General News
18 May, 2025
Small Vessels, Big Impact
Our local GP columnist, Dr Felix Ritson, has another interesting Call the Doctor column for us this week, it's all about the microvasculature. Enjoy
This fortnight, I want to describe an incredibly important part of our body, our microvasculature.
This will take a little explaining, so I hope you can bear with me.
An astounding and wondrous fact about reality is that the view out of a plane window often looks like the view through a microscope.
Nature shares patterns that seem to repeat themselves. The theoretical image of an atom looks somewhat like a galaxy, for example.
I would like you to imagine looking down from a plane at a river, and pretending that the plane is flying upstream. As you look down at the thin and winding body of water, you notice it becoming smaller and smaller, with tributaries and forks in the river often dividing it.
Eventually, the river becomes a creek, then a stream, then a trickle, by which time we have lost sight of it from the plane.
This ever-narrowing and dividing body of water has the same structure as our blood vessels.
At its widest point, our vascular (blood vessel) system is about 3 centimeters wide, and it progressively narrows until it is about 3 micrometres wide.
That is so narrow that red blood cells can only pass through single-file, 30 times thinner than an average human hair. These microscopically thin blood vessels are collectively referred to as our microvasculature, and they are extraordinarily important.
In essence, the role of our heart and blood vessels is to deliver blood to our microvasculature.
It is only in the microvasculature that exchange of goods occurs, all other blood vessels just pipe things around.
The microvasculature exchanges oxygen and carbon dioxide, transmits hormones and glucose, absorbs ingested nutrients, deposits proteins and minerals for building muscles and bone, allows the immune system to target foreign agents, controls inflammation, and in the kidney filters waste products that become urine.
Every micro-inch of your body has a rich microvascular network. Needless to say, harm to the microvascular system causes widespread illness.
Sadly, the microvascular system is susceptible to harm and hence often responsible for manifestations and symptoms of disease.
Toxicity from chemicals (especially those in tobacco) and high blood sugar destroy our microscopic vessels.
Chronic high blood pressure or episodes of significant dehydration will also disrupt this system. This harm causes nerve damage with resultant peripheral pain, brain cell atrophy leading to cognitive decline and dementia, chronic kidney disease, heart failure, erectile dysfunction, vision impairment, etc. etc.
A reason why you may not have heard about what is clearly such an important part of your health, is that there is no readily available test for measuring your microvascular function. An ultrasonographer will look at the blood flow through your larger vessels, an optometrist can look at the vessels in the eyes, but no-one can easily determine how well your microvascular system is operating.
It is only the symptoms that suggest if things are going poorly.
Don't smoke, avoid unnecessary chemical exposure, ensure your blood glucose and blood pressure are well controlled, maintain good hydration, and you’ll have good odds of living a long and healthy life, thanks to a robust and efficient microvasculature.w