Yesterday, in Physiology lab, I got to dissect a crab. This was utterly perverendus. We were mostly focusing on the nervous system, which means I only really looked at other stuff incidentally, but I still did. It also meant that the crab was still alive, since nervous systems deteriorate very fast in dead animals, and arthropods are very hard to kill quickly without obliterating the nervous system. This proves that my teacher has guts, given general opinion on things like that.
Anyway, at the start of class, they had crabs and crayfish on ice to slow down their metabolism and keep them from getting away. Everyone could chose either a crab or a crayfish to dissect. I, being me, would have liked to have done one of each, but there weren't enough beasties for people to do that.
I took a crab. He was a male lyre-crab with a body about the size of my palm. In dissecting a crab, the first step is to take off the carapace. You just get a good grip and pull it off. This breaks the optic nerves because the eyestalks are attached to the carapace, but I dissected the eyestalks separately so that was all right.
Once that was off, most of the internal organs were exposed. Specifically, I could see the heart, gills, and part of the hepatopancreas (which is a huge epic gland in arthropods which serves many different functions and takes up immense amounts of space), as well as all the little mouth parts in the head. Crabs have an open circulatory system, so everything is just sitting in a pool of hemolymph (whitish-clear arthropod blood) and the heart is just there on top of the other organs, keeping it stirred. It is white and beats visibly, which is very cool. The gills are like these cones made of wet ivory-colored fuzz, and they stick up from the sides of the rest of the body under the carapace. They were outside of where the carapace articulates with the rest of the exoskeleton, so are outside the open part and would have their hemolymph in blood vessels. The gills came out of holes in the exoskeleton above each leg and under the "eves" as it were of the carapace. The hepatopancreas was light brown and looked like a mass of tiny, stuck-together orzo pasta, more than anything else I can think of. I could see parts of it around the heart, but most of it was underneath. The mouth parts were like a lot of small legs with projections on them. They moved nearly nonstop.
I cut the gills out, and pulled the heart out with forceps. The crab displayed an impressive ability to survive without oxygen by continuing to move for most of the project after this. Under the gills, I could see the muscles of the legs. They were white, and looked like crab meat everywhere. I could see them move when the crab's legs moved. Under the heart, there were gonads and more hepatopancreas. The gonads looked like a tangled string with little rounded-cube things coming off of it. This was white, and white cloudiness which was almost certainly sperm came out of it when I poked it with forceps.
I pulled out the gonads and set them aside. The body cavity now seemed to be entirely full of hepatopancreas. I pulled this out bit by bit, and eventually exposed the gut. A crab's gut looks pretty simple from the outside, like an unelaborated tube, and I did not cut it open. The gut was entirely surrounded by hepatopancreas. I cut it out, and set it aside, and set about removing the rest of the hepatopancreas.
When I got it all out, the body cavity was empty and I could see the nervous system. Arthropods have a very cool nervous system, which is nothing like that of a vertebrate. They don't have a brain per se, their central nervous system consists of a nerve cord that runs along their ventral surface just under the exoskeleton, flanked by paired swellings called ganglia. The cord extends the length of the body, so in a crab it is pretty short. In a crab, the central nervous system and the major peripheral nerves form a slightly stretched sunburst shape in the bottom of the body cavity.
I poured out the hemolymph and rinsed the body cavity with artificial seawater (a lab-prepared solution with the same solute concentrations as seawater). The crab impressed me further by continuing to move. I could now clearly see the nervous system, since the cloudiness was gone. I wanted to look at the nervous system under the stereomicroscope, but the crab's exoskeleton was too tall. So I got some heavier scissors that were ok to cut chitin with, and cut off the ridge that had articulated with the carapace. My crab now fit on the stereomicroscope stage, so I put him there and looked inside him with magnification. Under the scope, i could see the individual ganglia, which just looked like bulges on the sides of a white fat rope. This is what formed the oval part of the sunburst. The peripheral nerves came each out of one ganglion. It was while I had him under the scope that my crab finally stopped moving.
The teacher came over, and she said I had dissected out my crab's nervous system beautifully, and she would like to try to mount it (on a slide for a regular microscope preparation). I said ok, and she tried to do so, but she broke the nerve cord, so that was too bad. Someone's crayfish's nerve cord did finally get mounted, though.
The last thing I did in lab was cut the crab's eyestalks in half, and look at the inside under the stereomicroscope. It's full of a nerve and some muscle bits, but there is also the sinus gland, a big (relatively) white lump that is the crab's "master gland," kind of like a vertebrate's pituitary, it regulates all the hormone production.
Anyway, this probably means I'm a sick, evil person, but I had great fun with this dissection. That is probably more than enough, however, of my spouting about the insides of a crab.

So. New topic. I don't know if anyone has noticed, but I have been absent from IM and suchlike yesterday and so far today. The reason for that is, I am doing catchup homework. I had issues at the end of last week, which I'd rather not go into (and would prefer if the one person reading this who knows what I'm talking about wouldn't either), which resulted in my accomplishing next to nothing for three days. I'm carrying 17 credit-hours, half of them upper-division, and a job, and trying to deal with my promise backlog. Accomplishing just north of zilch for three days is a Bad Idea in such a scenario, and so now I have homework backlog.
I have time to post this because I'm in class right now--Marine Biology, which is an easy lecture class and the teacher is talking about stuff I already know. It's really bad form to do homework for a different class in class, so I have sort-of-downtime.

In other news, there is now a sexy scanner at UAS. It's in the library in the media room, which has limited hours--10:00-17:00 weekdays, I think--but it's free for student use during that time. With this, I can give a list of things you can expect to see soon. I'll say for now in the unspecified near future, which probably means either when I'm caught up on homework or when I otherwise have downtime I can't use on it.

To be Posted Soon:
*Old drawings from my little sketchbook (already scanned, I just need to move the files around and post them)
*Crappy scraps from art class (just need to be scanned)
*Black-and-white version of the Flying Potato's fly dude (just needs to be scanned, he wants color but I'll do that LATER)
*Small picture of Professor David Falconer (one of the human OCs mentioned in the promise list, picture almost done)

My promise list for here is unchanged from [link] unfortunately.

And my sleep schedule is also unchanged from the last update at [link]

~Jag