In this lab three different hearts were dissected. We had a sheep heart (littles), a pig heart (middle sized), and a cow heart (biggest). While dissecting the hearts we were able to see and locate different parts of the heart that were not seen in all three. After cutting the heart open, we measured the main parts of the hearts. Down below are a few questions that I answered after completing this lab.
- After reviewing the artery and vein prepared slide, which blood vessel has the thicker walls? is there a possible reason for this, on the basis of blood vessel function? .. The right wall is thicker in all the hearts and I think this is because it has to be bigger due to the blood flowing in through the right atrium first. The wall has to be thicker to protect the vein (bigger vein).
- After viewing the cardiac muscle prepared slide, is cardiac muscle smooth or striated?……… ..The cardiac muscle in the heart is striated because it contracts to squeeze blood out and relaxes to let blood flow in. The heart is a muscle that never gets tired and never rests.
- After viewing the prepared slide of a coronary artery with atherosclerosis, what is the danger of having this artherosclerotic plaque on this particular artery? ……… .. The danger is that it will block the blood flow.
- How does the basic structure of the heart compare between the three heart specimens? ..Our heart is more like the pig heart because its the medium sized heart. The sheep heart is more the size of an infants heart and the cow heart is way to big to compare to a humans heart.
- a. What are some of the major differences you observed in the heart specimens? .. The smaller parts are located on the left side of the heart and the bigger are located on the right. .b.Can you think of any adaptive reasons for these differences? .. The fact that the blood flows in on the right side causes it to be bigger to take the great quantity in.
Inside the pig heart
The picture above is of a pig heart. This heart was the middle sized heart of the three dissected. These pictures also show us measuring the heart. This was the first heart dissected and I was able to locate pretty much every part of the heart.
Measurements are listed below for length otherwise stated.
- Aorta- 4cm
- Pulmonary Trunk- 3cm
- Left Atrium-4.5cm
- Left Ventricle- 5cm
- Left Outer Wall- 1.5cm
- Right Atrium- 4cm thick
- Right Ventricle- 3.5cm thick
- Right Outer Wall- 1.5cm
Inside of the sheep heart
The pictures above are of a sheep heart. The sheep heart was the littlest of all three hearts dissected. I had a little trouble trying to locate the different parts because everything was so tiny. Down below are the measurements in length otherwise stated.
- Aorta- 2.5cm
- Pulmonary Trunk- 3cm
- Left Atrium- 2cm
- Left Ventricle- 10cm
- Left Outer Wall- 1.5cm thick
- Right Atrium- 4cm
- Right Ventricle- 9cm
- Right Outer Wall- 2.0cm thick
Inside the cow heart
The pictures above are pictures of a cow heart. When dissecting the heart I found a lot of interest, considering the fact it's the biggest one to be dissected. I found it easier to locate the different parts of the heart because it was so big. Down below are measurements in length otherwise stated.
- Aorta- 7cm
- Pulmonary Trunk- 12cm
- Left Atrium- 7.5cm
- Left Ventricle- 11.5cm
- Left Outer Wall- 6.5cm thick
- Right Atrium- 7.5cm
- Right Ventricle- 11cm
- Right Outer Wall- 7.5 cm thick
The graph below shows the difference between a cow, pig, and a sheep heart's thickness of the outer wall. The bigger the heart, the thicker the outer wall. The right side as you can see will always be bigger due to thats the side the blood comes in, which makes the right atrium bigger, causing the wall to be thicker to protect it better. The bigger the animal (heart) the more blood that is flowing in, causing the wall to once again be bigger.
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