In Anatomy & Physiology, we are about to start section 10.4 Capillary and Fluid Exchange. This is a complicated section dealing that helps to identify the location of water in the body (60-40-20 rule), describe the structure of capillaries, and explain the factors (blood pressure and osmosis) that affect edema (i.e., swelling).

We needed a refresher on osmosis, which we talked about way back in our first unit (an amalgam of topics ranging from directional terms to homeostasis to body systems). So as a review, I had students in groups whiteboard a diagram and description of osmosis.

They included an intentional mistake in their presentations (a la Kelly Oshea’s Mistake Game), which helped produce a more interesting conversation about the process and helps to normalize error. There were a handful of unintentional mistakes/differences/misconceptions as well, which is always welcome!

One of the mistakes in the whiteboard shown above was that the water molecules (solvent) are shown only moving toward the area of higher solute concentration. In reality, water molecules move both ways (so they needed an up- and down-arrow), but the net movement is toward the higher solute concentration. With whiteboarding and the mistake game, we got to talk about this and clear up these kinds of misunderstandings!

On to capillary fluid exchange and edema tomorrow!

It’ll be…um…swell!