Which activity gets your heart pumping more: using the computer, climbing the stairs, jumping rope, running, or walking? Youngsters take a heart rate reading after 30 seconds, one minute, and three minutes of each activity. The handout...

Are spiders related to crabs? Study the order of arthropods with a reading selection about animal diversity. It provides details about each class within the order, as well as vivid pictures and explanatory charts. 

Access Excellence offers detailed information, including diagrams and photos, about the anatomy of the heart and its central role in the circulatory system.

This comprehensive study guide covers the main terms and concepts needed for a unit on the circulatory system.

The circulatory system and how it functions are explained. An interactive diagram shows how blood flows through the heart. Disorders of the heart and the circulatory system are also described.

Describes the anatomy of a fish's circulatory system and how the blood circulates in a fish.

Describes the parts of a pig's circulatory system and how its blood circulates. Circulation in a pig fetus is also described as it has differences.

This thorough resource examinces the several types of circulatory systems and provides drawings of these systems in molluscs, arthropods, and the earthworms.

Overview of the cardiovascular system with labeled diagrams and reviews of the heart, torso, arm, leg, and blood, available through the links on the right.

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

William Harvey, doctor during the Age of Enlightenment, challenged mainstream understanding of the heart and the circulation of blood. Read about his early education and his scientific inquiry.

This site from the Department of Chemistry at the Washington University provides a deetailed study of the role of hemoglobin in blood physiology. The article is somewhat in-depth, complete with pictures, charts, and a bibliography.

A very good site about the circulatory system of a bird. It is reader friendly, and includes a fair amount of information. Good diagram of the circulatory system.

This thorough resource provides listing of ten unique characteristics peculiar to the cardiovascular system along with an examination of these ten factors individually.

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.

A detailed description of the human heart and its parts.

This site from the University of Manitoba provides an explanation of the purpose and structure of the respiratory and circulatory systems. Follow the link to the images.

An extensive page on the circulatory system in general. Scroll down to section 49.3 and you will find a simple comparison of the reptilian system to the other vertebrae systems.

A very good description of the blood and circulatory systems of mammals and the important role that blood plays in the physiology of animals.

An introduction to the different regions of the heart, along with a description of the hearts function. A good overview site.

A concise history of the study of the heart and its anatomy. Includes color pictures and details about the work of Galen, William Harvey, and others.

Causes of heart failure, signs and characteristics of heart failure, pathologic conditions resulting in heart failure, and more are the topics addressed in this thorough resource.

Article on arrhythmias with information about the heart's pacemaker.

A complete reference tool that serves as an illustrated resource for presenting information on heart conditions. Content includes information on what they are, how the heart works, diagnosis, congenital defects, treatment, and long term...