Dear Biology: This Is How My Layperson Brain Works

Photo Courtesy of Wikipedia

I am a layperson. I am a Communications undergrad with an MBA. I am no Science major. What on earth is this photo supposed to mean???

We've got only one week left before our Philippine NMAT examination in Los Angeles. I'm obviously reviewing for the Biology subtest. It's the first step in hopefully becoming a doctor one day and doing medical missions in the Asia-Pacific region.

The nice thing about having a husband who's also a healthcare provider is that you can nicely ask him to "stop / go / listen" when explaining medical concepts. He may sound like a book at times when explaining things, but he can certainly correct me when my rendition of the concept is totally off.

Sure, I can grasp the concept of the above illustration; but that doesn't always mean that I'll get to remember/recall it when needed at an instant.

So, I'm making a blogpost about this concept with hopes of easy recall in the future...

The labels "hypertonic", "isotonic", and "hypotonic" refer to an environment. The "red stuff" inside the circle are the erythrocytes, or red blood cells. I'd like to call the erythrocites the "Mama Cell", and this Mama Cell has kids, and their "home" could either be "hypertonic", "isotonic", or "hypotonic".

For purposes of recalling a...

• Hypertonic Solution: The kids are playing outside (the fluid just outside of the cell = this is known as "extracellular fluid") and they are hyper and want to stay outside and play. Mama Cell gets upset and "crenates" (or shrinks) as she yells out harsh words (in the cell's case, water gets pushed out) out of her mouth (hence the outward direction of the arrows in the photo above). That outward movement of water from the cell then balances out the over-abundance of solute in the extracellular fluid just outside of the cell.
• Isotonic Solution: This simply means that the solution has a concentration of solute that is equal to the concentration inside the cell. In my tiny mind, I chose to break it down this way: the prefix "iso-" can be likened to "ISO" certification. For example, if a business establishment / institution is known to be "ISO-certified", that means that they must be doing something right. In the case of an isotonic solution, it means that there is balance or equilibrium. 
•  Hyptonic Solution: The kids are lethargic while playing outside (in the extracellular fluid) because they don't have enough solute ... because guess what? Mama Cell has been hogging most of the solute inside (higher concentration of solute) and is therefore swelling up and getting fat!!! In order to reach equilibrium and keep Mama Cell happy, she needs to take in more water (hence the swelling and bloating) to balance out the over-abundance of solute inside of her, hence the inward direction of the arrows in the above illustration.

I may have just confused you even more. But just to compare, here is the explanation directly taken from the MSA NMAT Reviewer in Biology:

Question #1: An erythrocyte is placed in a beaker with a hypertonic solution. What do you think will happen to the cell after several minutes?

1. It will crenate.
2. It will plasmolyze.
3. It will become turgid.
4. It will become flaccid.

Answer is #1: It will crenate.

Explanation (copied verbatim from the MSA NMAT Reviewer in Biology): 

In a hypertonic environment, the cell has a lower concentration of solutes, and therefore it also has higher water potential than the surrounding extracellular fluid. Osmosis (the diffusion of water) causes a net movement of water out of the cell, causing the cytoplasm to decrease in volume. As a result, the cell shrinks (crenates) and forms abnormal notches around its edges. The effects of crenation are especially visible in red blood cells, or erythrocytes, as they become distorted in shape rather than maintaining the usual disc-like, dimpled shape that the red blood cell normally has.

Key Concepts:

Hypotonic solution has a lower concentration of solute than the concentration inside the cell which causes the cell to swell.

Isotonic solution has a concentration equal to the concentration inside the cell.

Perhaps I am simply not that smart. Such an explanation from the reviewer actually made me go "huh" and I had to go back and read it all over again.

Then, I decided to look it up on Wikipedia. The picture from Wikipedia (above) makes sense (after staring at it for a long time), but I don't think I'd be able to recall it with understanding (but I can certainly memorize it and stash it in my short-term photographic memory). The only time it made perfect sense to me was after a) I read the explanation on the reviewer multiple times, 2) looked up the photo on Wikipedia, and 3) clarified my understanding with my husband.

So, for me, it was a 3-step process just to understand and be able to explain a simple concept in Biology. Oh well, that is how my brain works. At least, I'm confident that I'll easily remember this concept the next time it comes up.

Maybe I should just take the test in April.