#5 Cardiovascular II Blood Vessels

Transcription

1 Page1 #5 Cardiovascular II Blood Vessels Objectives: Observe slide of artery and vein cross-section Identify a list of human arteries and veins using a virtual human dissection Dissect and identify a list of arteries and veins in the cat Equipment: Remember to bring gloves, goggles, dissecting kit, appropriate shoes, and photographic atlas. I. Introduction Blood vessels Blood vessels are the functional units of the cardiovascular system. Every cell in the body depends on a close association with the vascular system to sustain homeostasis. In general, systemic arteries deliver blood, rich with oxygen and nutrients, to capillary networks interspersed within the organs and tissues. The systemic veins drain the capillary networks and return the blood, high in carbon dioxide and wastes, to the right side of the heart. The pulmonary arteries deliver deoxygenated blood to the lungs. After carbon dioxide is exchanged for oxygen, the pulmonary veins return oxygenated blood to the left side of the heart. Figure 1a. Human systemic arterial circulation (Saladin). Last updated 06/18/2012

2 Page2 Figure 1b. Human venous circulation (Saladin). II. Observation of Artery and Vein Slide Obtain the artery and vein cross-section slide (HA 21). Locate the artery (thick-walled, more obvious vessel) and the vein (thin-walled, collapsed). Identify the following structures: Artery: tunica interna endothelium tunica media smooth muscle tunica externa connective tissue Vein: tunica interna endothelium tunica media smooth muscle tunica externa connective tissue Figure 2. Artery and vein (from AP Revealed).

3 Page3 III. Virtual Human Blood Vessel Examination Preparation 1. Start the Anatomy & Physiology Revealed software by double clicking its icon. 2. On the home screen select Cardiovascular from the Module (top center) drop down menu. 3. Click the dissection icon (next to Module). 4. In the Structure List column (top left) choose thorax from the Topic drop down menu. 5. Choose Arteries-anterior from the View drop down menu. 6. Use the layer tools and the instructions below to navigate between layers. Locate the various structures by activating the labeling pins when appropriate. B. Virtual Artery Examination: Cardiovascular system, thorax, arteries-anterior, dissection layer 4 Arteries APRevealed 1. aorta 1a. aortic arch 1b. thoracic aorta 2. brachiocephalic artery 3a. right common carotid artery 3b. left common carotid artery 4a. right subclavian artery 4b. left subclavian artery 1. Move to Layer 4 (APR Fig. 1) and locate the structures on the left. 2. Move to Layer 6 to locate the right common carotid a. (3a) and the thoracic aorta (1b). 3. The brachiocephalic a. (2) divides into the right common carotid a. (not shown here) which supplies the head and the right subclavian a. (4a) which supplies the arm. 4. Another useful AP Revealed resource is the computed tomography angiography (CTA) bank of images. While Cardiovascular is still selected in the Module box, click on the imaging icon. From the Topic drop down menu choose Aortic arch-cta-oblique view (APR Fig. 2). Trace the path of the aorta as it descends posterior to the heart. 4a 2 1a 1 APR Fig. 1 1b APR Fig. 2 3b 4b

4 Page4 Cardiovascular system, shoulder and arm, vasculature-anterior dissection layer 8 Arteries 4b. left subclavian artery 5. axillary artery (left and right) left shown in these views 6. brachial artery (left and right) left shown in these views 1. Click on the dissection icon and choose Shoulder and arm from the Topic drop down menu. Choose Vasculatureanterior from the View menu. Move to Layer 8 (APR Fig. 3). 2. Although the left subclavian a. (APR Fig. 1) branches directly from the aorta and the right subclavian a. does not, both arteries become the axillary a. (5) at the level of the first rib, as the artery enters the upper arm. At the point where the deltoid and biceps meet, the axillary a. becomes the brachial a. (6). 3. Go to Topic: Shoulder, View: Vascular arteries, Layer 5 to see the exact boundaries of each artery (APR Fig. 4). APR Fig. 3 APR Fig. 4 Cardiovascular system, shoulder and arm, arteries-anterior, layer 2 Arteries 4b. left subclavian artery 5. left axillary artery 6. left brachial artery 1. For some views, there are orientation diagrams available. To see the diagram for the arteries that supply the upper limbs, go to Topic: Shoulder and arm, View: Arteriesanterior, Layer 2 (APR Fig. 5). 2. Click on each vessel in the list on the left to see the boundaries. 4b 5 6 APR Fig. 5

