Tuesday, November 16, 2010

Dissection: Equine Head

Did another equine dissection today ... the head.

We got in and there were heads on the tabled cut off at the top of the head and the ears had already been cut off.
*rank photo warning* ... just incase! ;)
The horses weren't killed for the practical, they are from ill horses which have been put down etc ... people do ask - just saying 'cos people can get stressed/upset by it!
Started off with the head in the tray:

Started off by cutting the skin from the top of the head, right down the nose to get the skin off, slowly cut it off, around the eyes,  turned it upside down and got the skin off in one piece.

Had a look at the muscles, cut a few off to look at them + compare the different ones
... the big one (masseter) is for munching side to side and the smaller one on the right is the temporalis muscles for biting the jaw shut.
Surprised me that the temporalis were so much smaller esp when you think about how hard they can bite!

We had a look at the horses teeth and guessed it was about 2 years old from the angle they meet, how worn down they were and from the lines and stars on the teeth.

Next had a look at the ear and Becky cut through it to get into the inner ear and I around the eye socket and got the eye out. We saw all the muscles and ligaments around the eye and saw the optic nerve - a little white nerve coming out the back. I cut away everything around it so we just the the eyeball and cut it in hald; was full of a clear liquid with bits of black in it, then there was a lump that was like yellow jelly, and a clear sphere in the middle like one of those bath beads - the lens! 8) If you touched the inside the black/blue lining was soo delicate, literally just fell apart..

We cut the top jaw in half with a hack saw so we could see inside the nasal cavities, have a better look at the teeth, pallet etc.
The pallet was actually soft and a bit rubbery, not like the roof of our mouthes ... can also see the 'stars' in the bottom of the teeth.

Next cut open the top of the skull and got the brain out!!
It was so weird to see what you typically expect from cartoons.
It literally came apart as you held it - pulled the 2 hemispheres apart. It was really soft, as if it was made out of creme cheese!! Soo amazing that people can do brain surgery on something so delicate as that.
Cut one of the hemispheres in half to have a look inside:

I thought it was all really interesting and got really stuck in!

Was the best practical and dissection we've done, although some people were a bit squeamish about it - I could have cut away and dissected it all for hours though! :P


lifeonplanetchicken said...

That's great Lewis, well done. Very interesting.

WrittleStudent said...

Woah, Lewis this is actually amazing. I'm currently doing Animal Management at writtle college, of course no where near the standard you're at! But wow, honestly think this blog is the only thing that's getting me through my biology assignments!

LWescott said...

Ahh thats really cool - hope you get through the assignments :)

Should probably blog more about other dissections and assignments we've done 'cos its good to look back and hopefully help people - will put the reproductive one up now!