Muscles Lesson 1 Think about how we move every day. Each morning we eat breakfast, brush our teeth, and tie our shoes. Later, we write in class, kick a ball outside, or lift a heavy bag. All of these movements rely on our muscles. Muscle is a soft tissue found in humans and animals. Muscles produce force and motion. Muscles have a lot of jobs. They keep our bodies upright. They power all of our actions. Muscles also keep our internal organs working. For example, muscles keep the heart pumping to circulate our blood. 1. What are the three functions of the muscular system? Give an example 1. 2. 3. Example Muscles work when electrical signals travel from your brain along nerves and to the muscle. The signal tells a muscle to contract. Most muscles are connected to bones. They are attached by tendons. As they contract, muscles get shorter, pulling on the bone. This forces the bones to move. Muscles usually work in pairs. While some muscles contract, others get longer. 1. How do muscles work? 2. How are muscles connected to bones? What happens when muscles contract? Think about bending your arm. Your biceps contracts and pulls while your triceps relaxes to allow your arm to move. Now, to straighten your arm back out again, your biceps relaxes and your triceps contracts. This is how your muscles work together to support and allow you to move so skillfully. 1. Explain how triceps and biceps work together to allow your arm to move 2. How do you think you can make your muscles stronger?
