Circulatory System

Circulatory System The circulatory system in your body is basically a system of transportation. It carries blood to every body part, and that blood carries oxygen, delivers nutrients, collects waste materials, and fights germs.

The following internet sites can help you learn more about your circulatory system which will, by the time you are 70 years old, pump about 180 million quarts of blood through your body.

Circulatory System

Your circulatory system helps regulate your temperature. When you are hot, capillaries just beneath your skin grow slightly wider to allow more blood to be near the surface of your skin and allow some body heat to escape. This is why your face is often red when your are very hot. When you are cold, the capillaries get slightly thinner. Less blood goes near the skin's surface, and less heat is lost. This is why very cold skin has a bluish tint. Blood also carries body heat from hotter parts of the body to cooler parts. This keeps the body at an even temperature of about 98.6 degrees Fahrenheit.

What is your largest artery called?

Veins and Arteries

Arteries have the thickest walls because they have to carry large amounts of blood at high pressure. Veins have thinner walls because the pressure inside them is lower. Capillaries have the thinnest walls because one of their functions is to allow nutrients to pass from the blood into the body's cells.

Do arteries carry blood away from or to the heart?
About how thick are the largest arteries?
About how thin are the smallest arteries? What are these thinnest arteries called?
Do veins carry blood away from or to the heart?
What are the thinnest veins called?
Why don't veins have to be as strong as arteries?
What does cold-blooded mean? Are humans cold-blooded or warm-blooded?

Circulatory System

The blood of people who have the disease called hemophilia does not have a certain clotting chemical. This means that even a small cut can bleed for a long time.

What connects arteries and veins?

Circulatory System

Have you ever had a nose bleed? The linings of your nasal passages have many blood vessels. Sometimes they break and cause a nose bleed.

Describe where your heart is located in your body.
Describe the color of the blood in your circulatory system as it relates to oxygen content.
What is the function of capillaries?

Circulatory System Amazing Facts

The red color of blood comes from the red blood cells, and they get their red color because they contain hemoglobin which is an iron-bearing red pigment.

About how many times does a heart beat during an average lifespan?
About how many blood cells die each second and how many new ones are regenerated?
About how long does it take for a red blood cell to circle the whole body?
Where do red blood cells originally come from? Where do they die?
About how many times do they circulate in the body before they die?
About how long do red blood cells live?

American Heart Association : Heart

You could lose up to a third of the blood in your body and still survive.

About how big is your heart?
In an average life time, about how many times does a heart beat?
If all of your blood vessels were laid end to end, how far would they extend?
What is the function of circulating blood?
Which organs in your body filter waste products from your blood?
In how many directions do the valves in the chambers of the heart allow blood to flow?
What makes the heart pump blood?
What does the pacemaker in your heart do? (Even though we usually associate the word "pacemaker" with an artificial replacement heart part, we all have a natural pacemaker).

Heart

Each beat of your heart makes the walls of your arteries bulge. These bulges can be felt as pulses where blood vessels run over a bone. You can take your pulse (the number of times your heart beats in a minute) at your wrist, your neck, your groin, your ankle, and the top of your foot. The wrist is a convenient place to take your pulse because the radial artery lies just below the skin and directly above the wrist bone. The cartoid artery in your neck is another easy place to feel for your pulse.

What is the septum?
What structures control the direction of blood between chambers in the heart?

Inner Body : Cardiovascular System

At any given time, 64% of your blood is flowing through your veins. 20% is flowing through your arteries and capillaries in your body. 9% is flowing through the blood vessels in your lungs, and 7% is flowing through blood vessels in your brain.

Which part of our body tells our heart to beat?

Blood

Cardiac (heart) muscle is somewhat different than normal muscle in our body. The main difference is that cardiac muscle never tires.

About how much blood do adults have?
What is the liquid substance in your blood called in which blood cells float? What is this substance made up of?

Circulatory System

Adults have about 25 trillion red blood cells.

What is the main function of white blood cells?
About how long does it take for blood to travel through the whole body?
On the diagram on this site, which kinds of blood vessels are red and which kind are blue?

Virtual Body

You will need the plugin, Shockwave, installed on your computer for this site to work at its best.

Cardiovascular System

White blood cells are much larger than red blood cells. White blood cells have a nucleus. Red blood cells and platelets have no nucleus.

If your blood vessels were strung together, how many times would they go around the world?
Your blood delivers necessary oxygen to every part of your body. How does your blood get oxygen?
What are 2 ways that your white blood cells defend you against disease?
About how much blood does a 3 year old child have in his body? How much does an adult have?
What is your heartbeat?

American Heart Association

If you bump into something, you might get a bruise. A bruise forms when the bump causes tiny capillaries under your skin to break and blood leaks under the skin. This blood under your skin usually looks black and blue. After a few days, the bruise usually turns yellow as the leaked blood is gradually broken down.

What is a myocardial infarction? What causes it?

The Yuckiest Site on the Internet

There are four blood types--A, B, AB, and O.

From the pull-down menu at the top of this page, select "Scabs and Pus". Explain how the platelets in your blood help a cut or wound to heal.

Exercise and Fitness

When you are at rest, your heart beats about 60-70 times per minute and pumps 5-6 quarts of blood a minute. If you engage in moderate exercise, your heart beats 100-120 times a minute and pumps 7-8 quarts a minute. During strenuous exercise, your heart beats 200-220 times per minute and pumps up to 30 quarts of blood per minute.

How does exercise strengthen your heart?

Why We Should Exercise

Every time your heart pumps, both pairs of valves in your heart close with a particular sound. This is what doctors are listening for when they use a stethoscope to listen to your heart.

List 5 ways that execise benefits your heart, your circulatory system, and your health in general.

Heart Quiz

Animals' hearts beat at a different rate than a human's heart. Interestingly, the bigger the animal, the slower the heart rate. An elephant's heart beats about 27 times a minute. A canary's heart beats about 1,000 times a minute!

Take this quiz about your heart and record your score.

Bibliography

Hardie, Jackie. Blood and Circulation. Rigby Interactive Library : Crystal Lake, Illinois, 1997.

Parker, Steve. Blood. Copper Beech Books : Brookfield, Connecticut, 1997.

Parramon, Merce. How Our Blood Circulates. Chelsea House: New York, 1994.

Sandeman, Anna. Blood. Copper Beech Books : Brookfield, Connecticut, 1996.

Stille, Darlene. The Circulatory System. Children's Press : New York, 1997.

Author: LINDA MOSBACKER - Email linda.mosbacker@slc.k12.ut.us