Morphometric and flow indicator studies of the teleost heart

Abstract

The structure of the heart of four species of Alaskan fishes (Thymallus arcticus, Esox lucius, Lota lota, and Catostomus catostomus) was examined in varying detail. The ventricle constitutes 0.07 to 0.09% of the body weight, 26 to 35% of which consists of an outer, cortical layer, and the balance a spongy, trabeculated inner layer. Blood supply to the cortex comes exclusively from the coronary artery, whereas the inner layer is supplied by venous (deoxygenated) blood from the ventricular lumen. Flow indicator studies implied that the cortical layer receives about half as much blood per unit weight as the inner layer, but probably receives about the same amount of oxygen, since arterial blood contains roughly twice as much oxygen as does venous blood. Calculations of the probable limits for oxygen uptake of the ventricle are made on the basis of data in this study and in the literature.