Heart and Lung Dissection Name(s) Before you begin any work or dissection of your specimen, please try to identify the following. You will need to illustrate what you see, so make sure to note size, texture (how it feels), color. 1. Sketch the heart and lungs (Plucks). Note the general shape and size, color and texture of the lungs. If possible, measure their size and mass. Can you compare the possible volume to that of the balloon you used in your lung capacity lab. 2. Identify The Trachea or windpipe (the main tube bringing air into and out of the lungs). Cartilaginous hoops in the trachea - these are horseshoe shaped and keep the trachea open for the passage of air, but allow the tube to bend and flex easily. The Oesophagus runs in the groove along the open end of the horseshoe shape which allows lumps of food to pass smoothly down to the stomach. The Bronchi - these are the air tubes leading from the trachea to the right and left lungs. Bronchioles - These are the fine tubes leading from the bronchi Any vessels linking the heart to the lungs. Arteries have thick rubbery walls. The veins have much thinner walls. Make sure you feel inside these vessels. The Pleural Membrane - this is the thin layer of connective tissue covering the lungs. The Pericardium - This is the layer of tissue surrounding the heart 3. Cut a small piece of spongy lung tissue to examine more closely. Drop it into a beaker of water. Does it float? If so, why?
4. During the lab, you need to take pictures, produce video, or illustrate what you are observing. These images will need to be included in your lab write-up and should be properly labeled. Examples would be: the aorta, a vein, atrium, ventricle, what does a valve look like, the lobes of the lung, trachea, oesophagus. 5. Locate the parts of the heart shown in the diagram below: The side shown in this diagram is the ventral side (ie the front - rounded side). Don't cut it yet. Pulmonary artery The two vena cava go into the right atrium - one on the top & one from the bottom The pulmonary veins enter the left atrium from both sides of the heart Coronary artery and vein When you need to see inside the right ventricle, cut here. *see step 7 When you want to open the left ventricle cut here. *see step 9 6. Identify the arteries and veins which come out of the heart. Measure the diameter of the arteries and the thickness of the walls. Describe what the arteries look/feel like? (appearance, colour, texture, etc)
7. Cut open the right side of the heart by attempting to follow the dotted lines on the previous diagram. Begin by Opening the right atrium. To do this, follow these steps: a. Insert a blade of the scissors into the superior vena eava and cut downward through the atrial wall. b. Slowly & carefully open the chamber. Try to locate the tricuspid valve and examine its cusps. What kind of tissue do you think make up these valves? Open the right ventricle as follows: c. Continue cutting downward through the tricuspid valve and the right ventricular wall until you reach the apex of the heart. 8. Describe any differences that may be visible between the right ventricle and right atrium. 9. Open the left side of the heart. To do this, follow these steps: a. Insert the blade of the scissors through the wall of the left atrium and cut downward all the way to the apex of the heart. b. Open the left atrium and locate the four openings of the pulmonary veins. Pass a slender probe through each opening and locate the stump of its vessel. c. Examine the bicuspid valve (mitral valve) and its cusps. What is the purpose of heart valves?
10. Describe how the right ventricle is different from the left ventricle in terms of volume and muscle thickness. Measure the thickness of the muscle walls for each. Are the Atria muscle walls thicker or thinner than the ventricles? Explain why this is the case.
Finally, what can you say about the size (volume) of each of the chambers (atria & ventricles) Are they different sizes? Which is the largest? 13. Locate the aorta, which leads away from the left ventricle. Feel the walls of the aorta. Compare the thickness of the aortic wall with that of other arteries (and veins). What do you notice? What accounts for this difference?
+ * Try to locate smaller veins (venules) and arteries (arterioles) as well as any capillaries? Gently pull on a capillary using a probe. Can you lift up the heart or does the capillary break? Describe some smaller blood vessels below.