Describes the parts of a rat's circulatory system and how the blood circulates in a rat.

Take a look at the parts of the cardiovascular system including all of the major arteries and veins. Make sure to click on the interactive animation to find additional information.

Describes anatomical features of a spider, including its external structure, eyes, mouth parts, digestive system, circulatory system, respiratory system, nervous system, reproductive system, and its spinnerets.