Welcome back! Today, we’re going to be taking a closer look at the small intestine. Before we do that, we need to formally address how the body is organized. We’ve been talking about system and organs for several weeks now. I like to use the example of mailing a letter or package. Without a complete address, the letter won’t arrive. The body is also organized:

We’ve discussed everything but tissue at this point in the unit. Villi, or the tissue in the small intestine, are today’s focus. Just like doors let people into and out of buildings, the villi are the mechanism for allowing nutrients to move from the small intestine to the bloodstream.

Students will be using this simulation to test different villi heights. They’re tracking how many cells are present and what percentage of food molecules are being absorbed. We’ll dive into the simulation results in more detail tomorrow.