Question

Sheep Heart Dissection Dissecting the sheep heart is an excellent way to learn the anatomy of the heart Not only is the sheep heart similar in size and structure to the human heart the e n d of dissecting the heart enables you to see anatomical details that an artist cannot capture in a drawing or a plastic model Exercise 1: Sheep Heart Dissection You will dissect a preserved sheep heart in this exercise as a comparison study to the anatomy of the human heart. Safety bint: Always wear disposable glowes sehen dissecting to protect your hands from imitating chemicals in the preservative. Also, use the sharp instruments with care and dispose all waste properly as directed by your instructor 1. Obtain a preserved sheep heart, a dissecting tray, dissection instruments, and disposable gloves. Rinse the heart in water to remove excess preservatives. 2. If the pericardial sac is still attached to your specimen, cut it open with a pair of scissors until you can see the heart. Observe the thickness of the parietal pericardium, and note the space between it and the heart surface. What is this space called? _ Now cut the pericardial sac from its attachments and remove it. 3. Observe the surface of the heart. Note the outermost layer of the heart wall, the epicardium (visceral pericardium). Using a scalpel, carefully cut a small piece of the epicardium away from the underlying myocardium. Compare its thickness to that of the parietal pericardium. Now examine the external surface of the heart. Notice the fat distribution, which usually marks the separation of the internal chambers and obscures coronary arteries. With a scalpel. carefully scrape away some of the fat to expose a coronary vessel. 4. Using Figures 3.13a and 3.13b as references, identify the following external features of the heart on both sides of your specimen. When examining the great vessels, use a blunt probe and insert it into the vessel opening, Watch where the probe tip emerges in the heart, which will give you an important clue about the identity of the vessel. right auricle left auricle cpicardium anterior interventricular sulcus aorta parietal pericardium (if present) pulmonary trunk superior vena cava coronary sulcus inferior vena cava base of the heart apex of the heart 5. Obtain a knife with a blade that is 5 inches in length or longer from your lab instructor With the heart on the dissecting tray and its anterior side facing you make a coronal cut through the heart by cutting from the apex toward the base. Use Figures 3.13c and 3.13d as references. Cut through the auricles of both sides, but do not cut all the way through the base and great vessels to avoid separating the two halves. You will now be able to observe both atria and ventricles, as well as the other internal features of the heart.

Answer 1

2. The space between Parital pericardium and heart surface is known as the pericardial cavity. In the pericardial cavity small amount of fluid is present (15-50 cc) which is known as pericardial fluid.