Virtual Cardiology Lab, EKG, Etc

Cow Heart

Over the past few weeks we have been learning about the heart and our cardiovascular system. This post is going to be combining several labs and a dissection. To start with we did a dissection of a cow, sheep, and pig heart. We cut down the middle of the heart and made it to where the ventricles and atrium's were visible on both sides. Then we started to take measurements of pretty much all of the main parts of the heart and found most of them to be relatively the same. The cow heart was pretty huge and dwarfed the sheep heart, which was mainly covered by fat. The heart to the left is a cow heart and was a really good example of how they showed all of the ventricles, atrium's, and the arteries and veins. So that is a pretty basic overview of what our lab was, the most consistent thing in our lab was that the left ventricle walls were the thickest in the heart. Here is a graph to show all 10 of the measurements we took on the three hearts.

Click on the Graph to Enlarge

Andrew

Andrew Reversed

The next lab we did was on our heart beat, pulse, and blood pressure. We experimented with the older equipment first to try and get this data, but found that neither of us were really good enough to listen for a heart beat with a stethoscope. So then we used the newer blood pressure cuffs that pretty much did all of the hard stuff for us and gave us our information. The graphs are our heart beat over a time span of 5 seconds. We found most of them to be relatively similar with the dips and jumps, also called (p,q,r,s,t). The graphs to the left are our data that we collected on a different pulse experiment. We actually didn't record any of our data on cuffs. But they probably would have showed the same relative heart beat as this graph does. To do this lab we hooked up to a machine with 3 wires going to us, red, green, and a black one that acted as a ground wire. When it says our name and then reversed at the end it is just when we switched the green and red wires around and gave us our heart beat upside down. The EKG, also known as an Electrocardiography machine gathers its data by monitoring the electrical activity of the heart over time. This is usually gathered by probes placed on the skin that picks up electrodes on the skin and amplifies them to a certain extent and thus gives us the EKG readings on the machine.

Daniel Reversed

Daniel

Brian

Brian Reversed

Lou Gehrig's Disease Research

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Leech Neurophysiology Lab

Purpose: The purpose of this lab was to attempt to identify the different types of cells that are located within the Ganglion of a leech.


Hypothesis: I predict that the different types of cells will have a larger reaction when stimulated by a harder object like the probe or forceps while having little reaction to a feather.


Materials: 

• Feather - Used to give the leech skin a very gentle touch stimulation.
• Probe - A blunt metal rod used to lift tissue, and to push the skin as a stimulus.
• Forceps - Used for very fine manipulations.
• Scissors - Angled dissecting scissors, used to cut the body wall open.
• Pins - Used for pinning tissue to a dissecting dish or board.
• Scalpel - For microsurgery, used to make incisions in the leech.
• Dissection Tray - The tray that the leech was pinned to.
• Leech Tank - Used to keep the leeches in a natural like environment.
• 20% Ethanol - Used to anesthetize the leech, more humane, it stops them from moving.
• Leech Tongs - Blunt tips so that the leech will not be harmed from picking it up.
• Dissection Microscope - Specifically designed for dissection and other micro-manipulations.
• Micro-manipulator - A device used to position the leech with sub-micrometer precision
• Oscilloscope - A sophisticated voltmeter.
• Leech - Medical leeches, 15-20cm long, 1-2cm wide

Procedure: First thing we had to do in this lab was to catch a leech from the tank and then anesthetize it and place it on the tray. Then we pinned it down, cut it down the middle, used forceps to tear the skin apart and then pinned the flaps to the tray. We then had to remove the innards with a probe so we could find the nerve cord which is encased in the ventral sinus. Then cut a window out of the ganglion under the dissection microscope, then cut a parallel section of the skin out and did the same with an ultra fine scalpel. Then used the micro-manipulator to stimulate the ganglion. Injected dye solutions into different spots and then used a UV switch to see where the dye had spread to. Then used an atlas to determine what type of cell we had stimulated.


Results: The results turned out pretty good overall. The atlas really helped to determine the types of cells we were probing, but some of them I still got wrong. The lab helped me understand the different types of cells a bit better.


Conclusions: The chart below shows that I was actually very wrong with my hypothesis. The 5 different types of cells found in the Ganglion all react differently to different types of stimulation.