5 Page5 Cardiovascular system, head and neck, vasculature-lateral dissection layer 4 Arteries 3a. right common carotid artery 7. internal carotid arteries 8. external carotid arteries 1. Go to Topic: Head and neck, View: Vasculature-lateral, Layer 4 (APR Fig. 6). 2. The internal carotid a. (7) has a slightly larger diameter than the external carotid a. (8). The internal carotid a. is posterior to the external carotid a. 7 3a 8 APR Fig. 6 Cardiovascular system, abdomen, celiac trunk-anterior, dissection layer 6 Arteries 1b. abdominal aorta 9. celiac trunk 10. superior mesenteric artery 11. renal arteries (right and left) 12. common iliac arteries 13. external iliac arteries 14. internal iliac arteries 1. Go to Topic: Abdomen, View: Celiac trunk-anterior, Layer 6 (APR Fig. 7). 2. The aorta descends from the thorax to the abdomen through the diaphragm (D). The first artery that branches from the abdominal aorta is the celiac trunk (9). 3. Just inferior to the celiac trunk is the superior mesenteric a. (10) which supplies blood to many of the GI organs. 4. The renal arteries (11) supply the kidneys. 5. The aorta branches into the right and left common iliac a. (12) in the pelvic region. 6. Use CTA to visualize the point at which the common iliac a.(12) split into the external(13) and internal (14) iliac a. Click on the imaging icon and choose Abdominal aorta and iliac arteries. The correct image will appear (APR Fig. 8) b APR Fig D 10 APR Fig

6 Page6 Cardiovascular system, hip and thigh, vasculature-anterior, dissection layer 4 Arteries 15. femoral arteries 1. Click on the dissection icon and go to Topic: Hip and thigh, View: Vasculature-anterior, Layer 4 (APR Fig. 9). 2. As the external iliac a. enters the thigh, it becomes the femoral a. (15). 3. To bring up an orientation diagram of the veins that drain the lower limbs, click on the pin marking the femoral a. 15 APR Fig. 9 Cardiovascular system, thorax, veins-anterior, dissection layer 4 Veins 16. vena cava a. superior b. inferior (not visible in this view) 17. brachiocephalic veins 18. subclavian veins 19. internal jugular veins 20. external jugular veins 1. Go to Topic: Thorax, View: Veins-anterior, Layer 4 (APR Fig. 10). 2. The superior vena (16a) empties into the right atrium. The right and left brachiocephalic v. (17) empty into the superior vena cava. They are formed from the union of the subclavian v. (18), which drain the upper limbs, and the internal jugular v. (19), which drain the head along with the external jugular v. (APR Fig. 10). 3. For a lateral view of the right internal and external jugular v., go to Topic: Head and neck, View: Vasculature-lateral (APR Fig. 10). The external jugular v. can be seen in Layer 2 (APR Fig. 11) and the internal jugular v. can be seen in Layer a APR Fig APR Fig. 11

7 Page7 Cardiovascular system, shoulder and arm, vasculature-anterior dissection layer 6 Veins 1. Go to Topic: Shoulder and 18. subclavian veins arm, View: Vasculatureanterior, Layer 6 (APR Fig. 12). 21. axillary veins 22. brachial veins APR Fig. 12 shows the left side 2. The axillary v. (21) drain the upper limbs and become the subclavian v. as the vessel enters the thoracic cavity. 3. The brachial v. (22) drain the antebrachia and empty directly into the axillary v. 4. For a diagram of this region, go to Topic: Shoulder and arm, View: Veins-anterior, Layer APR Fig Cardiovascular system, abdomen, Veins-anterior, dissection layer 6 Veins 16b. inferior vena cava 23. renal veins 24. common iliac veins 1. Go to Topic: Abdomen, View: Veins-anterior, Layer 6 (APR Fig. 13). 2. The renal v. (23) drain the kidneys (K) and empty directly into the inferior vena cava (16b) which carries blood from the lower body into the right atrium. In the pelvic region the right and left common iliac v. (24) join to form the inferior vena cava. K 16b K 24 APR Fig. 13

8 Page8 Cardiovascular system, abdomen, Veins-anterior, dissection layer 6 Veins 24. common iliac veins 25. internal iliac veins 26. external iliac veins 27. femoral veins (right and left) 1. Go to Topic: Pelvis-male: Vasculature-anterior, Layer 5 (APR Fig. 14). 2. The internal (25) and external (26) iliac v. join to form the common (24) iliac v. The internal iliac v. drain blood from the pelvic region and the external iliac v. drain blood from the femoral v. (27, APR Fig. 14). 3. Also shown in APR Fig. 13 are the common (12), internal (13), and external (14) iliac a. 4. Go to Topic: Hip and leg, View: Veins-anterior, Layer 4 for an orientation diagram of the veins that drain the lower body (APR Fig. 15) b APR Fig APR Fig. 15

