Notes for Lab #1: Dissection

2007: Rob and Brian

• 1 Introduction
• 2 Reference material
• 3 Preparation
• 4 Dissection Steps
  • 4.1 Heart
  • 4.2 Lungs
  
  
• 5 Dissection Worksheet
• 6 Lab report
• About this document ...

1 Introduction

This Lab allows you to identify and compare the size, shape and tissue type of the major anatomic landmarks of the heart and lungs. The goal of the lab is not, however, just to observe anatomy but to associate structure with function. The heart is a pump for blood that comes into the right atrium, goes out through the right ventricle, returns through the left atrium, and leaves again through the left ventrical. Imagine this is all the information you had and imagine you are the first person to be permitted to dissect one. 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.heartlab.robarts.ca/dissect/dissection.html from the University of Western Ontario Heart Valve Lab
• www.salineschools.com/users/spinac/sciencepics.htm from the Mr. Spina's website at the Saline Schools

• www.gwc.maricopa.edu/class/bio202/heart/anthrt.htm from the Biological Sciences HomePage
• Both lung photos faculty.washington.edu/kepeter/119/images/lung_sections.htm and heart photos faculty.washington.edu/kepeter/119/images/heart_sections.htm from Karen Petersen at the University of Washington.
• http://www.shcc.edu.hk/~is/lung.htm from the Integrated Science Department at the Sacred Heart Canossian College in Hong Kong.

Figure 1: Diagram of cow heart anatomy.

 

Figure 1 shows a diagram for the cow heart geometry that will be useful during the dissection.

3 Preparation

1. Obtain dissection kit, rubber/latex gloves, and (optionally) fashion yourself a dissection apron from 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!
4. Use gloves to keep hands clean--animal blood and tissues are not harmful but can be slightly irritating to the skin.

4 Dissection Steps

1. If necessary, wash your preparation clear of excess blood and spread it out on your bench space.
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 look at the large scale anatomy of what you have. Make sure you can tell heart from lungs, left from right. It will get progressively harder to keep track as you take the preparation apart so 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 least a few centimeters of the major vessels attached. Be especially careful to keep all chambers of the heart attached.

4.1 Heart

1. Follow the steps from www.heartlab.robarts.ca/dissect/dissection.html and record your measurements in the table in Section 5 below.
2. If there is no web access, you can see the pages of this dissection as PDF files (from Dr. Derek Boughner at the University of Western Ontario:
   1. page 1 (http://www.cvrti.utah.edu/~macleod/www/bioen/be6000/labnotes/l1-dissect/heartdissection-page1.pdf)
   2. page 2 (http://www.cvrti.utah.edu/~macleod/www/bioen/be6000/labnotes/l1-dissect/heartdissection-page1.pdf)
   3. page 3 (http://www.cvrti.utah.edu/~macleod/www/bioen/be6000/labnotes/l1-dissect/heartdissection-page1.pdf)
3. Note: Make the first cut of the right ventricle described above only to within 5 cm. of the base of the heart, i.e., the part of the heart where ventricles and atria join. If you cut too far, you will slice through the tricuspid valve. Observe the valves by looking into the incision from the apex of the heart (the tip of the ventricles) toward the base. Only then, continue the cut to that you can open (or unwrap) the tricuspid valve.
4. Make sure to photograph each step so you can include images in the lab report showing all the items in the table. Take your time and make lots of photos so you can choose good ones.

4.2 Lungs

1. 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 compressed air lines in the lab.
3. Slice open the lungs as in the web site and try to expose bronchi and at least first generation airways (photo).

5 Dissection Worksheet

Fill out as much of the form below as you can. Some boxes are not relevant but provide reasonable estimates for all the other values. In the comments section, describe briefly the notable characteristics of the structure that you observe.

Cardiac Structure	Diameter	Wall	Comments
	(mm)	Thickness(mm)
1)Superior Vena Cava
2) Inferior Vena Cava
3) Right Atrium
4) Right Ventricle
5) Pulmonary Artery
6) Pulmonary Veins
7) Left Atrium
8) Left Ventricle
9) Aorta
10) Left Main Coronary
11) Right Main Coronary
12) Aortic Valve
13) Pulmonic Valve
14) Mitral Valve
15) Chordae Tendinae
16) Tricuspic Valve
17) Pulmonary Artery Branch Vessels
18) Aortic Arch Branch vessels

Pulmonary Structure	Diameter	Wall	Comments
	(mm)	Thickness(mm)
1) Trachea
2) Left Main Bronchus
3) Right Main bronchus
4) 2nd Generation Bronchus

6 Lab report

The lab report should consist of

1. A brief Introduction to what you did and what the purpose of the lab was. What was the question and what were the goals of the lab, as you perceived them?
2. A Results section that includes text and photos of the steps of the dissection. In the photos, identify the objects, organs, or structures of interest. All photos should be digital and incorporated into the document, i.e., no cutting and pasting of paper photos. Each photo must be numbered and have a caption. Also include in this section the table of values you recorded from the preparation.
3. A Discussion section in which you select one major anatomical feature of the heart, e.g., one valve, coronary circulation, one chamber, and discuss how its function is related to its structure. Features you might include in this description are the shape, the composition and mechanical properties of the tissue, the texture of any surfaces involved; for each feature, try and suggest functional significance and how the function is linked to the structure. This should be at least a half (single-spaced) page of text and whatever images or supplementary diagrams you think are relevant. Again, try to describe this as though you were the first to ever make the connection and provide evidence from your observations for everything you claim.

Please use sentences and proper grammar in the report. See the homework ground rules and tips on the class web site for additional suggestions.

Reports should be single spaced and include color where it is useful. If you do not have access to a color printer, submit the report electronically in pdf format and I will print it. Electronic submission (to macleod@cvrti.utah.edu) is fine, as long as you use a format that will withstand the rigors of transmission and conversion to another computer. Word documents rarely come through unscathed so try to make PDF documents from them first.

The lab report is due two weeks after the lab, which just happens to be when we have our next lab.

About this document ...

Notes for Lab #1: Dissection

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