3 medical concepts I love to explain

I have spent a good portion of my life teaching in one way or another, so it is unsurprising that I love teaching things to my patients. When I can take a medical concept and make it easy to understand, I feel so happy!

And I really love it if this understanding has the potential to lead to better patient outcomes.

A lot of you enjoyed the post where I wrote about wellness products that are a waste of money. And since, like my patients, all of you have bodies, I thought you might enjoy three of my favorite little educational topics too. 😉 

Note: I promise this is not going to be really gross; it’ll be along the lines of my “your red blood cells are like a little bus with four oxygen seats” analogy. So, if you were ok with that, you should be ok with this post, and it’s safe to keep reading. 

1. Why antibiotics do not work on viruses

Most bacteria have cell walls, which basically serve to hold all the bacterial components together. 

Human cells do not have cell walls; we have cell membranes instead. 

Most antibiotics work by basically attacking cell walls and poking holes in them. This renders the bacteria useless because all of their components leak out, leaving what amounts to a deflated bacteria balloon.

Happily, since we don’t have cell walls, the antibiotics cannot poke holes in our bodily cells! Our cells are safe; the bacterial cells are not.*

Know what doesn’t have a cell wall? VIRUSES. 

And this is why antibiotics are powerless against viruses. Antibiotics are awesome at attacking cell walls, but viruses have no cell walls to attack; they just have a protein coating.

Ergo, antibiotics are not gonna help.

When I learned this in microbiology, it felt like such a light-bulb moment. I had always heard that antibiotics don’t kill viruses, but until then, I hadn’t understood why.

And I love to understand why. 

*A relevant thought: Ideally, we want to use treatments that will fix the disease but will not also destroy the rest of the body in the process. Antibiotics are a nice example of that: they kill bacterial cells but not human cells. Continuing this train of thought, I started to type about why what works in a petri dish does not always work/is not always safe in the human body, but that might be a topic for another post.

2. Don’t leave the strongest soldiers! (aka “why you need to finish your antibiotics”)

When you have a bacterial infection and you take antibiotics, they do a lot of their work right off the bat, which is why you feel better pretty quickly.

(I imagine the antibiotics floating around the body, going, “Pop! Pop! Pop!” as they poke holes in the bacterial cell walls. This is probably definitely not what actually happens.)

Not all the bacteria get taken down right away; there are some strong bacterial enemy soldiers who manage to hang on for a while, even after the weaker bacteria have succumbed to the cell-wall-poking. 

If you quit taking your antibiotics a few days before you’re supposed to, you have killed off the weakest bacteria while leaving the strongest ones to survive (and replicate). 

And replicate is what they will try to do. If they’re successful at regrouping and rebuilding, then you’ll have an infection full of these strongest soldiers, which you’ve probably heard of: antibiotic-resistant bacteria. And these guys are harder to treat! 

So, this is why your doctors are always telling you to please finish your antibiotics even if you start to feel better. 🙂

Fact check me here: Johns Hopkins article on antibiotics

3. How to get blood back to your heart

Our bodies have a pump (the heart, obviously!) that works to send oxygenated blood away from the heart through our arteries and out to the rest of the body.

But we do not have a dedicated pump to send our deoxygenated blood through our veins, back to the heart.

Gravity helps us with some of this, particularly in our upper body. But something else also helps: muscles! As we contract our muscles, they put pressure on our veins, which pushes blood through them.

Our veins have these nifty little one-way valves that keep blood from flowing backward, which means the repeated pressure from our muscles pushes the blood progressively toward the heart. 

If you have a typical level of mobility, you walk around during the day and your muscles squeeze enough to keep your blood moving on back to the heart.

But…if you are immobile in the hospital, or are on a long car ride or airplane ride, you are not moving those leg muscles, which means blood can hang out in the veins for too long.

And blood that is still for too long can form a clot, which is bad news (see this Mayo Clinic article).

That’s why we use sequential compression devices (SCDs) in the hospital (basically intermittent leg massagers); they’re like an external muscle pushing on those veins. 

It’s also why we try to get patients up and moving as much as possible! 

Obviously, most of us do not have access to an SCD machine, but if you can stand up and walk around a bit when you’ve been sitting for a while, that will help.

Or if you can’t stand up, you can do ankle rotations; that motion engages your calf muscles, which means you’ll help your blood to get moving. 🙂

Fact check me here: Anatomy and Physiology textbook  

How many of these did you already know?

(I personally learned about all of them in nursing school/prereqs!)

P.S. I have other medical tidbits I love to talk about too, so if you want this to be an occasional series, let me know, and I can keep a running list as I think of topics. 🙂