“Rudolph the red–nosed reindeer had a very shiny nose. And if you ever saw it, you would even say it glows.”
Everyone has seen pictures of reindeer, for they are the animals that are said to draw the sledge of Father Christmas. Reindeers are protected from the cold by a thick skin and two coats of hair, a long coarse outer one and a fine, woolly inner one. The colour of the outer coat changes from dark brown in summer to a lighter brown in winter.
Reindeer in Norwegian arctic region has a distinct pink coloration at tip of nose.
Can Ince et al studied the functional morphology of the nasal microcirculation in humans in comparison with reindeers. (Why Rudolph’s nose is red: observational study –BMJ 2012;345:e8311).
The nasal microcirculation has important roles such as heating, filtering, and humidifying inhaled air, controlling inflammation, transporting fluid for mucous formation, and delivering oxygen to the nasal parenchymal cells.
The pathophysiology of many nasal conditions, such as congestion and epistaxis, is based on the regulatory mechanisms of the microcirculation.
Nasal mucosa has an important part in the uptake of drugs and responses to allergens.
The introduction of hand-held intravital video microscopes has helped in direct visualisation of the nasal microcirculation in humans.
These imaging instruments have had a special impact on intensive care medicine as they have shown the nasal microcirculation to be the most sensitive haemodynamic indicator of outcome and response to treatment. These instruments have also identified the microcirculation as a key factor in a wide range of other diseases, including diagnostic support and treatment responses in oncology.
Using the technique of hand-held vital video microscopy the authors characterised the microvasculature of the human nose and applied the same technique to reindeer for comparative purposes.
Intravital video microscope showed complex architecture of the nasal microcirculation, including the kinetics of flowing red blood cells, and provided new insights into the adaptive behaviour of vascular structures under varying clinical conditions.
An interesting finding was the presence of gland-like structures in the nasal mucosa. The explanation for the function of these circular vascular structures is mucous secretion. These structures are scattered throughout the nose and maintain an optimal nasal climate during humid weather and extremes of temperature as well as being responsible for fluid transport and acting as a barrier.
The nasal microcirculation in humans consists of hairpin-like vessels, microcirculatory networks, and crypt-like structures surrounded by capillaries.
“The microcirculation of the nasal mucosa in reindeer is richly vascularised and 25% denser than that in humans. These factors explain why the nose of Rudolph, the lead flying reindeer employed by Santa Claus to pull his sleigh, is red and well adapted to carrying out his duties in extreme temperatures. ”
Why Rudolph’s nose is red: observational study –BMJ 2012;345:e8311
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