A short primer on human physiology by Widmaier, who previously explained Why Geese Don’t Get Obese (and We Do) (not reviewed).
If you think of physiology as the medical science of how living organisms work, Widmaier (Biology/Boston Univ.) offers the Popular Mechanics version. To be sure, there is an obligatory chapter on the blueprints (DNA stuff), but the real purpose here is to reveal how we get energy from food (digestion), how oxygen moves from lungs to blood to cells (respiration, circulation, metabolism), how muscles work (locomotion), and what those master molecules (hormones, immunoglobulins, neurotransmitters) are all about. Some elementary chemistry comes into play as the author explains energy transformations, which involve the making and breaking of chemical bonds and the storage of energy in cells in the form of adenosine triphosphate (ATP), then sketches the special qualities and quantity of water we carry in blood, inside cells, and the spaces around cells. Having established this background information, Widmaier goes on to describe a variety of molecules and their receptors on cells that enable us to get on with our ordinary lives as well as respond to emergencies. For example, if you are bleeding from a severe injury, blood-pressure sensors in arteries alert the brain to signal the kidney to release renin. This hormone seeks out and converts an inert molecule in the blood to angiotensin, which powerfully triggers muscles in arterial walls to contract to raise blood pressure—and possibly save your life. Widmaier also points to the economy of nature in using single-parent molecules for multiple purposes. The much-maligned cholesterol is actually an essential ingredient of cell membranes, a contributor to bile salts, and the backbone molecule for the manufacture of cortisol and sex hormones.
Not everything you need to know to get into med school, but enough to inspire appreciation of the wisdom of the body and perhaps lead a student to want to learn more.