Summary questions 1. State the three main roles of the circulatory system.
2. Copy and complete the sentences.
There are three types of blood cell. Oxygen is transported by the ____________ blood cells, which contain ____________. The main function of ____________ blood cells is to protect the body from ____________. Platelets are ____________ of cells that help the blood to ____________.
____________ transports the blood cells around the body, along with dissolved substances and ____________.
3. Explain the role of plasma in the blood.
4. Outline two features of each of the three types of blood vessels: a. artery b. vein c. capillary
5. Give one reason for each of the following statements: a. Arteries have thick walls. b. Veins have valves. c. Capillaries have thin walls.
6. Explain why the pulse rate is the same as the heart rate.
7. Outline two potential causes for the following changes in heart rate: a. heart rate speeds up b. heart rate slows down
8. Label the parts of the heart labelled A, B and C in Fig. 7.11.