Heart and Cardiac cycle

Across

• 1. When the ventricles contract and the blood is forced into the aorta/pulmonary artery (11, 7)
• 4. These carry blood to the heart (5)
• 5. These chambers have less muscular walls as they only have to pump blood inside the heart (5)
• 6. These carry blood away from the heart (8)
• 7. The smallest blood vessels, where metabolic exchange occurs (11)
• 8. This chamber has the thickest and most muscular walls (4, 9)
• 9. These stop blood flowing back into the heart (9, 6)