This is fascinating guys and I'm going to put it into simple terms:
Blood flows through the arteries and veins at high speed. The speed is so immense in some areas that the blood cells appear as a blur to the naked eye. Imagine a hose pipe, and you turn the tap on fully at the connecting end. You get the idea...
However, what if certain cells need to proceed through the blood vessels at a slower speed?
Just think of the task at hand:
You have a hose pipe, with fast flowing water inside. There are elements in that water that you want to move across slowly - so how would you set about designing it?
- perhaps have something on the inner wall of the hosepipe that is able to attach to the desired element.
- the attachment shouldn't be too strong, because that would simply stop the element from flowing.
- the attachment shouldn't be too weak either, because then the element would fail to attach at all.
- so, we need a compromise between the two
- the attachment should be specific to the element you want to transverse slowly. otherwise, the hosepipe would clog up.
- you need to factor in the velocity, temperature, viscosity (thickness) of the fluid circulating the hosepipe amongst other things for the desired outcome.
However - this is a great simplification. to complicate things, What if you only want certain elements to transverse slowly at certain times and positions? In that case, the attachment will have to pop up on the inner wall of the hosepipe at certain times and positions, and go back in at times and locations you don't need them.
How do the attachments know when to pop up? well, you will need censors all around the hosepipe and relay mechanisms. Let's complicate things even further - what if you wan't those attached elements to leave the hosepipe at specific places?
What I've described above is a tiny fraction of what is going on in our veins on a daily basis.
watch this short (2 min 30 sec) clip. First, is a series of diagrams explaining what happens and then a video of it happening before your very eyes
The real life video is 1min onwards.
I've posted this mainly to tingle your senses with regards to science....and also, for you to be fascinated by Allah's artistry.
This post has been edited by YaNabi-Chemist: 17 December 2011 - 08:39 PM