9 Page9 IV. Cat Vessel Dissection 1. Wear goggles, gloves, and an apron for the entire time that you are working with preserved specimens. 2. Use scissors to cut open the bag and remove the cat, but do not let the preservative spill out of the bag. 3. Carefully dump the preservative into a special bin provided at certain lab sinks. DO NOT DUMP THE PRESERVATIVE DOWN THE SINK. 4. The plastic bag should then be thrown away in the regular trash containers. 5. Do not use a scalpel for dissecting out the vessels. 6. For most of your work, use only your blunt probe. It is the safest and most efficient dissecting tool for vessel identification. 7. Use your scissors to open the thoracic and abdominal cavities. The arteries of the cat have been injected with red latex but they appear pink due to the thick arterial walls. The veins have been injected with blue latex and are typically more prominent than the accompanying arteries. The thoracic veins are anterior to the arteries. Take care not to destroy the veins when following the arteries through the tissues. Use Figure 3 to help you locate structures as you perform the dissection. Instructions to remove the cat chest wall: 1. Carefully use scissors to cut through the abdominal wall near the genital opening. It is very thin so take care not to cut into the abdominal viscera. Cut towards the head in a curve up each side until you reach the diaphragm and the rib cage. 2. Cut the diaphragm horizontally so that it separates from the chest wall. 3. Cut through the ribs one at a time using the bone cutters, if necessary, from the diaphragm towards the head, one side at a time. 4. Be careful not to damage the axillary vein and artery as you cut the muscle in the axilla. 5. You may cut the superficial vessels going to/from the anterior part of the chest wall. 6. Carefully remove the chest wall after making sure the tissue near the head/neck is separated. A. Structures and Arteries of the Upper Body Pericardium Heart 1. Aorta 1a. Aortic arch 2. Brachiocephalic artery 3a. Right common carotid artery 3b. Left common carotid artery 4a. Right subclavian artery 4b. Left subclavian artery 5. Axillary arteries (right & left) 6. Brachial arteries (right & left) 7. Internal carotid arteries (right & left) 8. External carotid arteries (right & left)

10 Page10 right common carotid TRACHEA VESSELS OF THE CAT left common carotid right subclavian internal jugular TRACHEA external jugular right subclavian brachiocephalic left subclavian brachiocephalic superior vena cava left subclavian HEART thoracic aorta HEART celiac trunk DIAPHRAGM DIAPHRAGM abdominal aorta superior mesenteric inferior vena cava renal KIDNEY renal KIDNEY external iliac internal iliac internal iliac common iliac external iliac caudal femoral femoral ARTERIES VEINS Figure 3. Diagram of Cat vessels.

11 Page11 Heart The heart is in the center of the thoracic cavity, between the two lungs. Pericardium This thin sac encloses the heart. Snip the pericardium with scissors and peel it back to reveal the surface of the heart. Aorta On the superior aspect, at about the midline, the aorta emerges from the left ventricle, then curves sharply inferior becoming the aortic arch. The superior vena cava might be partially obscuring the aorta. Brachiocephalic artery In the cat, there are only two major branches from the aortic arch; the brachiocephalic artery arises first. This artery moves vertically toward the neck. Right and left common carotid arteries The common carotid arteries branch from the brachiocephalic artery at the same point and then travel vertically on either side of the trachea. Right subclavian artery The right subclavian artery branches from the brachiocephalic and moves toward the right shoulder. Left subclavian artery The second artery to branch from the aortic arch in cats is the left subclavian artery. Insert your blunt probe between the superior vena cava and the brachiocephalic artery. Gently lift the arteries to view the left subclavian artery. With the blunt probe and tweezers, clear away the tissue covering both arteries as they move toward the neck. The left subclavian artery will extend vertically and then move toward the left shoulder. Right and left axillary arteries The subclavian arteries become the axillary arteries as they move out of the thoracic cavity into the armpit area (axilla). Right and left brachial arteries The axillary arteries become the brachial arteries as they enter the upper limb. Internal and external carotid arteries At the top of the trachea, each common carotid artery splits into the external and internal carotid arteries. B. Arteries of the Lower Body 1b. Descending aorta 10. External iliac arteries 11. Internal iliac arteries 12. Femoral arteries 13. Celiac artery 14. Superior mesenteric artery 15. Renal arteries Descending aorta The aortic arch curves inferiorly as it passes behind the heart. Roll the left lung aside and lift the heart to follow the descending aorta (thoracic aorta) as it passes through the diaphragm along with the esophagus and the inferior vena cava. Once past the diaphragm, the aorta is referred to as the abdominal aorta.

