Dissection III: artifical insemination

Rather than complete another dissection, per say, we did embyonic development this week. A large portion of lab was spent peering through microscopes at 4,8,16,32, and 64 cell frog/chick embryos and sketching what we saw (not nearly as cool as it sounds, and it doesn't even sound all that cool).

BUT, we did get to artifically inseminate sea anenomes! This involved injected acid into the male and female sea anenomes to make them release their gametes. We put some eggs on a slide, then added some sperm (which we activated first) and peered down through 100X magnification as those hyperactive little buggers went worming their way in.

Now, for those of you who are not familiar with sea anenome fertilisation, once the sperm manage to fuse their plasma membrane with that of the egg, the cortical reaction takes place (otherwise known as the slow block to polyspermy). This reaction cultimates with the vitalline layer moving away from the plasma membrane (due to osmotic gradients caused by calcium induced vesicle fusion), a process you can actually see happening. Since I cannot photograph through the microscope, here's a drawing (done by someone in Wisconsin) of what happens: