What Does Skin Do? Skin, our largest organ, has many jobs. It: protects the network of muscles, bones, nerves, blood vessels, and everything else inside our bodies forms a barrier that prevents harmful substances and germs from entering the body protects body tissues against injury helps control body temperature through sweating when we’re hot and by helping keep …
Why Are the Mouth and Teeth Important? Every time we smile, frown, talk, or eat, we use our mouths and teeth. Our mouths and teeth let us make different facial expressions, form words, eat, drink, and begin the process of digestion. The mouth is essential for speech. With the lips and tongue, teeth help form …
What Is Metabolism? Metabolism (pronounced: meh-TAB-uh-liz-um) is the chemical reactions in the body’s cells that change food into energy. Our bodies need this energy to do everything from moving to thinking to growing. Specific proteins in the body control the chemical reactions of metabolism. Thousands of metabolic reactions happen at the same time — all …
What Is Reproduction? Reproduction is the process by which organisms make more organisms like themselves. But even though the reproductive system is essential to keeping a species alive, unlike other body systems, it’s not essential to keeping an individual alive. In the human reproductive process, two kinds of sex cells, or gametes (pronounced: GAH-meetz), are involved. The …
What Are the Lungs and Respiratory System? The lungs and respiratory system allow us to breathe. They bring oxygen into our bodies (called inspiration, or inhalation) and send carbon dioxide out (called expiration, or exhalation). This exchange of oxygen and carbon dioxide is called respiration. What Are the Parts of the Respiratory System? The respiratory …
What Are the Kidneys and Urinary Tract? The urinary tract is one of the systems that our bodies use to get rid of waste products. The kidneys are the part of the urinary tract that makes urine (pee). Urine has salts, toxins, and water that need to be filtered out of the blood. After the kidneys …
Whether you’re stomping through the showers in your bare feet after gym class or touching the bathroom doorknob, you’re being exposed to germs. Fortunately for most of us, the immune system is constantly on call to do battle with bugs that could put us out of commission. What Is the Immune System? The immune system is …
What Does the Heart Do? The heart is a pump, usually beating about 60 to 100 times per minute. With each heartbeat, the heart sends blood throughout our bodies, carrying oxygen to every cell. After delivering the oxygen, the blood returns to the heart. The heart then sends the blood to the lungs to pick up more oxygen. This …
What Is Reproduction? Reproduction is the process by which organisms make more organisms like themselves. But even though the reproductive system is essential to keeping a species alive, unlike other body systems, it’s not essential to keeping an individual alive. In the human reproductive process, two kinds of sex cells, or gametes (GAH-meetz), are involved. The male …
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