12 Page12 Right and left external iliac arteries In the pelvic region, the aorta splits into the right and left external arteries. There are no common iliac arteries in cats. The large external iliac arteries continue into the lower limb. Right and left internal iliac arteries The abdominal aorta continues for a short way past the external iliac arteries and then it divides into the right and left internal iliac arteries and the caudal artery. Right and left femoral arteries The external iliac arteries become the femoral arteries as they enter the lower limb. Celiac artery In order to view the abdominal arteries, the abdominal organs must be moved gently to one side. Take care not to damage the organs. The aorta and the inferior vena cava are on the posterior wall of the abdominal cavity. The first artery to branch from the aorta within the abdomen is the celiac artery (trunk). This very short vessel branches anteriorly and immediately divides into three branches. Superior mesenteric artery The second branch of the abdominal aorta is the superior mesenteric artery. It is also anterior and just inferior to the celiac trunk. It branches extensively to supply the intestinal mesentery. Right and left renal arteries Deeper into the abdomen, the renal arteries branch laterally from the aorta and supply the kidneys. C. Veins of the Upper Body 16a. Superior vena cava 16b. Inferior vena cava 17. Brachiocephalic veins 18. Subclavian veins 19. Internal jugular veins 20. External jugular veins 21. Axillary veins 22. Brachial veins Superior vena cava This large vessel enters the right atrium on the superior aspect of the heart. Right and left brachiocephalic veins These two prominent vessels join to form the superior vena cava. Right and left subclavian veins The subclavian veins drain blood from the upper limb and shoulder. They join the external jugular vein to form the right and left brachiocephalic veins. Right and left external jugular veins These large veins travel down the lateral aspect of the neck until they join the subclavian veins to form the brachiocephalic veins. The external jugular veins are larger than the internal jugular in cats. The opposite is true in humans.

13 Page13 Right and left internal jugular veins The internal jugular veins drain the brain and empty into the external jugular veins at the junction with the brachiocephalic veins. Right and left axillary veins These vessels drain blood from the upper limb. They become the subclavian veins as the vessels enter the thoracic cavity. Right and left brachial veins The brachial veins drain the antebrachial regions and empty into the axillary veins. D. Veins of the Lower Body 16b. Inferior vena cava 23. Renal veins 24. Common iliac veins 25. Internal iliac veins 26. External iliac veins 27. Femoral veins Inferior vena cava The inferior vena cava drains blood from the lower body to the right atrium. The vena cava accompanies the descending aorta through the thoracic cavity into the abdomen. Renal veins The large renal veins return blood from the kidneys to the inferior vena cava. Right and left common iliac veins The inferior vena cava is formed from the union of the right and left common iliac veins within the pelvic region. Right and left internal iliac veins The common iliac veins are formed by the union of the internal and external iliac veins. Right and left external iliac veins These vessels drain the femoral veins of the lower limbs. Right and left femoral veins The femoral veins become the external iliac veins as the vessels enter the body from the lower limbs.

14 Page14 E. Directions for Putting Your Cat Away and Cleaning Up 1. All cat parts (fur, fat, connective tissue) should be thrown away in the red biohazard containers. Please do NOT allow cat parts to end up in the sink. They will clog the drain and cause extra work for lab assistants. 2. Spray the entire cat with Preserved Specimen Conditioning Spray. Be careful not to spray yourself, or anyone else, in the face with the spray. 3. Obtain two of the special anti-microbial paper towels. Put on the preservative so that the towels are wet but NOT dripping. Wrap these paper towels tightly around your cat, covering as much of the cat s body as possible. 4. Obtain a NEW plastic bag and place your cat (wrapped in the towels) inside the bag. Pat down the bag to get as much air out of the bag as possible, and then use a large rubber band to seal the bag tightly so that no fluid will leak out. 5. Place the cat into the bins provided as directed by your instructor. 6. Thoroughly wash your dissecting tray with soap and water, dry, and return it to the lab bench where you found it. 7. 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. 8. Dispose of your gloves, paper towels and old plastic bags in the regular trash containers, NOT the red biohazard containers. 9. Make sure that you take your dissecting kit and goggles with you when you leave the lab. References: Kenneth Saladin, Anatomy & Physiology: The Unity of Form and Function, 6 th Edition, McGraw-Hill Publishers, 2011.

15 Page15 Laboratory Report Name: For each label on the diagrams below, give the name of the arteries or the vein on the correct line to the right. A B E F G A. B. C D J H I C. D. E. F. K G. H. I. J. K.

16 Page16 M N L Q R L. M. O S T N. O. P. P Q. R. S. T.