Here’s a structure and function question for your students to think about: how can a sponge soak up so much water? The anatomy and physiology answer: the same way your lungs can exchange blood gases so quickly. Structurally, a sponge has a large surface–every pore increases the amount of contact between the porous cellulose fibers and water molecules. Similarly, alveoli in the lungs increase the surface area for the uptake of oxygen from the environment. Then capillaries next to the alveoli allow gas exchange to occur between the internal and external environment.
Another question to pose to your students: what happens to a sponge when the liquid absorbed is spilled coffee instead of water? What happens to the larger molecules that get stuck in the pores? They stain the sponge, and the sponge must be rinsed out. What’s an analogous process in your lungs?
One more thing to consider: what if that spilled coffee is the last cup in the pot and has solid coffee grounds in it? The solid particles on the counter can be removed by the sponge, but now the sponge must be washed thoroughly, maybe even bleached, and some grounds may have to be picked out manually.
Our lungs perform a similar function with every breath we take. Rarely is the air we breathe perfectly proportioned atmospheric gases. Our respiratory system adapts to ranges in oxygen saturation with changes in altitude, changes in humidity (desert to rain forest or winter to summer), and changes in particulate matter (from dust to pollen to pathogens). It also adapts to the occasional guzzle of hot coffee that goes down the wrong way. It’s an amazing system!
Additional Reading: It Takes Guts to Teach A&P
Understanding the respiratory system
To help students understand the respiratory system, take a look at our infographic explaining the structure of lungs and how the lungs and diaphragm work in tandem, allowing us to inhale and exhale.
Download: Human Body: Respiratory System Infographic
Explore the mechanics of breathing and the physical laws that explain lung function with a reading that explains gas laws in relation to inhaling and exhaling.
To supplement the reading, students can simulate lung function using the miniature lung function model. This model illustrates how the movement of the diaphragm affects pressure and volume during human respiration. They can also assess their personal vital capacity, tidal volume, and expiratory reserve with a spirometer and total lung capacity with the lung volume bag set. Some absorb and release a high volume of water and some very little.
Respiratory system models help students get a sense of how all the working parts come together as a system before they complete a dissection of a sheep pluck, which includes the heart with aorta and lungs with trachea. In a demonstration, use a hose and foot pump to carefully inflate the lungs, showing students how the air sacs expand. Then ask students to make thin slices of the lung tissue reinforcing the spongelike texture of lung tissue. After the macro examination of the respiratory system structures, a microscopic examination of lung, trachea, and larynx tissue can drive home the concept of structure and function.
Whatever analogies you choose to help students learn the respiratory system, you can rely on Carolina for a wide variety of products to support your teaching and student learning. We know your students are ready to soak up every drop of information you provide.