The power of Electrons… And a few electrolytes (Day 14)

Electron Microscope

My second Monday in vet school, we were told last week that this week in histology we’d be looking at Electron Microscopy which is a pretty big thing. I’d never seen an Electron Microscope before let alone learnt anything about it (apart from vague references). An electron Microscope is pretty powerful allowing you to see the different organelles within cells and maybe more importantly viruses which are too small to visualise otherwise.

The main lecture was on the cell structure and components which is pretty important and then after a couple of hours break it was time for practical. Something that still gets to me a little is seeing warning signs with symbols for death and yet not being able to read the text information which is kinda interesting. We get led into a prep room with a rather large sign like this, and loads of machinery and chemicals around.

The preparation for electron microscopy is different as it requires that the sections (or samples) of tissues to be examined be thinner (between 30nm – 60nm thick) which means damage is easier to do. Anyway samples are cleaned, chemically fixed and mounted in plastic to faciliate cutting. Now the actual cutting of sections is down by a machine called a ultramicrotome using a glass diamond blade under microscopic magnification. These samples are then mounted onto wire mesh grids which then can be examined under the electron microscope.

Now electron microscopy works by passing an electron beam through the sample at high temperature from an electron gun consisting of a cathode and anode before it goes through objectives and onto a recieving plate which converts the invisible electrons into a visual image for us humans. While being able to achieve incredible magnifcation the use of electrons mean that images from an electron microscope are in black and white. Just turning the microscope on takes several hours to warm it up (and eats a ton of electricity) however the university has two electron microscopes in working order that they purchased in 1980. I just need to find a reason to get to play with them myself 🙂

Electron Microscope
Electron Microscope

Arriving for Physiology later in the afternoon the lecture started of rather excitingly with electrolyte balances which is something I was looking forward to learning about. It rapidly changed focus however to another pretty common sense lecture sadly. The evening was then spent doing some revision for Genetics tommorow….

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