Source of the universally recognised sound of nervousness, the human heart is on full display here. This anatomical model reveals the different layers of the heart as found in mammals and birds, the size suggesting human. Uncover section by section how fascinatingly intricate this crucial organ is textured and organised. However, should this two-dimensional model not satisfy your curiosity, a sheep’s heart is about the same size as that of a human’s and significantly easier to come by.