Download Lesson 14

Lesson 14- The Pumping Heart
Circulatory System: the function is to transport oxygen and
nutrients to the cells of the body
Heart: the main organ of this system, approx. the size of your
fist, has 4 chambers
Atria: the top two chambers of your heart
Ventricles: the bottom two chambers of your heart
Septum: divides your heart into a right and left side
Valves: prevent blood from flowing in the wrong direction, make
sure the blood flows only in one direction
Arteries: carry blood away from the heart
Veins: carry blood to the heart
Capillaries: connect arteries to veins
Vena Cava: see diagram
Aorta: largest artery in body
Pulmonary Circulation: pulmonary means lungs- the circulation of
blood from the right side of the heart to the lungs (where blood
picks up oxygen) then to the left side of the heart
Systemic Circulation: the circulation of blood from the left side
of the heart to the entire body back to the right side of the
heart (delivering oxygen to the cells of body)
Closed Circulatory system: a system of blood vessels that carry
blood throughout your body
Reflection Questions:
1. What causes the “lub-dub” sound in the heart? As the
ventricles contract, the valves between the atria and
ventricles close. This sets up the vibrations we hear as the
“lub” sound of the heart. When the atria contract, the
valves between the ventricles and outgoing arteries close.
This sets up the vibrations we hear as the “dub” sound of
the heart.
2. Why is the heart considered a double pump? The right side
of the heart pumps blood to the lungs and the left side
pumps blood to the rest of the body. In addition, the atria
contracts in unison to pump blood into the ventricles. Then
the ventricles contract to pump blood into the outgoing
arteries.
3. What is the function of the valves in the heart? The valves
prevent the backflow of blood in the heart. If a valve is
faulty, there may be a backflow of blood through the valve.
This is called a heart murmur, which can be heard through a
stethoscope.
4. What does a “closed” circulatory system mean? Human
blood is confined within vessels.