Week 2 Overview 1

Hello! We start this week with a trip down the digestive tract. Meters of guts and a few sphincters! It’s actually a beautifully designed system, and reminds us that we are really a long tube with the rest of us wrapped around it. We’ll learn about essential nutrients. When we oxidize our food to extract its energy, we are doing what a coal-fired power plant does. But because we use enzymes to do it, we capture the energy efficiently in ATP, the super energy storage molecule. We oxidize without having to burn. Maybe one of you will invent a way to store solar energy as ATP–it’s biology’s way. The body is a machine. The skeleton is the basic framework.

Since the body has to move around, it’s equipped with joints; some of which are very strong and others very flexible. Joints can be braced with ligaments. To move the joints we have excellent motors that pull and relax, called muscles. They attach to the bones via durable cables called tendons. All of this needs to be integrated with the control systems of the brain.

We look at muscles next, at the microscopic level: how do they manage to contract? That’s the job of the sarcomere, a tiny unit of molecules that slide past each other when given the right amount of ATP. Muscles are either fast-twitch or slow-twitch; which is best for you? We’ll find out the difference. And, since arthritis is one of the most common diagnoses in the world, we consider the different kinds of arthritis, so we know how to approach treating or, much better, preventing them.