again with your mouth shut, you will get a lot more noise in your nose. The same amount of air will make higher pitched noises as the tube narrows. When the tubes get narrow enough they start to hum and whistle and we can hear a “wheeze”.

Living in London for a decade, I noticed that children wheezed a lot. It was usually with a viral infection and was almost always worse at night. It seemed relatively harmless for most, but a few had difficulty. I treated them with the medications we had available, and noticed that most of them settled down as they got older.

I imagined that the viral infection was causing some swelling of the tubes and narrowing them somewhat. I could explain the wheezes disappearing as children got older because the tubes of their lungs were getting bigger. The deterioration at night, something that was particularly evident with croup, was not so easy to explain.

Traveling piqued my interest in this phenomenon. In 1981, I got off a train at Linkoping in Sweden at 1am in the morning and the temperature was minus 30 degrees. The hairs in my nostrils froze in a snap and I began to wheeze gently for the first time in my life. It didn’t last long as we walked knee deep in powder snow to our friend’s apartment. In the early 90s when we returned from London to live in Darwin our wheezy child stopped wheezing altogether. The air was cleaner and it was a lot warmer, especially at night.

Someone told me that the surface area of our lungs, as an adult, is the size of a tennis court. There is a tiny membrane between our blood, pulsing at 37 degrees, and the air we breathe. How do we possibly stay alive and not die of hypothermia? Especially in Sweden! The solution is that our body heats and moisturises the air between entering our nose and delivering the oxygen to our blood in the tiny sacks at the end of the muscular tubes of our lungs. When we breath hard, we bypass our nose, but we are generally exercising when we do this.

Could these muscles have a role to play in temperature regulation? It seemed quite possible. To warm air, it needs to be in contact with a surface, so the thinner a tube the more likely it is to warm during its passage. But the same amount of air passing through a thin tube would travel faster and have less time to warm. What if we didn’t need so much air? That is the case when we are not exercising, especially when we are asleep. Could this be useful when we are at rest, particularly when we are asleep?

The other effect of reducing the diameter of the tubes is to reduce the volume of the tubes. It is dramatic. If you halve the width of the tube, the amount of air being drawn in is a quarter. So for a small reduction, perhaps to 3/4 width, only half as much air would need to be drawn in through our nose to get the same amount of oxygen to our lungs. This sounds handy, less air, more efficient warming and same oxygen.

It seemed to explain why children get wheezier at night. I was told by my Swedish friends that all Swedish footballers wheeze for the first few minutes of the game in winter. Could this explain exercise induced asthma, where the airways constrict until the person is generating enough heat from exercise? Cold air is a well known trigger to wheeze. A person probably also has some swelling in the lining of the tubes when this happens; allergy or a viral infection. Clearly things go horribly wrong with this mechanism at times, causing severe asthma, but a lot of wheeze can be explained physiologically.

So what is my answer to what has become a rhetorical question?

The muscles around your bronchi protect you from excessive heat loss when you are not exercising, and particularly when you are asleep. You can get by at those times with a lot less air coming into your lungs, and so can conserve heat efficiently. You can survive and sleep in cold weather and cold nights without becoming hypothermic.

Now that sounds like evolution.

Whether or not you like the answer, you can start asking experts the question. I think you will be as bewildered as I am by their inability to answer. You should at least consider why that is so and what it says about our profession? No doubt some of you will search the internet. Please comment if you find the answer out there.

Looking after your own

We are living in a moment when there is evident risk to every soul on earth. We worry for the people we love if not for ourselves. My good friend, young and healthy, has just spent a week in hospital and 4 days in intensive care in a personal battle with this virus. It is a depressingly passive experience lying with plastic lines and tubes, depending on oxygen, coughing discretely when others are around. All the while alone, removed from family and friends. Dying was a real possibility. We talked about it on the phone. The virus spread and wreaked havoc in her family. Her three children had both parents in hospital for a few days, all separated and unable to help each other. This was in Australia in a street near you.

Behind the face shields in intensive care, others hovered, their eyes concerned, concentrating but creasing kindly when looking into another. A gloved tap on the arm, and patience with the endless shuffling of bedpans required by a person whose dignity lives only in facing this dark unmeasured threat to their life. It is a kind of love. These caring people matter immensely. To all of us. Time will inevitably take quite a few of us to the edge of this slippery chasm held back by special people decorated only with gowns and gloves and masks. There will be no one else.

Meanwhile the children danced and played with some delight with a visiting aunt who, recovering from the disease, found herself taking care of energised children who were not allowed out. Their young bodies unaffected and one, despite coughing a little like the rest of the family, could not manage to give a positive swab to the persistent masked visitors in gowns. Like other children around the world, they were somehow protected from its power; the younger, the stronger even if afflicted with other conditions. Cryptonite of youth.

