Human body: circulation & health

The heart, blood vessels, blood components, exercise, diet, and drugs

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Try each question. If you're stuck, leave it and come back. The answer key is on the last page.

1
Label the main parts of the circulatory system.
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2
What is the main function of the heart? A) To pump blood around the body B) To clean the blood C) To make new blood cells D) To digest food
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3
True or false? Arteries carry blood away from the heart. A) True B) False
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4
Which component of blood carries oxygen to the body's cells? A) Red blood cells B) White blood cells C) Platelets D) Plasma
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5
True or false? Veins have valves to stop blood flowing backwards. A) True B) False
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6
Put these steps of blood flow in the correct order, starting from when blood picks up oxygen in the lungs. Put these in order: Blood returns to the heart through veins, Heart pumps oxygenated blood into arteries to the body, Oxygen and nutrients pass to cells through capillary walls, Blood picks up oxygen in the lungs
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7
Why does your heart rate increase during exercise? A) Muscles need more oxygen, so blood must flow faster B) The heart gets tired and beats irregularly C) Exercise makes the heart grow larger D) The lungs push the heart to beat faster
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8
Label the chambers of the heart.
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9
The left ventricle has a much thicker muscular wall than the right ventricle. Why? A) It must pump blood all the way around the body at high pressure B) It holds more blood than the right side C) It beats faster than the right side D) It pumps blood to the lungs which are very large
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10
True or false? Eating too much salt can raise blood pressure. A) True B) False
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Answer key

Human body: circulation & health · for parents and teachers

1
z1: Heart; z2: Artery; z3: Vein; z4: Capillaries
The heart pumps blood through arteries (away from heart), to capillaries (where exchange happens in tissues), and back through veins (toward heart).
2
To pump blood around the body
The heart is a muscular pump that contracts rhythmically to push blood through blood vessels to all parts of the body, delivering oxygen and nutrients.
3
True
Arteries carry blood away from the heart to the body's tissues. They have thick, muscular walls to cope with the high pressure of blood being pumped.
4
Red blood cells
Red blood cells contain haemoglobin, a protein that binds with oxygen in the lungs and releases it in the body's tissues where it is needed.
5
True
Veins carry blood at low pressure back to the heart. They have one-way valves that prevent blood from flowing backwards due to gravity.
6
Blood picks up oxygen in the lungs, Heart pumps oxygenated blood into arteries to the body, Oxygen and nutrients pass to cells through capillary walls, Blood returns to the heart through veins
Blood collects oxygen in the lungs and returns to the left side of the heart, which pumps it through arteries to the body. Capillaries deliver oxygen to cells and collect waste, then veins return blood to the right side of the heart, which sends it to the lungs again.
7
Muscles need more oxygen, so blood must flow faster
During exercise, muscles work harder and need more oxygen and glucose for energy. The heart beats faster to deliver more oxygenated blood to meet this demand.
8
z1: Right atrium; z2: Left atrium; z3: Right ventricle; z4: Left ventricle
The heart has four chambers: two atria (top, receive blood) and two ventricles (bottom, pump blood out). The left ventricle has the thickest wall as it pumps blood to the whole body. In a diagram of a person facing you, the patient's right side is on your left.
9
It must pump blood all the way around the body at high pressure
The left ventricle pumps oxygenated blood to the entire body - all the way to your toes and back. This requires much more force than the right ventricle, which only pumps to the nearby lungs.
10
True
True. A high-salt diet can increase blood pressure, raising the risk of heart disease.