Lesson 1.2: Isotonic, Hypertonic, and Hypotonic Cells and how it relates to Homeostasis

Welcome to lesson 1.2 of Scipop! Today, we will discuss the balance of isotonic, hypertonic, and hypotonic cells. It is interesting when diving into the world of cell osmosis (the diffusion of water in cells) and how it responds to the environment in our body. The four things we hope you understand by the end of this lesson are the three types of osmosis balance in your cells and how this all connects to our previous lesson on homeostasis.

Hypotonic cells

To introduce, all cells have two concentration levels of solutions inside them, one concentration is on the outside of the cell, while the other concentration level is on the inside. Hypotonic cells are cells with too much water diffusion in them on the inside rather than the outside. This means there is an imbalance of water between the two concentration levels. When a cell has water pass through it, it can either be too much, too little, or just right. Remember, hypotonic fits in with the TOO MUCH category. A good way to remember hypotonic: hypo sounds like hippo, hippos are heavy, and hypotonic cells carry a heavy amount of water inside them.

What causes concerns about hypotonic cells?

Now, having hypotonic cells is not desirable. When too much water travels into the cells, it disrupts the process of homeostasis in these cells, which we have learned in the last lesson is not healthy for the body. The concerns of hypotonic cells are the risk of your cells swelling or even exploding from too much concentration of liquid. Think of your hypotonic cells as Spongebob drinking too much water. When he drinks too much water, he expands! That is exactly what happens to your cells when there is an uneven balance of water on the inside rather than the outside.

Hypertonic cells

Think of hypertonic cells as the exact opposite of hypotonic. Hypertonic cells occur when there's not enough water in the inner concentration of the cell. Water will flow outside the cell only, instead of inside and outside. This deprives the cell of the correct amount of water to function. A concern of hypertonic cells is the imbalance of homeostasis, but the main problem is the shrinking of cells when a cell is hypertonic. When a cell lacks the correct amount of water, it will wither. If you're a big SpongeBob fan, you can remember hypertonic cells this way. Do you remember the episode "Tea at the Treedome"? Well, in that episode, SpongeBob goes to meet Sandy for the first time. When Spongebob enters Sandy's house, It's full of air, not water. Spongebob realizes his body can't function in the air, so his body shrivels a little bit due to the deprivation of water he's always been submerged in. That is exactly what happens to hypertonic cells!

Isotonic cells

Isotonic cells are cells that are in a balanced environment, meaning the concentration of solutes (like salt or sugar) inside the cell is equal to the concentration of solutes outside the cell. Imagine if you have a bag of popcorn and you pour just the right amount of salt on it—not too much, not too little. The flavor is perfectly balanced, just like an isotonic solution.

In terms of homeostasis, isotonic cells play a key role. Homeostasis is all about keeping things in balance, like temperature, pH levels, and concentration of substances. When cells are isotonic, they’re not gaining or losing water. This stability helps cells function properly, so they can carry out their jobs effectively without getting too swollen (which happens in hypotonic conditions) or shriveling up (which happens in hypertonic conditions).

So, in summary, isotonic cells help keep everything balanced and stable, which is essential for homeostasis. Without that balance, cells could get damaged or stop working, which would affect the whole body.

Thank you so much for reading blog 2 of Scipop! We hope you learned a lot from us this time around. Updates on blog 3 will be released soon! Until next time, stay curious!