IntroductionReference materialPreparationDissection StepsEntire preparationHeartLungsDissection WorksheetLab reportNotes for Lab #1: Dissection2012: Rob, Brian, Brett, and the legacy of great TA’sJanuary 29, 20141 IntroductionThis Lab allows you to identify and compare the size, shape and tissue type of the major anatomiclandmarks of the heart and lungs. The goal of the lab is not, however, just to observe anatomybut to associate structure with function. The heart is a pump for blood that comes into the rightatrium, goes out through the right ventricle, returns through the left atrium, and leaves againthrough the left ventrical. Imagine the basic knowledge you now have is all the information youpossess and imagine you are the first person to be permitted to dissect this particular type of heart.Try and figure out what the various components are, how each works, especially how the shape,composition, and even texture of each part contributes to its function.2 Reference material• www.biologycorner.com/anatomy/circulatory/heart/heart dissection.html The biologycorner.comdissection of a sheep heart.• www.hometrainingtools.com from the Home Science Tools web site.• www.gwc.maricopa.edu/class/bio202/heart/anthrt.htm from the Biological Sciences Home-Page• Both the lung photos: faculty.washington.edu/kepeter/119/images/lung sections.htm andthe heart photos: faculty.washington.edu/kepeter/119/images/heart sections.htm are fromKaren Petersen at the University of Washington.• Even a YouTube video that walks through the heart structure.Figure 1 shows a diagram for the cow heart geometry that will be useful during the dissection.3 Preparation1. Obtain dissection kit, rubber/latex gloves, and (optionally) fashion yourself a dissection apronfrom the plastic on hand.2. Make sure each group has access to a camera to capture the steps of the dissection.3. Please use care with the instruments–that are sharp!1Figure 1: Diagram of cow heart anatomy.4. Use gloves to keep hands clean—animal blood and tissues are not generally harmful but canbe slightly irritating to the skin.4 Dissection Steps4.1 Entire preparation1. If necessary, wash your preparation clear of excess blood and spread it out on your benchspace.2. Unpack all the dissection tools from the case and lay them out in some organized fashion;put the case and other materials out of harm’s way.3. Lay out the heart and lung preparation on the plastic material and take some time to lookat the large scale anatomy of what you have. Make sure you can tell heart from lungs, leftfrom right. It will get progressively harder to keep track as you take the preparation apartso perhaps even mark the left and right lungs at this stage.4. Carefully separate the heart from the rest of the tissue and dissect it clear, leaving at leasta few centimeters of the major vessels attached. This is harder than it sounds so beespecially careful to keep all chambers of the heart and as much remnant vesslsas possible attached. Typical victims of this process are the pulmonary veins,which enter the posterior wall of the left atrium.24.2 Heart1. Make use of the steps from resources below to help guide the steps for the dissection with onemajor deviation. The best starting approach is often to open the atria, each one separatelyand observe their structure as well as the view of the base of the heart from this superior(top) view. For the right atrium one you have identified and photographed the venae cavae(there should be two) cut along a line between the two openings and gradually extend it.A similar cut across the posterior and/or superior aspects of the left atrium is also a goodstrategy for this chamber. Then before cutting the ventricles, remove the atria so that thebase of the ventricles is completely visible and it is possible to identify (and photography) allthe vessels and valves. This whole process and the separate examination of the completelyremoved atria also facilitates examining the structure of the atria and comparing the left andright side by their structure, color, texture and tactile characteristics.2. Resources:• http://www.hometrainingtools.com• Here are some links to pages of this dissection as PDF files (from Dr. Derek Boughnerat the University of Western Ontario:(a) page 1(b) page 2(c) page 33. Record all measurements in the table in Section 5 below.4. Note: When dissecting the ventricles, make the first cut of the right ventricle described aboveonly to within 5 cm. of the base of the heart, i.e., the part of the heart where ventricles andatria join. Cutting too far will slice through the tricuspid and mitral valves but it is betterto observe and photograph them first intact from both the top and the bottom. Observe thevalves by looking into the incision from the apex of the heart (the tip of the ventricles) towardthe base. Only then, continue the cut to that you can open (or unwrap) the tricuspid andmitral valves.5. Make sure to photograph each step several times so you can include images in the lab reportshowing all the items in the table. Take your time and make lots of photos so you can choosegood ones.4.3 Lungs1. Separate the lungs from the preparation, being careful to preserve access to the bronchi.2. Try and inflate the lungs via the bronchi using the rubber tubing connected to the compressedair lines in the lab.3. Slice open the lungs as in the web site and try to expose bronchi and at least first generationairways (photo).35 Dissection WorksheetFill out as much of the form below as you can. Some boxes are not relevant (e.g., wall thicknessof chordae tendinae) and the choice of size parameters will depend on the structure, but providereasonable estimates for all the values that you can. In the comments section, describe brieflythe notable characteristics of the structure that you observe.Cardiac Structure Dimensions Wall Comments/Diameter(mm) Thickness(mm)Whole HeartSuperior Vena CavaInferior Vena CavaRight AtriumRight VentricleLeft AtriumLeft VentricleMitral ValveAortaLeft Main CoronaryRight Main CoronaryAortic ValveAortic Arch BranchvesselsPulmonary ArteryPulmonic ValvePulmonary VeinsTricuspic ValvePulmonary ArteryBranch VesselsChordae TendinaePulmonary Structure Dimensions Wall Comments/Diameter(mm) Thickness(mm)TracheaLeft Main BronchusRight Main bronchus2nd GenerationBronchus46 Lab reportThe lab report should consist of1. Title and your name, as well as the names of your lab partners.2. A brief (0.5–1 page)