Heart Dissection

Compare the structure of the atria and ventricles - how are they different?  Why is that?

Atria: thin muscular walls, blood enters them through a blood vessel and leaves through a valve

Ventricles: thick muscular walls, blood enters them through a valve and leaves through a blood vessel

Atria are smaller than ventricles, and have less cardiac muscle. While the ventricles are used to pump blood to other regions of the body, the atria's only purpose are to pump blood into the ventricles themselves, and fill them up with blood. Also, the atria have valves in them them to prevent blood from coming back into them from the ventricles.

Did you notice a difference between the veins and arteries entering and leaving the heart?  How is their structure different?

Veins: thin muscular wall and little elastic tissue 

Arteries: thick muscular wall and have lots of elastic tissue

1) Arteries carry blood away from the heart while veins carry blood to the heart.

2) Arteries have thick and muscular walls (as they have to endure higher pressure) whereas veins have thin and slightly muscular walls.

3) Arteries have no valves, while veins have valves.

4) Arteries (in the post-fetal human) carry oxygenated blood except for the pulmonary arteries. Veins (in the post-fetal human) carry de-oxygenated blood except for the pulmonary veins.

Describe the valves that you found in the heart - what are their functions?

AV Valves (Tricuspid & Mitral)

-Tricuspid is located between the right atrium and right ventricle, closes when the right ventricle contracts therefore the blood from the ventricles are able to go out of the heart  

-Mitral is located between the left atrium & left ventricle, closes when left ventricle contracts, preventing back flow of blood into left atrium

Semi-lunar Valve:

Allows blood to flow from atria to ventricles, & prevent back flow of blood when the ventricles contract

What surprised you about dissecting the heart?  Why?

Unfortunately I was too sick to my stomach to actually participate in the dissection of the heart and decided to be a disturbed bystander. However, as I watched the dissection take place I was could not help but stare in awe and shock. It was hard to believe that such a little thing was so complicated and played such a great role in the functioning of our bodies. What surprised me the most was that I was actually able to recognize parts of the heart that we had learnt about in class. This dissection was a great experience and made me realize how complicated the structure of a heart actually is.