 A sheep heart is nearly identical to a  human heart in size and structure. It possesses the same four chambers you’re  likely already familiar with, which continuously fill and pump out blood to ensure  that oxygen is always circulating in a sheep’s bloodstream.
            A sheep heart is nearly identical to a  human heart in size and structure. It possesses the same four chambers you’re  likely already familiar with, which continuously fill and pump out blood to ensure  that oxygen is always circulating in a sheep’s bloodstream.
            
            As you dissect a sheep heart, however, you  can locate a few differences in their structure. Recall that deoxygenated blood  enters the heart through two great vessels, namely the superior (top) and  inferior (bottom) vena cava. For sheep, instead of an inferior great vessel,  they have a posterior vena cava connected to the back of the heart.
            
            Sheep share the mammalian heart plan, with  two atria and two ventricles. The chambers on the right side work to oxygenate  blood, while those on the left side pump the blood back into the bloodstream.  As many people enjoy sheep for meals, sheep hearts can be great models to learn  about your own heart’s anatomy, being fairly accurate and readily-available.