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)

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