10 - Cardiovascular

Abstract

The mouse and rat (together referred to as rodent) and human cardiovascular systems have many features in common; however, there are also important differences. As is true in all mammals, both rodents and humans have four-chambered hearts: left and right atria, a dominant left ventricle, and a thinner-walled right ventricle. Although the rodent heart is obviously far smaller than the human heart, the ratio of heart to body weight is similar, as are the relative thicknesses of the right and left ventricular walls. Much of the examination that is done macroscopically on the human heart is, because of the small size, better done microscopically on the rodent heart. In rodents and humans, the majority of heart mass is composed of cardiomyocytes, but significant numbers of other cell types are present, including endothelial cells, fibroblasts, and leukocytes. Differences between the rodent and human hearts include the general shape of the heart; location of the coronary arteries; structure of the valves; thickness of the pericardial sac, epicardium, and endocardium; and prominence of the cardiac skeleton. The anatomy and histological structures of the vasculature in rodents and humans share many features; differences include the thinner walls of rodent arteries and the prominent presence of cardiomyocytes around rodent pulmonary veins. This chapter compares the rodent and human heart, discussing the similarities and highlighting the differences.