1. Unit A Chapter 3 Review

2. When you hold your breath, your brain sends a message to the diaphragm and rib muscles telling them to breathe. Why is this message sent from the brain?

3. because carbon dioxide is building up in the blood.

4. Which type of blood vessel takes blood from the cells back to the heart?

5. vein

6. Around the wall of each air sac in the lungs is a web of …

7. capillaries

8. When does digestion begin?

9. when the teeth grind the food

10. How does food move through the esophagus?

11. Rings of muscles squeeze food down the esophagus.

12. Which organs send chemicals to the small intestine to help digest food?

13. pancreas and liver

14. What is the role of villi in the small intestine?

15. The villi provide more surface area to absorb food.

16. The transportation system of the body is …

17. circulatory system

18. Which system in the human body is involved in removing wastes from the body?
urinary
nervous
skeletal
circulatory

19. urinary

20. Name three tasks the kidneys perform.

21. Clean the blood
Regulate the level of salt in the blood
Control the level of water in the blood

22. Which organ stores a mix of wastes and water until the mix of waste and water is ready to leave the body?

23. Urinary bladder

24. Which type of cell will the body make in greater numbers in response to an infection?

25. white blood cells

26. What is the thick, sticky fluid that traps germs and other things that may be in the air?

27. mucus

28. Which part of your blood has the job of clotting your blood?

29. platelets