Sheep Heart Dissection Essays

898 Words Dec 28th, 2012 4 Pages
Sheep Heart Dissection
Purpose: Sheep have a four-chambered heart, just like humans. By studying the anatomy of a sheep's heart, you can learn about how your own heart pumps blood through your body and keeps you alive!.
Observation: External Anatomy
Most heart diagrams show the left atrium and ventricle on the right side of the diagram. Imagine the heart in the body of a person facing you. The left side of their heart is on their left, but since you are facing them, it is on your right.

1. Identify the right and left sides of the heart. Look closely and on one side you will see a diagonal line of blood vessels that divide the heart. The half that includes all of the apex (pointed end) of the heart is the left
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The aorta branches into more than one artery right after it leaves the heart, so it may have more than one opening on your heart specimen. Look carefully at the openings and you should be able to see that they are connected to each other.
4. Behind and to the left of the aorta there is another large vessel. This is the pulmonary artery which takes blood from the right ventricle to the lungs.
Dissection: Internal Anatomy

1. Insert your dissecting scissors or scalpel into the superior vena cava and make an incision down through the wall of the right atrium and ventricle, as shown by the dotted line in the external heart picture. Pull the two sides apart and look for three flaps of membrane. These membranes form the tricuspid valve between the right atrium and the right ventricle. The membranes are connected to flaps of muscle called the papillary muscles by tendons called the chordae tendinae or "heartstrings." This valve allows blood to enter the ventricle from the atrium, but prevents backflow from the ventricle into the atrium.
2. Insert your probe into the pulmonary artery and see it come through to the right ventricle. Make an incision down through this artery and look inside it for three small membranous pockets. These form the pulmonary semilunar valve which prevents blood from flowing back into the right ventricle.

3. Insert your dissecting scissors or scalpel into the left auricle at

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