The Heart and Circulation

Syllabus tag: KCSE | Biology | Form 2 | Topic 2 Transport in Animals

Lesson objectives

By the end of this topic, you should be able to:

• Describe the structure of the mammalian heart.
• Explain the cardiac cycle and the role of the valves.
• Trace the double circulation through named vessels.
• Explain tissue fluid, lymph and diseases of the circulatory system.

Summary

The mammalian heart is a four-chambered muscular pump. The right side handles deoxygenated blood to the lungs and the left side oxygenated blood to the body, and the two never mix. The left ventricle wall is thickest because it pumps furthest. Valves ensure blood flows one way only, and their closure produces the heart sounds.