It is a wonder of this condition that the deaths that occur mirror almost perfectly the ‘natural’ rates of death in the community. It is for this reason that despite reaching 4,000 deaths in Italy, this virus had not taken a single life under the age of 30. The problem for all of us is that this ‘natural’ curve of human attrition is delivered over a period of 14 days, and the other health problems facing us do not go away. It is a massive impost on health care and society and a disaster facing us all. But it still has this compassionate element – to take we older folk in stark preference. We, who want nothing more than for our children to outlive us.

Health care workers, paramedics and aged care workers are now the farmers in the drought, the police on Saturday night and the firefighters of the summer. We are needed desperately, our attention, our care and compassion. We will be needed for sometime and it could be dangerous. Some are going to catch the virus. It is going to be tough, but it is going to be much tougher for the older members of our professions. The haunting image of an aged care home in Spain, abandoned by carers who may themselves have been sick, must guide our future.

I hear some of my colleagues saying they did not sign up for this, or they have a young family. This is stark. The younger you are, the safer you are. Society needs young health professionals to step forward and engage. Your older colleagues will be there with you but there will be no equality when the virus hits. This is a real test of civility, of commitment to society.

We sit under a cloud of adversity, wondering what will become of us, of our loved ones. Will we come through this, will we all survive? But we are your own. Please take care of us.

Could my death go viral?

Image by Meredith Reardon

I am afraid. My eyes fill a little, mostly at night when I consider my future, our future. I have lived a full life, more focussed on the world around me than my family. My lovely wife has channelled her energy to family and friends. Together we have stood easy in our space, even when apart.

We share some sadness; a fatal crash, estranged loved ones and health has become more fragile. We have a wealth of offspring who pluck our sense of being. We have always loved to live in the villages and spaces we moved in, with little concern for the future. We have had good parents, and siblings who have found their feet. My parents still go about their lives, playing bowls and music as they approach their centenary. My body is likely strong.

I have always anticipated my death a little, and felt vaguely cosy with the tears that I would share with my cherished sons and daughters and those grandchildren who had enjoyed exploring the opaque and cheeky thoughts of elders. Even the regrets that we didn’t do more together, that I didn’t show my love enough, or wasn’t there for some when I should have been, could be resolved in that final reckoning. If I was younger my one love in life would carry me, my family would lift my mood and surround me. Perhaps even some of the people I worked with would join the throng and replay forgotten moments. If I was older, the sheer number of offspring would sustain me and I would go easily.

With the news of this virus and my work amongst potential victims a new contagion has begun to haunt my dreams. It is bleak. What if my wife or I were to catch it and get sick? How would it be to need increasing support and finally, to know one of us could not recover? What then?

Would I die in an expensive shiny intensive care bed, my tubes and vital signs attended by masked and selfless strangers, fading into a world where a distant and sunless window occasionally showed a fleeting familiar face? Or less alone in a ward of others suffocating slowly while sharing our stoic denial or whispered acknowledgement of our very possible future? Perhaps I will be amongst a hoard in a warehouse, given what sustenance the conscripted carers can find. They may be the untidy recovered or people out to make some money to pay off recent debts.

Whatever the stage, whatever the course, we seem deemed to tackle this grim reaper alone. Any peace cut by sirens of the tiny oxygen meters on our fingers or the soon futile wailing of ambulances arriving at the barred doors below. Or the creaking of lines of makeshift beds and gasping neighbours. Alone in a sea of drowning strangers.

That is not what I want for me, for my family or anyone. Let me have a little of my own future, and the people I love. Even one to be with me will make me smile and wonder at what might have been and see inside another’s eyes. I think we can and we should.

But how?

Let households be the victim of this wanton infection, strong together within familiar walls. Let resilient children play with their snotty parents, and lovers lie with their fevered friends. They will joke and laugh and cough even as they feel a shared fear of the future. Take out the elders if they wish and test them, returning immediately if they have the little beast within and later if not. The children will wonder what the fuss is about and happiness will replace fear as each recovers, cared for by ones affected not at all or in a little way.

The home while coughing will need help to bring supplies. They will wave together through clean blue windows and call gratefully to the helpful neighbour who turns away. They might go outside in their garden or play music and sing in a balcony choir. Every now and then one will get very sick, and if there is somewhere better to be with a ventilator or new treatment, they can go. They can be visited there and kissed and hugged by their recovered family. And if all fails or they are making a slow recovery, they can go home if they wish to be cherished.

They say things will change with this king of germs. Perhaps it is a chance to discard the notion of health and even being as an individual experience.

Who knows who blows?

Could we greet each other in a way that meant we kept 1.5m apart?
Photo by Guilherme Stecanella on Unsplash

Few of us blame the Government for this virus pandemic but on a dreadful day when Australia has twice as many new cases as China (and a 60th of the population) we have to ponder whether we have done enough. Peter Wener in the Atlantic points to a major issues in the USA such as, “… the decision to test too few people, the delay in expanding testing to labs outside the Centers for Disease Control and Prevention, and problems in the supply chain. These mistakes have left us blind and badly behind the curve, and, for a few crucial weeks, they created a false sense of security. What we now know is that the coronavirus silently spread for several weeks, without us being aware of it and while we were doing nothing to stop it. Containment and mitigation efforts could have significantly slowed its spread at an early, critical point, but we frittered away that opportunity.” It sounds a lot like us. Five hundred people getting together at the moment is NOT safe. It is very hard to get tested, and we are being told it may be more difficult.

