1. The Circulatory System p. 45

3. The Heart The heart is responsible for pumping blood around your body.
At rest, it usually beats around 70 beats per minute.
Each “beat” is really a squeeze that pushes blood through your blood vessels.

5. Inside the Heart
Inside the heart is divided into 4 sections called “chambers”.
The top two chambers are called the left and right atrium.
The bottom, larger chambers are called left and right ventricles. A V

6. Vessels
An artery carries blood AWAY from the heart. (Usually has bright red blood with lots of oxygen)
A vein carries blood back TOWARDS the heart. (Usually after the oxygen has been used up)
Capillaries connect veins and arteries.

7. Arteries and Veins

8. Arteries and Veins

9. Blood
Red blood cells:
which carry oxygen, are red due to the iron content.
(This is why your blood looks red.)
Hemoglobin is the protein that is in a red blood cell that allows the oxygen to stick to it.
White blood cells:
Fight off infection inside your body.

10. Blood cells

11. Platelets make up the third part of the blood
Platelets make up the third part of the blood. Platelets allow blood to clot and form scabs! Plasma is the clear liquid that makes up the rest of the blood.

12. Double loop
Blood must be pumped to the lungs to get filled with oxygen, then return to the heart.
This oxygen rich blood is then pumped out to the rest of the body where the oxygen gets used.
This means that our heart is actually a “double loop”- one loop to the lungs, one loop to and from the body.

13. Path of Blood
Starting at your big toe:
1. Deoxygenated Blood flows in veins to the heart, enters the right atrium.
2. The right atrium pushes blood into right ventricle.
3. The right ventricle pushes blood to the lungs and passes through capillaries exchanging CO2 for O2.
4. Coming back from the lungs the oxygenated blood enters the left atrium.
5. The left atrium pushes blood to the left ventricle.
6. The left ventricle squeezes and pushes blood through the aorta out to the body.

14. Link to animation: http://www. teachersdomain