[Bloggers warning: read on ONLY if you enjoy biology and medicine, and are not one of those who recoils at the discussion of bodily fluids.]
Last night was the first in a week during which I did not wake up at 2 or 3 in the morning gasping for breath. Each time, I had to go through what seemed like an entire box of tissue to clear all the sticky fluid out of my nose and throat. Finally, I was able to breathe again, and while trying to get back to sleep, had ample time to contemplate the origin of these copious fluids. How is it possible that for the past week, 24 hours per day, my cranium could manufacture so much disgusting fluid?
It's a good thing we have the internet, and I have some time on my hands because I'm sick.
Let's start at the very beginning, the Science of Phlegm, shall we?
Phlegm is sticky fluid secreted by the mucous membranes of humans and other animals. Its definition is limited to the mucus produced by the respiratory system, excluding that from the nasal passages, and particularly that which is expelled by coughing (sputum). Its composition varies, depending on climate, genetics, and state of the immune system, but basically is a water-based gel consisting of glycoproteins, immunoglobulins, lipids, etc. Phlegm may be of several different colors. (Wikipedia)
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. It is a viscous colloid containing antiseptic enzymes (such as lysozyme) and immunoglobulins that serves to protect epithelial cells in the respiratory, gastrointestinal, urogenital, visual, and auditory systems in mammals; the epidermis in amphibians; and the gills in fish. Snails, slugs, hagfish, and certain invertebrates also produce external mucus, which in addition to serving a protective function, can facilitate movement and play a role in communication. Mucus also contains mucins, produced by goblet cells in the mucous membranes and submucosal glands, and inorganic salts suspended in water. The average human body produces about a litre of mucus per day. (Wikipedia)
I also found a great article on phlegm by Flash Gordon, M.D. (really). The good DocFlash cautions us not to use to many drugs that are intended to "dry us up" because the result is that phlegm in the small airways of the lung dries up and creates blockages - which our body then involuntarily tries to cough open. This promotes more coughing, and can also result in bronchitis.
But that's not all there is to know about phlegm. It turns out that phlegm has a rich and varied history, including many important cultural values. Think, for example, what the world would be like without the works of Ian Phlegming, author of James Bond. There were many important Dutch and Phlegmish paintings in the 16th and 17th centuries. Why, there is even an association of breeders of phlegmish giant rabbits. And who would know that phlegm can support vast resources of fish, which must be more easily caught due to the viscosity of their habitat, resulting in overfishing in the Nose (and the Tail) of the Grand Banks, and the Phlegmish Cap, another fish-rich region east of the Nose.
Where would Europe be without Phlanders? Would it be the same without a Phlegmish community? (The sound of all that hacking and coughing must be maddening!) There is even a society to study the genealogy of phlegmish people.
At this point, I need to pay homage to a man who has helped put sticky nasal fluids on the map and into the common lexicon of America, Kinky Friedman the Jewish cowboy. With one song he wrote and has sung everywhere, he has elevated the runny nose to a high stature:
"Old man Lucas
had a lot of mucus,
hangin' right out of his nose...."
And finally, because I am who I am, I need to point you to the lowly hagfish - not really a true fish, not really a vertebrate, but a fascinating animal that lives in the deep oceans of the world. The hagfish is a champion of mucus, and you have to watch this science video to see it.
I hope you learned something today.