The Circulatory System Lesson 8 February 9-10th, 2010

The Circulatory System Blood carries oxygen and food to the cells. It carries carbon dioxide and other wastes away from the cells. The job of the circulatory system is to move the blood throughout your body.

Parts of the circulatory system 1. Heart – Muscle that pumps blood 2.Arteries – Blood vessels that carry blood away from the heart to body cells 3. Veins – Blood vessels that carry blood back to the heart 4. Blood – Carries nutrients, oxygen, carbon dioxide and waste to and from cells.

Questions: Which vessels carry blood away from the heart? Which vessels carry blood to the heart?

How does the circulatory system work? The heart squeezes and relaxes to pump blood. For the following diagram use the numbers and arrows to follow the path that blood takes.

How does the circulatory system work? The heart gets oxygen rich blood from the lungs. The arteries take the blood away from the heart to the body cells Veins return blood from the body cells to the heart The blood is them pumped through an artery to the lungs to get more oxygen.

http://www.youtube.com/watch?v=PgI80Ue-AMo

Questions: Where do arteries get oxygen? Where do veins get carbon dioxide? When you exercise your heart rate increases. How does this help your respiratory system? Germs can enter the blood through a break in the skin, such as a scratch. Why is it important to properly bandage cuts or breaks in the skin?

Heart Rate and Blood Pressure

Your heart is a pump. When it squeezes, it pushes blood through the arteries. The blood is forced out of your heart under pressure. You can feel this rush of blood when you check your pulse. Your pulse measures your heart rate. Your heart rate is the rate at which your heart beats. It is measured in beats per minute.

Heart rate Measure your heart rate using a stopwatch. Find your pulse on the side of your neck. Use your middle finger and ring finger Then count the beats in one minute

Blood pressure The force the heart uses to pump blood all over the body is called Blood Pressure. Use a blood pressure cuff to measure blood pressure.

Blood pressure When you take a blood pressure reading, you get two numbers, such as 120/80. You say “120 over 80”. The two numbers show the blood pressure at two different parts of your heart’s pumping cycle.

Your heart takes turns squeezing and then relaxing. When the heart squeezes to pump blood, blood pressure rises. This gives the first number called systolic pressure. When the heart relaxes, blood pressure drops. This gives the second number, called diastolic pressure.

Questions: + blood pressure lab