Biology: Beyond VCE question thread (for questions outside the course)

[vox nihili]

Hi everyone!

I've noticed that we get a lot of questions on the question thread that don't relate particularly well to the VCE course. That's absolutely awesome! It's really great that you're engaging with the topics so much that you're left really curious about the information that the VCE course doesn't provide. For some on the thread, however, it may be a little intimidating to see people talking about stuff that they haven't seen before, because they think they might need to learn that.

As such, we now have a thread to indulge our curiosities and ask anything that's outside of the VCE course! Naturally, we can't promise you'll necessarily get an answer, but it will be a really good opportunity to think about your science a little more deeply and perhaps fill in some of the gaps you're dying to know about.


Disclaimer: you should always focus first and foremost on what you learn in VCE and use the knowledge you learn there to respond to any questions set by VCAA. There are no extra marks for showing off extra knowledge!!

[Calebark]

This question is probably a bit silly, but I don't know where else to ask.

Say I'm getting blood taken, and the phlebotomist/nurse/doctor slaps or rubs a vein, is this to disturb the mast cells to release histamine so local vasodilation occurs and it's easier to actually hit the vein?

[vox nihili]

This question is probably a bit silly, but I don't know where else to ask.

Say I'm getting blood taken, and the phlebotomist/nurse/doctor slaps or rubs a vein, is this to disturb the mast cells to release histamine so local vasodilation occurs and it's easier to actually hit the vein?

Really awesome question, and good thinking!

You're actually pretty close. There probably is actually a degree of mast cell disruption (one of the ways mast cells can be activated is via trauma like that), but my understanding is the major reason is that by slapping the vein you actually disrupt some of the cells lining the vessel, such that they release a vasodilator called nitrous oxide (yep, NOS).