#4 Cardiovascular I The Heart

Transcription

1 Page1 #4 Cardiovascular I The Heart Objectives: Identify a list of human heart structures using a virtual human dissection Dissect a sheep heart to identify external and internal structures Identify a list of human heart structures on a model Equipment: Remember to bring gloves, goggles, appropriate shoes, photographic atlas. I. Introduction The heart has four chambers two upper atria (singular, atrium) and two lower ventricles. Blood enters the atria from the large veins and passes into the ventricles before being ejected from the heart within the large arteries to either the lungs or the rest of the body (Fig. 1). Figure 1. of the human heart II. Virtual Human Heart Examination Preparation 1. Start the Anatomy & Physiology Revealed software by double clicking the icon. 2. On the home screen, from Module (top center) select Cardiovascular from the drop down Menu. 3. From the icon list at the top center, click the left most icon (the dissection icon). 4. Under the Structure List column (top left) use the Topic drop down menu to choose Thorax. 5. From the View drop down menu choose Arteries-anterior. Do not select a Structure Type at this point. 6. At the bottom of the left column are the layer tools. Move the red arrows down to gradually remove each layer of the body. The layers must be removed in order. Remove Layers 1 and 2 to visualize the pericardium in Layer 3.

2 Page2 7. To identify visible structures within a layer, click on the radio button at the top of the layer that is on display. Pins will appear marking labeled structures. 8. Hover over a pin and the name of the structure will appear. Or click on a pin and the structure will be highlighted in the main view and further information on the structure will appear in the various boxes in the left column. Another identification method is to click on the name of the structure in the information section. 9. Practice using the layer tools and highlighting structures by clicking on the pin or structure name. III. Virtual Human Heart Examination Cardiovascular system, thorax, arteries-anterior, dissection layer 3 1. pericardium (also known as pericardial sac) 1. The introductory instructions on page 2 will bring you to this view (APR Fig. 1). 2. Note the position of the heart within the thoracic cavity. 3. The heart is enclosed in the double-layered pericardium (APR Fig. 1). 1 APR Fig.1 Cardiovascular system, thorax, arteries-anterior, dissection layer 4 2. heart 3. aorta a. aortic arch b. brachiocephalic c. left common carotid d. left subclavian 4. pulmonary trunk 5. vena cava a. superior b. inferior (not shown) 1. Use the layer tool to move one layer deeper (Layer 4). The pericardium is removed in this layer revealing the major vessels associated with the 5a heart (APR Fig. 2). 2. Use the labeling pins to locate 3 4 the aorta (3), superior vena cava (5a), and pulmonary 2 trunk (4). 3. Note: the vessels branching from the aorta are labeled in APR Fig 3. APR Fig. 2

3 Page3 Cardiovascular system, thorax, arteries-anterior, dissection layer 5 3. aorta a. aortic arch b. brachiocephalic c. left common carotid d. left subclavian 1. Use the layer tool to move to Layer 5 (APR Fig. 3). 2. The anterior veins have been removed to reveal the arteries branching from the aortic arch. 3. Locate the aorta arch (3a), brachiocephalic (3b), left common carotid (3c), and left subclavian (3d) a. 3b 3c 3a 3d APR Fig. 3 Cardiovascular system, heart, vasculature-anterior, dissection layer 2 6. coronary arteries 7. pulmonary arteries (not shown in this view) 8. right and left pulmonary veins (right shown in this view) 1. To see the heart details, choose Heart from the Topic drop down menu in the left column. Choose Vasculatureanterior under the View menu. Move to Layer 2 (APR Fig. 4). 2. Use the labeling pins for all three layers to locate the structures on the left. Also shown in this view are the cut end of the superior and inferior vena cavae (5a,b). 8 5a 5b 6a APR Fig. 4 6b Cardiovascular system, heart, internal features-anterior, dissection layer 1 9. auricle 10. ventricle 11. apex 1. Choose Heart from the Topic menu and Internal featuresanterior from the View menu (APR Fig. 5). 2. Use the labeling pins to locate the structures on the left 9a 9b 10a 10b 11 APR Fig.5

4 Page4 Cardiovascular system, heart, internal features-anterior, dissection layer atrium (atria, pl.) 13. interventricular septum 14. atrioventricular valve (tricuspid) (bicuspid) 15. papillary muscle 16. chordae tendineae 17. semilunar valve a. pulmonary (not visible in this figure) b. aortic III. Sheep Heart Dissection 1. Move to Layer 5 (APR Fig. 6). 2. In this view, move up and down through Layers 2-6 to find the appropriate labeling pins for the structures on the left. APR Fig. 6 A. Preparation 1. Wear goggles, gloves, and an apron for the entire time that you are working with preserved specimens. 2. Obtain a dissecting tray and a sheep heart. B. Exterior Observations auricles (right and left) ventricles (right and left) apex pulmonary trunk aorta Use your atlas to orient the heart. The prominent features on the anterior surface are the left auricle and the pulmonary trunk. Most of the vessels will emerge on the posterior surface, however, they might have been cut close to the heart and only the openings will be visible. The apex is composed of the left ventricle. C. Interior Observations 17b 12a 14a 12b 14b atria (right and left) ventricles (right and left) interventricular septum atrioventricular valves tricuspid (right) bicuspid/mitral (left) semilunar valves aortic pulmonary chordae tendineae papillary muscle

5 Page5 Make a frontal section with your scalpel by cutting through the center of the left auricle toward the apex. Continue the cut around the apex and up through the right auricle. Note that the heart is asymmetrical. The left ventricle makes up apex, is the largest chamber of the heart with the thickest wall. The interventricular septum separates the two ventricles. The right ventricle is slightly posterior to the left ventricle and much smaller. Locate the atrioventricular valves between the atria and ventricles. The chordae tendineae are attached to the inferior aspect of the valves. Papillary muscles bind the chordae tendineae to the ventricle walls. The aortic and pulmonary semilunar valves are at the junction of the atria with the aorta and pulmonary trunk, respectively. Confirm the location of each vessel by inserting a blunt probe through the atria. D. Directions for Cleaning Up 1. All specimen tissue should be thrown away in the red biohazard containers. Please do NOT allow tissue to end up in the sink. They will clog the drain and cause extra work for lab assistants. 2. Thoroughly wash your dissecting tray with soap and water, dry, and return it to the lab bench where you found it. 3. Use the spray disinfectant cleaner provided to thoroughly wipe down your lab bench area so that it will be ready for the next group of students. 4. Dispose of your gloves, paper towels and old plastic bags in the regular trash containers, NOT the red biohazard containers. 5. Make sure that you take your dissecting kit and goggles with you when you leave the lab. IV. Heart Model Observation Locate the following structures on the human heart model: aorta brachiocephalic left common carotid left subclavian pulmonary trunk vena cava superior inferior auricle right left ventricle right left apex pulmonary arteries pulmonary veins atria right left interventricular septum atrioventricular valve right (tricuspid) left (bicuspid or mitral) papillary muscle chordae tendineae semilunar valve pulmonary aortic

6 Page6 Cardiovascular I The Heart Name: Laboratory Report For each label in the human heart figure above, give the name of the structure on the correct line below. A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. P.