Sunday, May 24, 2009

Spider-Palm: Number 3

To recap: Parker is bit by the radioactive spider that is also a genetic hybrid of three different breeds of spider, one of which happens to be an excellent and prolific web-spinner. The venom, or some DNA from the spider's saliva, or something starts to do a number on Parker and his immune system. He goes to bed with flu like symptoms(1).

During the night, fibroblasts and myoblasts(2) migrate to Parker's palms because he has been chronically abrading them from some unkown activity, which he may have been performing that night, despite his illness. The fibroblasts form a bursa in each palm, full of synovial fluid that is altered by the spider's venom, or DNA, so that it dehydrates quickly, is adhesive instead of slimy, and has incredible tensile qualities.

Myoblast (Looks a little like a fibroblast, doesn't it?)

Now, here is my more fanciful stretch of the imagination(3): myoblasts, found in the repairing injured tissue of Parker's inflamed palm, infuse and strengthen the structure of the bursa. Normally they would weaken or recede after repair is complete. These cells, thanks to the spider DNA, become incredibly strong smooth muscle cells, much like the cells that line one's intestine(4). Come to think of it, since Parker's skeletal muscle is transformed into incredibly strong tissue, it stands to reason that the smooth muscle in his gut (and everywhere else) is now super-strong as well.

Smooth muscle contracts with a wave-like actions known as peristalsis. This coordinated rippling in the gut gets your food through your digestive tract and excreted through your other end(5).

(The principle is the same)

Parker aims his wrist at a distant object, flexes his third and fourth fingers, pressing into his newly formed bursa as he hyperextends his wrist to increase pressure on the fluid deep within the new sac of palmar fascia. The smooth muscle around the bursa contracts with peristaltic Spidey-strength and propels a mighty stream of whitish sticky stuff out his... wait a minute...

Wrist technique

My God!!! Parker has no hole! (In his wrist.) He has to have a hole there or nothing is going to come out. And how can Parker release a precise stream of fluid propelled for tens of yards on muscle power alone without a sphincter to control that mighty stream?

Only a scar

At his wrist we see a shot of a star-shaped scar-like structure, but there is no opening in his skin. there has to be a flap, or slit in the skin, or a miniature anus, or something. i understand that the producers might have felt that showing a puckered little sphincter or even a urethra-like opening on Parker's wrists might be a mood killer, but authenticity is important!

We're supposed to believe that these super-spider-DNA-enhanced-bursae with peristaltic sphincter propulsion just magically transport this sticky fluid through his palms and onto buildings without an opening in his skin? If there's no hole there, then how is any of this believable? My day has been ruined! Now I feel foolish analyzing this whole scenario, which obviously can't occur due to a simple lack of aperture!

Next, they'll be trying to get us to suspend disbelief as we watch some guy hook himself up to a robot with tentacles, that takes over his mind during a lab accident.

Speaking of robots, well robots and cyborgs, next time we will look at a few moments from the new Terminator movie.

1. For more about flu like symptoms you can see Spidey Palm 1 (5/04/09). For you trivia buffs, Star Trek also relies on flu like symptoms for a small bit of plot (5/10/09).
2. Myoblasts are the cells from which all three types of muscle tissue develops, in utero. A type of myoblast helps repair injured tissues in adults. The textbook Human Anatomy and Physiology by Marieb and Hoehn, 7th Edition, 2007 from Pearson Benjamin Cummins, pp. 316-317, has an interesting explanation of myoblasts and what they do.
3. As if the rest of this was "sound science."
4. There are three kinds of muscle tissue: cardiac, found in (you guessed it!) the heart; smooth, found in glands and tubular organs; and skeletal, attaching mostly to bone. This is the type of muscle we use to move around with, and we eat as steak.
5. Anus. There. I said it. You have an anus, as do I, as does Peter Parker, and Mary Jane Watson. Plural of anus can be either anuses or anii.

Thursday, May 14, 2009

Star Date: 2253.04

I saw Star Trek last night. Great movie! It has lots of action and aesthetically pleasing blood, which are two of my main priorities for this type of film.

Why am I interrupting the Spider-Man posts to talk about Star Trek? Well, dammit, Jim! This is important, man! It seemed like a good idea to go over a couple medical points that stood out. They were remarkable enough for me to try and take a couple notes in a dark theater, but shouldn't interfere with your enjoyment of the movie, in the least. Minor spoilers (for the extremely sensitive) follow.

Boy Spock: This is not the shot in discussion. I couldn't find that one on the IMDB

There is so much that is good about this movie, I don't want you to think I didn't enjoy it. The baby delivery scene is a hoot! But I did notice something that seemed like a bit of an oversight in a later shot that could have been corrected easily(1).

What was the problem? Boy Spock's ears. We see young Spock (Jacob Kogan), his lip split from a fight and oozing green blood, as he sits in front of a window, providing a flattering, glowing back light. He is impish and cute and has the look of an emotionless Vulcan school boy who knows he's been bad. The light from the window gently enfolds him and gives his little pointy ears a glowing pink tint.