We have seen TV presenters, film stars and politicians come down with the virus. These people certainly mix with more people than we do day to day, but there are not many of them. So if we extrapolate back from their numbers and determine the rate of infection we will arrive at figures many orders of magnitude above that being reported. Let’s face it:

It is infectious, it is deadly and we need to stop it.

Economic predictions of impact are unlikely to be accurate and should not be listened to. Minimising the spread of the virus will have the most positive economic impact. Short, sharp, severe. Norman Swan has been getting air time to promote more health of the nation approaches. If we stop the growth, we can reopen schools and kindergartens. We can probably keep schools open now for children of emergency workers, health workers and other services that are understaffed.

Most of all we need to consider testing. At the moment we are testing a lot of worried people and groups of people who are in contact with an infected case. If we take a community view rather than an individual view and extreme social distancing is in place, we can check one member of a potentially infected household with symptoms and declare it positive or negative. That household should then be supported at home. Children are likely to be infected very quickly and have no difficulty. The disruption of treating individuals in this situation is massive and quite likely to lead to asymptomatic people thinking they are clear. Household members over 70 in infected households can be removed if asymptomatic and offered alternative accommodation if they do not have the virus after brief quarantine and testing.

Small towns with limited movement in and out can test the first locals with fever, and no travel or contact, as sentinel cases. If the sentinel febrile person is negative then we can assume safely that other fevers in that community are almost certainly negative for a period – perhaps the next seven days. This will be especially important when we add the usual winter viruses to the mix. Obviously any new arrivals with symptoms must be tested.

Regions, such as Central Australia, Cape York and Northern Western Australia (and many others) lend themselves to a regional community approach with community-based testing. The experts on our nation’s 60,000 year old cultures are at grave risk and require extreme measures of preservation. This requires checking all arrivals into the region (which is often one or two roads and an airport or two) and testing any of these who are symptomatic or develop symptoms over the next 14 days. We can tell them when we check them at the regional boundaries. In two weeks they become part of the “viral control” community. We will need sentinel testing in communities, perhaps one or two tests per week. The extraordinary thing in Central Australia is that this will require less than 100 tests a week. If we can “bank” the saved tests, we will be able to carry out contact tracing in the way Singapore has done.

If we are short of tests, lets think about how to use them effectively. It is time for extreme social distancing. Whatever we are putting in place, we need to know where the virus has spread.

The Authority of Colour






Toni Morrison wrote:





Waiting for the World to Change

I was waiting to board the plane from a community back to Alice Springs and a young client who I had seen the day before  was in the queue. It was great to see she had decided to move on. She had a pillow and a lot of hand luggage as well as her chubby young baby. I offered to carry something and she held out her pillow. I took it. We walked to the plane together sharing a little history and contemplating the new life she was heading towards. She beamed hope and liberation from a very tough time in her life.

On the plane she went to the back, row 23 and I stopped at row 1. I told her I would ask a hostess to bring the pillow down when she was settled in. I put on my headphones and started to listen to John Mayer. Once the door was shut, I asked a lively young, very blonde and Aussie hostess who came from the back of the  plane if she could give the pillow to the tall young woman in row 23 with a baby. She looked at me quizzically, turned her head to one side, pursed her lips, but took the pillow. I was puzzled that she hadn’t noticed the striking appearance of the woman, and I wondered if there were a lot of babies in row 23.

She came back and checked, “You mean the dark one?”

“Yes”, I said.

I worried for that young woman from the bush who will be trying to make her way in mainstream Australia. It is tempting to try and understand what was going on in the young hostess’s mind. She was clearly a caring and well intentioned young person. I think we need to own the state of the young hostess’s mind as a nation and realise how far we have to go to educate ourselves and embrace our Indigenous peoples and cultures. When it comes down to it, the complex cultures of our ancient forebears define our space in an increasingly global cultural ‘mash-up’. The alternative is that our collective ignorance defines us.

Is old age a battle or a massacre?

















It’s not My Health Record, it’s Yours

Daniel Chen



Whose Health Record?


Who sees the value?


Is it Accurate or Complete?


Ownership or Access?



Dangers of a Single National Database




Making Corrections



Curating Your Health Record


Who Benefits from a Shared Health Record?





Why Would I Want To Opt Out?

Being involved as Citizens and not Consumers


What Happens with Dr. Shonky, Stays with Dr Shonky.



The Special Case of Children



Is there a Utopian Future?







I believe that Australians should opt out of MyHR if:





Declaration of compound interests


Killing the Micro-Biome











Please do not use this test.


Long view to Gillen from Undoolya

The Centre of it all: end of life


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