Pig Heart Dissection Instructions
Follow these instructions carefully to dissect your heart. Discuss each question with your partner. We will discuss
these questions further in class so please consider them carefully
1. The heart has 4 chambers:
- The right and left atria
- The right and left ventricles
See if you can identify these 4 chambers on your heart. Use the diagrams below to help you
How do you know where the atria end and the ventricles begin? Discuss with your partner what external clues you
have used to figure out where these chambers are.
2. See if you can find the four main blood vessels attached to the heart. There are two arteries and two veins.
Arteries have thicker walls and are found entering at the front (ventral) side of the heart. Veins have thinner walls
and enter the heart at the top of the back (dorsal) side.
3. Why are the right and left sides seemingly on the wrong side?
4. If water was poured into the vena cava, through which vessel would it emerge from the heart?
To inspect the internal structure of the heart, cut through the ventricle walls, along the lines shown in the
diagram. This is best done with a sharp scalpel or a pair of sharp scissors. Be careful at this stage only to cut
through the ventricle walls, leaving the walls of the atria intact. Look carefully inside each ventricle.
5. Which ventricle has thicker walls?
6. Estimate their thickness in mm.
7. Suggest why the walls of the left and right ventricle are of different thicknesses?
Locate and carefully observe the atrioventricular valves between the atrium and ventricle on each side of the
heart.
8. Why is the atrioventricular valve in the right ventricle called the tricuspid valve?
9. Why is the atrioventricular valve in the left ventricle called the bicuspid valve?
10. What is the function of the atrioventricular valves?
Locate the semilunar valves at the entrance to the aorta and pulmonary artery.
11. Why are the valves at the entrance to the aorta and pulmonary artery called semilunar?
Identify the tendons that stretch between the atrioventricular valves and the ventricle walls.
12. What is the function of the tendons that connect the atrioventricular valves?
Cut open the aorta and locate the opening to the coronary artery just above the semilunar valve.
13. Cut open the atria and examine their internal structure. Explain the relative difference in size between the atria
and ventricles.
Locate the opening of the coronary vein in the wall of the right atrium.
14. Examine the openings to the vena cava and pulmonary vein. Do these entry points to the heart contain valves? If
not why?