THE SENSES

 Grade nine science is very biology based, and I enjoyed revisiting human senses. Like Pluto, that was a planet when I was in secondary school, and now downgraded to a less prominent celestial body, my understanding of the senses have altered, with taste maps debunked, umami (savory) and  just the beginning, and our understanding of  5 evolving to many other senses (this article lists 18, but I suspect is not the final count, given our sense of time is much clearer than the author suggests even in 2019) still accumulating. The classic sweet, salty, sour, and bitter evolved to an understanding of taste receptors (I-IV) that were a further refinement from the taste buds we were taught. Now, taste receptors are known to be in the gut and not limited to the tongue, and the ability to taste still broken down into 4 subsets, but the receptors are clearly able to distinguish

There are many similar refinements that deepen my amazement of the magnificant human organism. Here is one example:

The retina sees colour  and shadow, but even in the absence of sight, the eye is capturing the circadian rhythm guided by the rotation of the earth with awareness of light and darkness. 

Other facts that I had forgotten: the iris dilates by a radial smooth muscle contracts, with constriction by a central sphincter.

Concomitant to my daughter's curriculum, I have reading Bill Bryson's The Body with a dear friend and colleague. It's been a fascinating review of the wonders of the body, and the horrors and wins of a long history of medicine. That anyone worships a health care worker shows how often we forget the past. Good thing for the most part. We've had a good run of it, with antibiotics, surgical advances, cardiovascular care,  cancer immunotherapy a successful last century. However, we need to remember that we were not successful very recently, and there is no time for hubris, but humility. No hero worship necessary. The historiens can tell you more.