Special Sub-Topic: The Human Heart
|The body has many cavities which house and protect its organs. The heart is in which cavity?|
the chest. The heart is located almost in the center of the chest cavity. It's closer to the left side.
|What is the average size of your heart?|
The size of your clenched fist.. Usually, a person's heart is the size of their clenched fist. If a person has heart trouble, the heart may be bigger than usual.
|The human heart is divided into sections called chambers. How many chambers does a human heart have?|
4. The heart of all mammals is divided into four chambers. Fish and reptiles have a 2-chambered heart. Tadpoles have a 2-chambered heart, but develop a 3rd chamber when they become adults. No animal has a 5-chambered heart.
|Some of the heart's chambers are located at the top and some at the bottom. What is the name for the top chambers of the heart?|
Atria. The two top chambers are collectively called 'atria'. If we're talking about only one chamber, we call it an 'atrium'. The atria collect blood from all parts of the body and squirt it into the bottom chambers.
|What's the name for the bottom chambers of the heart?|
Ventricles. The bottom chambers are called ventricles. They pump the blood collected from the atria into the lungs and other parts of the body. The human heart's four chambers are the right atrium, left atrium, right ventricle and left ventricle.
|Between the upper and lower chambers of the heart are some leaf-like structures which help blood to flow in one direction. These structures are called valves.
true. The valves between the atria and ventricles act like doors. They open and allow blood from the atria to flow into the ventricles. When the ventricles contract, the valves are closed to prevent blood from flowing back into the atria.
|Which blood vessels return blood to the heart?|
Veins. The tubes which return blood to the heart are called veins. These veins empty blood into the atria. The veins which empty blood into the right atrium, bring blood from all parts of the body except the lungs. The left atrium collects blood from four veins that drain the lungs.
|The number of times the heart beats per minute is called the heart rate. All of the following activities would be likely to increase the heart rate except one. Which one?|
sleeping. When you increase your activities or are afraid, your heart beats faster. This provides more oxygen and food for the cells in the body to do more work. You can tell that the heart is beating faster by feeling your pulse on the inside of the wrist, just below the thumb. You may even feel your heart thumping inside the chest cavity.
|The right side of the heart pumps blood to the lungs. What happens in the lungs?|
The blood loses carbon dioxide and picks up oxygen.. Blood enters the heart through the right atrium, moves to the right ventricle and is pumped to the lungs. Here, carbon dioxide is removed, and oxygen collected. This blood then travels back to the left ventricle of the heart.
|Most of the blood vessels that carry oxygen-rich blood around the body are called arteries. The largest artery in the body is the aorta.|
True. Blood from the left ventricle empties into the aorta which takes it to all parts of the body. The aorta is the largest artery in the body.
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