February 12th, 2016 Hiroshima by John Hersey

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Directions: ANSWER USING COMPLETE SENTENCES! Use the information you have been given to answer questions about: The Circulatory System.

Subject: The Circulatory System: The Heart

Level#1: The heart is the main organ of the circulatory system. It is about the size of a closed fist. The heart is made of cardiac muscle. The heart works by pumping and relaxing. These actions keep blood flowing throughout the body.

1. What is the main part of the circulatory system?






2. How big is the heart?





3. What is the heart made of?







Level#2: The heart is the main organ of the circulatory system. It is about the size of a closed fist. The heart is made of cardiac muscle. The heart works by pumping and relaxing. These actions keep blood flowing throughout the body. The heart is divided into four parts or chambers. The two top chambers are called atria (singular atrium). The bottom two chambers are called ventricles. Valve open and close to control the direction of blood flow.

1. What is the main organ of the circulatory system?





2. What size is the heart and what is it made of?





3. How does the heart work and what do the actions of the heart do?






Level#3: The heart is the main organ of the circulatory system. It is about the size of a closed fist. The heart is made of cardiac muscle. The heart works by pumping and relaxing. These actions keep blood flowing throughout the body. The heart is divided into four parts or chambers. The two top chambers are called atria (singular atrium). The bottom two chambers are called ventricles. Valve open and close to control the direction of blood flow. First, blood flows into the right atrium. From there, it is pumped in the right ventricle. Then, arteries carry the blood to the lungs. In the lungs, the blood picks up oxygen. Now, the oxygen-rich blood returns to the left atrium through large veins. The heart pumps the blood into the left ventricle. From there, it moves through the aorta and out to the body. The blood delivers nutrients and oxygen to all cells.

1. What is the main organ of the circulatory system, how big is it, and what is it made of?







2. How does the heart work and what do the actions of the heart accomplish?








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