Science · Grades 4–7
The Circulatory System
Science lesson covering the heart, blood vessels, and how blood carries oxygen and nutrients throughout the body.
Subject
Science
Grade Level
Grades 4–7
Resource Type
Worksheet
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Free lesson · PDF: Full Member
Reading Passage
The Circulatory System
The circulatory system is the body’s transportation network, moving blood throughout every organ and tissue. At the center of this system is the heart, a hollow muscle about the size of a fist that beats around 100,000 times per day. The heart acts as two pumps working side by side — one side sends oxygen-poor blood to the lungs, and the other side sends oxygen-rich blood to the rest of the body.
Blood travels through the body via a network of vessels. Arteries carry blood away from the heart under high pressure, while veins return blood to the heart. Capillaries are the smallest vessels, where oxygen and nutrients pass into body tissues and carbon dioxide and waste products pass back into the blood.
The heartbeat sound you hear through a stethoscope is made by the valves inside the heart snapping shut. These valves prevent blood from flowing backward, keeping circulation moving in one direction. You can feel your pulse at points where arteries run close to the skin — at the wrist, neck, and temples.
Keeping the circulatory system healthy involves regular exercise, a balanced diet, and avoiding smoking. Exercise strengthens the heart muscle and improves circulation. High blood pressure, caused by blocked or stiff arteries, is one of the most common and preventable risks to circulatory health.
Printable Worksheet
Printable PDF · 3 pages
Circulatory System Worksheet
Science lesson on the circulatory system with comprehension questions and answer key. Covers the heart, blood vessels, pulse, and blood circulation. Printable PDF.