- The pericardium is the sac outside the heart that connects the heart to the body and protects the heart; it secretes a fluid to lubricate the heart for movement.
Q2: Observe the blood vessels connecting to the heart. How do arteries differ from veins in their structure?
- Arteries differ from veins because they have thicker walls and do not have skeletal muscles to aid the process of "milking", which veins do. Veins are surrounded by skeletal muscles that help push blood through the veins against gravity. Furthermore, arteries have elastic and contractile layers in their walls; the elastic layer expands when the heart contracts and recoils when the heart relaxes, and the contractile layer is smooth muscle that causes vasodilation or vasoconstriction.
Q3: Place your finger inside the auricle. What function do you think the auricle serves?
- The auricles are wrinkled pouches on each atrium, and they each slightly increase the amount of blood that each atrium can hold.
Q4: Observe the external structures of the atria and ventricles. What differences do you observe?
- The ventricles are significantly larger than the atria, most likely because they have to pump blood to arteries that go to the rest of the body, so there needs to be space for a larger volume of blood.
Q6: Draw a picture of the tricuspid valve, including chordae tendinae and the papillary muscle.
Q7: Why is the "anchoring" of the heart valves by the chordate tendinae and the papillary muscle important to heart function?
- The "anchoring" of the heart valves by the chordae tendinae and the papillary muscle is important to heart function because these two structures help the valves function and open to allow blood to flow in from the atrium to the ventricles. If the chordae tendinae and the papillary muscle were not attached to the heart, the valves would not be able to function properly.
Q8: Using pictures and/or words, describe what you see.
- I see the bicuspid valve in between the right atrium and right ventricle, which were smaller than I expected. There are two clear flaps/cusps with the chordae tendinae attached to them, which are also attached to papillary muscles that stick out from the walls of the chambers of the heart.
Q9: What is the function of the semi-lunar valves?
- The semi-lunar valves prevent arterial blood from re-entering the heart, so it continues to be pumped around the body.
Q10: Valvular heart disease is when one of more heart valves does not work properly. Improperly functioning heart valves can lead to regurgitation, which is the backflow of blood through a leaky valve. Ultimately this can lead to congestive heart failure, a condition that can be life threatening.
a. If the valve disease occurs on the right side of the heart, it results in swelling in the feet and ankles. Why might this happen?
- This might happen because a valve malfunction may cause blood to back up in other parts of the body. This may results in fluid buildup and cause swollen hands, wrists, feet, and ankles.
b. If the valve disease occurs on the left side of the heart, what complications would you expect to see?
- I would expect to see complications in the lungs, because the left side of the heart deals with the blood that is delivered to the lungs; there may be fluid buildup in the lungs.
Q11: Using pictures and/or words describe what you see.
- I see the bicuspid valve, which leads into the right ventricle. Then, the right ventricle curves up and I see the aortic semilunar valve, which has 3 cusps and leads into the aorta. I also see the coronary arteries on the anterior surface of the heart, since they are the main arteries that supply blood to the heart itself.
Q12: Describe how the left and right sides of the heart differ from each other.
- The left and the right sides of the heart differ from each other because the left side of the heart deals with oxygenated blood and the right side of the heart deals with deoxygenated blood. Furthermore, the left side also delivers blood through the aorta to the rest of the body, and the right side delivers blood through the pulmonary trunk to the lungs.
Q13: Draw and label all structures visible in the interior of the cross-section.
Link to our sheep heart dissection: https://www.youtube.com/watch?v=D5BNrrg4xrM
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