This is where the record scratch sound that implies, "What the f---!" would come in. Don't get me wrong, the ear-glow is good. They make the prosthetic pointy ear (I assume it's a prosthetic) match its glow to Kogan's real ear, creating a seamless piece. But ears glow pink when light shines through them because of the red blood in the capillary beds of the ears.

I'm okay with green blood oozing from cute Vulcan red lips, this is art after all, but they missed an opportunity for a little finesse when they didn't make those ears glow green. The shot only lasts a few seconds. How hard can that be?

I just wanted to point out the scene where McCoy (Carl Urban) gives Kirk (Chris Pine) a vaccine so that Kirk will develop symptoms of illness and be taken on the Enterprise. He develops flu-like symptoms such as headache, nausea, fatigue, fever, etc. This is true of many vaccines for many diseases. They also added some colorful symptoms like blindness in the left eye. This sequence is not too far off base, but extremely sped up to keep the plot moving. An injection may be able to get into your bloodstream in seconds, but it is still going to take your body hours or days to react to the pathogens in the vaccine(2).

Kirk has an allergic reaction to the shot. This is a Type I hypersensitivity reaction. His hands and tongue swell. He's lucky he can still breathe. People who get swollen tongues often get swollen lips, and not like they've had a bit too much collagen injected there, either. Think of having a child's football attached to your face. This doesn't happen to Kirk, only his hands are disfigured by swelling, and he can't talk. It may be the severest reaction McCoy has seen to the vaccine, but Kirk is lucky nonetheless.

McCoy orders something that sounds like "cortisone" to be given to Kirk. Epinephrine-like drugs will probably still be the drug of choice in the future over a cortisone-like drug. Epi-pens are used for these types of emergencies, currently. But what do I know, I'm not a pharmacologist by any stretch of the imagination. That stuff is hard.

Vulcan nerve pinch: note the third and fourth finger placement over the area of the right brachial plexus as it emerges from the scalenes.

This Vulcan nerve pinch thing cracks me up. As a massage therapist I can put people into exquisite pain by squeezing the upper trapezius or anterior and middle scalene muscles, but I have yet to be able to render a patient unconscious. Lord knows I've tried.

Anatomically speaking, the only bundle of nerves in the area is the brachial plexus, which is composed of nerves leaving the vertebrae of the neck. They pass between the two scalenes mentioned above, and then form a number of nerves that innervate the arm and hand.

Squeezing the brachial plexus with the Vulcan nerve pinch won't effect the brain, but could cause someone to develop a bad case of Carpal Tunnel Syndrome, or Thoracic Outlet Syndrome, or in extreme cases paralysis of the upper extremity.

This being said, I assume the nerve pinch is only doable by Vulcans because it involves some sort of telepathy, or mind-meldy thing to make it work.

One last thing: Spock (Zachary Quinto) tries to strangle Kirk. When Spock releases him, Kirk has ruddy finger marks on his neck. Nice touch!

Next time we continue our discussion of fibroblasts and Spider-Man's biological web spinning abilities... I swear it!

1. If you have an extra million dollars lying around for things like this.
2. For more on flu-like symptoms, go to the first Spider-Man post.

Sunday, May 10, 2009

Spider-Palm: Number 2

Fibroblasts? Really, fibroblasts as the key to engineering Spider-Man's web-squirting palms? Yes, fibroblasts. They even sound cool.

What are fibroblasts? They're cells that build connective tissue. They hang out in fascia, tendons, joint capsules, and other connective tissues and produce tough bundles of fibers made out of collagen. In a way, you could say that fibroblasts can spin a web, any size(1)!

When you tear a muscle or get tendinitis, or bruise or cut yourself, an inflammatory reaction results which helps to promote a series of events that will help repair dead or damaged tissues(2). Fibroblasts and some special types of muscle cells will move into the area to repair the damaged tissue. This repair process usually results in a scar.

Sometimes if a tendon, or the superficial connective tissue below the skin, becomes chronically stressed, abraded, and inflamed, fibroblasts will migrate to the area and begin to form a sack of connective tissue called a bursa, to try and cushion the area being stressed.

What does a knee have to do with bursae? They're everywhere, that's what. If you want to experience a bursa first hand, pinch up the skin over your knee cap and roll it between your fingers. Feel how slippery it is inside? That's because there's a (pre-patellar) bursa there and you are rolling its slimy surfaces across one another.

Bursae(3) are normal parts of the musculoskeletal system. They are connective tissue sacks full of slimy synovial fluid(4). They are usually located between a tendon and a bone and provide cushioning to protect the tendon and its muscle from injury. The German word for bursa is schleimbeutel, which means "slime bag," which is exactly what they are. I love German!

As I said, you can grow extra bursae if you're chronically irritating an area. So... what kind of activity could a teenage male be engaged in on a regular basis that would create so much friction and abrasion of the palms, that his body would need to alter his palmar structure to protect it? Hmmmmm... it would have to be some kind of grasping, or rubbing, repetitive activity, performed regularly over weeks or months. I'm sure I can't think of anything.

