Heart Dissection

Well, I did it...I cut open a cow's heart. The original plan was to dissect a pig's heart but after many, many phone calls and one poor excuse for a specimen...I finally got my hands on a heart.

So this is the story...

It took me a while to find the pig heart, then when I did get one the butcher had "trimmed" it and cut off the entire top half, right from the cuspid valves up...gone...no aorta, no pulmonary trunk, nothing...AND he cut it up into sections.

I tried to do what I needed to do for the dissection but there was nothing to look at...well, except for the flaps of the cuspid valves, the chordae tendoneae and the oblique groove.

So I searched for over a week for another and had no luck until I found an abattoir outside of town that was just in the middle of doing some beef. The butcher saved me a heart with all the important stuff still on but it is HUGE! (...and I'm NOT kidding...)

When the butcher first brought it out to show it to me I said, "it's so BIG!" He replied with, "big animal...big heart." I had to laugh!

Check out the size of this heart! Those are MY hands holding it!

Oh, and by the way, that white stuff all around the top of the heart...it looks like fat but it is hard like articular cartilage...I'm not sure if it was like that when the cow was alive but I can't imagine how it could have been! It was hard and sounded like wood when I knocked on it! Very strange!

Here I am pointing to where the two ventricles of the heart are. If you look just to the right of my left finger there is a hole where the butcher must have nicked the heart. Just above that is a clear view of the oblique groove, where you can see the main coronary vein.

(...yep, it is FULL of blood...)

Here you can see one of the "flaps" that look like dog ears. They are called auricles and they are the top portion of the atrial cavities...located directly below.

This is where it got really tricky...I found what I am pretty sure is the aorta but I could not, for the life of me, find the SVC, the IVC, the pulmonary veins or the pulmonary trunk. The butcher may have cut them off. I guess it's possible as this vessel was also very short, but I didn't see them so rather than stress over it, I moved on.

Here we see the coronary sinus and if you look close enough (and know what you are looking for) you can see the coronary veins. Both my son and I thought this was pretty cool.

Here we were just marvelling at the tissue that made up the vessels. It looked like white foam (like the stuff you pack breakables in) but it felt more like rubber. It was very strange. My son couldn't keep his fingers out of there!

This is an excellent view of the chordae tendoneae and the flaps of the bicuspid or mitral valve on the left side of the heart.

Check out how thick that heart muscle is! The left side of the heart needs to have thicker muscle to provide the strength and pressure required to pump blood to the peripheral vessels of the body. It is just amazing to me the way we were designed!

I'm pretty sure that these were pulmonary veins...I could find them from the inside but not from the outside! I couldn't get my finger into them so I couldn't "follow" them to the other side.

Okay, so this is where I started to feel sick to my stomach. The smell was getting to me and I had to touch a really gross, stringy blood clot. Kris thought it was very cool until he saw me turning green...then I think he thought it was even cooler!

This view is from the right side of the heart. Note how much thinner the muscle wall is on this side. When pumping our blood to the lungs, the heart does not use the same amount of force that is required to pump to the body...if it did it would cause the lungs to explode. I read in my text that the muscle of the left side of the heart is so strong that it could pump our blood 30 feet!

And finally, this is Kristian...my younger son and "autopsy" assistant. Once I was finished he started hacking away at the heart...he wanted to see all sorts of things...like what it felt like to cut it with sissors and how it looked to force the blood out of the veins and into the coronary sinus....What a kid! He said he'd like to "operate" on a pig's brain next! I told him to wait until next semester and we'll see!

I must note that, no matter how much easier it may be to get a cow's heart in place of a pig's heart, I suggest against it. There are some differences and it is harder to find the important stuff. I think this is partly due to the size of the specimen. It was so big that it made it awkward to work with and difficult to handle.

I am happy to have had the opportunity to experience the dissection of a heart. It was fascinating to imagine it pumping. I look forward to next semester when I have the opportunity to do this again! I wonder what it will be then....a brain? Hmmmmm.....

Long Bone Dissection

This posting is a feature of my experience of dissecting a pork leg bone. I was very fortunate to have a "crew" of extremely interested assistants! They included:

My brother Brad Rix.

Brad is a recent graduate of the PCP program at SIAST.

He is also a new hire at Backlins Ambulance in Moosomin.

My boys, Nathanael (12 years old) and Kristian (11 years old)...

These two are future surgeons, I'm certain of it! ;)

As excited as I was about this dissection, I was surprized at the fact that once I had identified all the parts of the bone and the knee joint there wasn't much else to do except scrape the marrow out of the middle and search for other interesting things like lymph nodes!

Either way, my two sons had a blast with it! They were right in there like dirty shirts...with the gloves and the little poker thingy and the scalpel...helping me to identify the different parts and testing my knowledge by asking the names and functions of the parts as we identified them. One of my boys was even my photographer! It was especially amusing that my brother had Nat and Kris referring to the event as "the autopsy"!

Anyway, here is my photo "album" of the Long Bone Dissection...

This is the very first glimpse of the inside of the leg bones of a pig...my boys were just a little grossed out by this initially, but they adjusted quickly!

This photo features the periosteum. This is the protective outer covering of the bone and it is made of dense connective tissue.

This is one epiphysis of the femur, the ball of the "ball and socket" joint. It is covered in hyaline cartilage which, when on the end of a bone, is referred to as "articular cartilage" and its purpose is to reduce friction in joints.

This is a clearer view of the articular cartilage and the fluid filled sacs called bursae, lined with a synovial membrane that encapsules the joint. Unfortunately the photo is not clear enough to make out the synovial fluid that was left in the joint.

If you look closely you can see what was left of the sticky, gooey synovial fluid between my fingers. This really got Nat...he said he thought he'd throw up! Of course he immediately started to ask if he could touch it too! Boys...I tell ya!

Between the bones of this knee joint you can see a semilunar cartilage disk (a.k.a. flattened fibrocartilage pad). This is called Menisci. Its purpose is to be a shock absorber between the bones during movement.

The line that I am pointing to is called the epiphyseal disk or growth plate. It is a band of cartilage where the bone grows in length. It divides the diaphysis from the epiphyses. (You can also see the patella on the left of the photo.)

Some ligaments...

Although this was intended to be a photo of ligaments it is actually a very clear image of the articular cartilage and the spongy or cancellous bone that fills the epiphyses.

This is a vein. It is being held open by the pointer in this photo because veins collapse without blood flowing through them.

This is some of the yellow marrow. As in the WebCT video, it appears to have been bled into.

I cleared out a portion of the bone so that we could really see what the inside of the medullary cavity looked like. It was very different from the spongy bone of the epiphyses. My boys thought the compact bone tube was very wierd. It is interesting to learn how a hollow tube could maintain such strength. It reminded me of the WebCT video where they tested to see what would withstand more pressure and the hollow tube surpassed the solid one.




These last two photos are of what we suspected may have been lymph nodes, though we had no way of confirming this. We searched the specimen for quite some time, in hopes of finding some nodes but other than these "bubbles" we found nothing.

I found this lab activity to be very enlightening and extremely valuable in my understanding of the skeletal aspect of our bodies as well as the production of blood. I found it fascinating to learn that bones are not just inanimate solid pieces of "stuff". That they are active living cells.