What "I Love Lucy" can teach us about capillary nutrient exchange

During yesterday's review session we went over the circulatory system, an important part of which is the exchange of nutrients, gasses, and waste products between the blood and the body's tissues at the capillaries. Nutrients and gasses diffuse into the tissues to be used for cell proliferation, metabolism, and other things, and the waste products are taken up by the blood to be removed at the lungs or kidneys.

(I lost the source for this image. If it is yours, contact me and I'll credit you.)

We maximize nutrient exchange by increasing the surface area for diffusion (lots of tiny vessels instead of one big vessel) and slowing down the blood once it gets to the capillaries so it spends more time in the tissues. The professor for the class originally explained nutrient exchange as someone trying to pick candy off of a conveyor belt. We want the conveyor belt to move slowly so we can maximize the number of candies we can grab off of it before they pass us by. I thought this was a clever way to explain the concept, because my mind immediately went to the classic chocolate factory scene in I Love Lucy.

However... in the office hours and at the review session it became increasingly apparent to my co-TA and I that many of our students weren't getting the reference. And since they didn't get the reference, they didn't really understand the analogy. We told them to look it up on Youtube when they got home, but one student had his laptop in the room so he looked it up immediately. Other students watched it over his shoulder... began to laugh... and I could see the click happen. Suddenly they got it.

Seriously, what kind of person has never seen the chocolate factory episode of I Love Lucy? I didn't think there was a generation gap between my students and I, but now I'm starting to wonder.

Pictures and video for a Sunday afternoon.

Source. A reader pointed me to a second composite image of a "global human." It is "a composite itself from four composite of Northwest European, South & West Asian, East Asian and African faces..."

As I said in the comments at Razib's blog: "My, that is one attractive fellow. He looks decidedly Hispanic to me, which I suppose shouldn't be surprising since Hispanics are already highly mixed people with Asian, African, and European ancestry. However, if you squint, he can look a bit Indian (or Italian, or mulatto, or hapa, or…)." I think the thought exercise here is less what the guy actually looks like, but more what we as individuals see in him.

Source. To correct [people's misinterpretations about the relative size of Africa due to maps using the Mercator projection], Kai Krause has created this map and associated information to show that Africa's total area is almost the same as that of the United States, China, India, Japan and all of Europe combined.

I learned about the faults of Mercator projections when I was pretty young, although I can't remember where I learned it. I think it was something I saw on television. My young brain couldn't quite wrap itself around the geometry involved, but I got the major point. Many maps use a system that, instead of staying true to the curvature of the earth, lay things out in such a way that the lines of latitude and longitude make rectangles instead of curved lines. This is mainly for ship navigation and the like, but it has the unfortunate effect of exaggerating land masses at the poles and diminishing land masses near the equator, such as central America, Africa, and India. In the Mercator projection, Africa looks to be only slightly larger than Greenland! If you've ever looked at a globe (I had a globe when I was a kid, which helped me with the geometry of this issue a bit), you know that's definitely not true. The original blog post has more detailed info on Mercator projections if you're interested.

Source. Myotonia congenita, or congenital myotonia is a skeletal muscle-locking disorder. In affected individuals, when the muscles contract, they do not immediately relax again: for a short period the affected muscles stiffen. If the individuals are standing up, they'll fall over, as the kittens in the video do.

I felt bad watching this video. Every time a kitten would fall down, my immediate instinct was to laugh, but then I wanted to cry. I had a very conflicting experience to say the least. The blog post accompanying this video has a really great explanation of the physiology involved in the disease; I suggest you check that out as well.

Big cats + catnip = ???

This is awesome. Someone videotaped various big cats (not all of them are 'true' big cats, but whatever) reacting to a bag of catnip in their environments. Most of them just roll around a lot and bat at things that aren't there.

No news is good news?

I've been pretty quiet this week, mostly because I took your advice and started reading. Stephen King (yes, now you know I'm a fan of High Literature) has written about four novels since I stopped having time to read regularly back in college, and people keep buying them for me even though I don't have time for them. I finished one and now I'm halfway through another. K and I had a fantastic argument the other night about high vs. low art that stemmed from the fact that I was sitting around reading Stephen King all day. Frankly I don't care if King novels are low art, I enjoy them. They do something for me, and that's all that matters. Plus I'm very fond of the fact that his female protagonists are always every bit as well-developed and fleshed out as his male protagonists. Dude knows how to write women, and almost all of his books pass the Bechdel Test. I appreciate that.

I've veered away from the point, though, which is how I don't understand how people can read and write at the same time. I can't set aside a book and start writing about science because my brain is still in the book, you see. That's why my blogging has been so light. I do have a great post about emetophobia for next month's Carnal Carnival that I've been working on slowly, though.

Since it is Saturday, I am obligated to post at least one picture of a rodent. First, also from the link in my last post to the science dessert roundup is this mouse cake:

Now, here, have a chinchilla wearing a paper hat:

Video: counter-current multiplier

A former student of mine shared this wonderful little video with me at the end of summer session. Counter-current multiplication is the way the nephron reabsorbs Na+ ions and water in the loop of Henle to produce concentrated urine and minimize water loss. It is often a complex concept for students in my intro class to grasp (CB says it's the hardest concept in the class), but this video is great for breaking it down into the basics. I'm going to keep this link handy to show future students who are having trouble understanding.

Blood filtration and urine production

In other physiology news, there's a great post up at WhizBANG on how excess salt causes bloat.

Also, if you are an LGBT scientist, you may want to head over to Biochemist in Training and answer her questions about how to be a better ally.

King of the Lab!

Check out this tres cool fan video of my favorite television scientist, Jack Hodgins.

Some tunes for the morning.

Here, have some pretty music to brighten your morning.



The hook, loosely translated, means "the night is my blanket". I'm cranky because Advisor is out of town and he's making us go in his stead to some meeting with representatives that are trying to sell us some new -ography machine, but this music is making me feel better.