Next time I'll tie these parts together to describe Parker's incredible transformation...

1. Is anyone keeping track of how many times I have recycled this joke?
2. For you trivia buffs, this inflammatory reaction is pretty much the same type of thing that I mentioned in the posts about Face/Off. The context is slightly different, but once again, we see that the body has only a limited number of ways to respond to trouble, and inflammation is a common response. Inflammation is also the reaction that would cause those hives Peter was experiencing in my last post.
3. Bursa is singular, bursae (pronounced bursay, or bursee, depending on who's arguing the loudest) is plural.
4. Synovial fluid is a slimy substance with the consistency of egg whites. It's just like that, really. I dissected a cadaver once and there was still synovial fluid in his knee. It's very clingy. Ick! Synovial fluid is secreted by a membrane called the (you guessed it!) synovial membrane, which lines the bursa, and also lines the inside of your joint capsules. The stuff helps lubricate surfaces to reduce wear and tear as they slide across one another.

Monday, May 4, 2009

Spider-Palm: Number 1

One of my anatomy students has asked me to explain Spider-Man's web squirting ability in one of my posts. How could I resist the opportunity to make jokes about the sticky palms of teenage males? I couldn't. I didn't even try. But I will try to keep myself in check and only crack wise at every fifth opportunity.

In both the comic and the movie (starring Toby Maguire as Peter Parker and directed by Sam Raimi), Peter is bitten by a genetically altered radioactive spider whose venom transforms Parker physically into the Spider-Man.

As we all know, Spider-Man's biological web making skills are not an issue in the comic book because although Parker was bitten by a spider, he devised a mechanical device that he straps to his wrist, by which to spin a web (any size!)

Steve Ditko drawing from Amazing Fantasy 15
(Being married to a cartoonist comes in handy!)

For this particular film, my challenge is to support the story by explaning the physiology behind the physical metamorphosis that Parker undergoes in teh movie. Let's start with his reaction to the spider's bit.

Here's a riddle: What do you get when you cross malaria with measles, Lyme disease, AIDS, and the flu? The answer is: Flu like symptoms! Ha! Ha!

Whenever your body is invaded by a pathogen, you fight it off in the best way you know how, which often means an elevated body temperature (fever) and some other events that help to boost up your immune system. The result is headache, malaise, muscle aches, fatigue, chills, etc. It doesn't matter whether the pathogen is something that will kill you or just make you miserable for a week, you body will usually respond the same way to practically anything.

So Parker gets bit by the spider and what happens? He ends up in bed with flu like symptoms or something. He sweats, he's shaky, a little delirious, probably has a headache, etc.

Flu like symptoms
He also develops some lesions on his skin. Some diseases, like chicken pox or measles cause skin lesions, but can skin eruptions be the result of insect bites? Sure, a common disease caused by an insect bite is Lyme disease(1), which produces a bulls-eye rash at the site of the bite. Come to think of it, Parker gets a tiny bulls-eye rash at the bite, and skin lesions as well. Maybe the spider is also a vector for a radioactive bacteria? No... that's crazy.

Parker gets a bunch of other welts over his forearms and not just at the site of the sting. commonly, one would only find a skin lesion at the area of the bite. Perhaps Parker is having an allergic reaction(2) to the radioactive spider venom. As far as make up goes, those hives (urticaria) are good and pronounced, but personally I'd like to see them pinker.

The welts work for allergic urticaria as is, but pink or ruddy skin indicates a perfusion of blood in the tissues' capillary beds. If Parker is undergoing a physical metamorphosis, that process is going to require a lot of oxygen, nutrients, and waste removal, all of which would happen via the blood. A little more rouge would boost authenticity.

Parker's flu like symptoms are not only a sign of his body's attempts to combat the spider's venom, but also a sign of his heightened metabolism, as his cells transform themselves and reorganize his body into that of a super-strong creature able to squirt adhesive fluid from more than the usual places.

How did he do it? How did his body grow a bunch of liquid web that would propel itself out of his wrists? Here's the magic cell that I say did most of the work...

The amazing fibroblast!

For more amazing adventures, stay tuned for the next post!

1. Lyme disease is caused by a tick that carries bacteria in its saliva. The tick is a vector for disease, meaning it does not cause the disease itself, it carries the organism that causes it in its mouth. The bacteria are then transmitted to a new host and the host, if it's a person, develops Lyme Dissease.
2. Allergies to many stings are a Type I hypersensitivity reaction. An allergic victim of a sting can experience a severe reaction at the site of the bite, but also in other areas, such as the airway. Hives and swelling of the respiratory passages are common, and if severe enough can lead to death. It's possible that Parker is having a milder allergic reaction, although the welts would probably happen before he could get home. What an embarrassment! To be all welted up on a school bus, eyes watering, itching like crazy, wheezing, etc. and under the gaze of the girl you have a crush on, Mary Jane Watson (Kirsten Dunst)