KEY CONCEPT The respiratory and circulatory systems bring oxygen and nutrients to the cells.

1. KEY CONCEPT The respiratory and circulatory systems bring oxygen and nutrients to the cells.

2. Oxygen-poor blood Oxygen-rich blood The respiratory and circulatory systems work together to maintain homeostasis. • The circulatory system transports blood and other materials. • brings supplies to cells • carries away wastes • separates oxygen-poor and oxygen-rich blood

3. sinus nose mouth epiglottis trachea lungs • picks up oxygen from inhaled air • expels carbon dioxide and water • The respiratory system is where gas exchange occurs.

4. alveoli bronchiole The respiratory system moves gases into and out of the blood. • The lungs contain the bronchi, bronchioles, and alveoli. • Millions of alveoli give the lungs a huge surface area. • The alveoli absorb oxygen from the air you inhale.

5. Air inhaled. Air exhaled. Muscles and rib cage relax. Muscles contract and rib cage expands. Diaphragm flattens and moves downward. Diaphragm relaxes and rises. • Breathing involves the diaphragm and muscles of the rib cage. • Air flows from areas of high pressure to low pressure.

6. veins arteries The circulatory system moves blood to all parts of the body. • The system includes the heart, arteries, veins, and capillaries. • heart pumps blood throughout body • arteries move blood away from heart • veins move blood back to heart • capillaries get blood to and from cells

7. transporting blood, gases, nutrients • There are three major functions of the circulatory system. • collecting waste materials • maintaining body temperature

8. KEY CONCEPT The heart is a muscular pump that moves the blood through two pathways.

9. NORMAL HUMAN HEART The tissues and structures of the heart make it an efficient pump. • Cardiac muscle tissue works continuously without tiring.

10. pulmonary valve aortic valve left atrium right atrium mitral valve left ventricle tricuspid right ventricle septum • Valves in each chamber prevent backflow of blood. • The heart has four chambers: two atria, two ventricles. • Muscles squeeze the chambers in a powerful pumping action.

11. SA node VA node • The heartbeat consists of two contractions. • SA node, or pacemaker, stimulates atria to contract • AV node stimulates ventricles to contract

12. 1 3 2 4 • Blood flows through the heart in a specific pathway.

13. oxygen-poor blood enters right atrium, then right ventricle • Blood flows through the heart in a specific pathway. • right ventricle pumps blood to lungs • oxygen-rich blood from lungs enters left atrium, then left ventricle • left ventricle pumps blood to body

14. The heart pumps blood through two main pathways. • Pulmonary circulation occurs between the heart and the lungs. • oxygen-poor blood enters lungs • excess carbon dioxide and waterexpelled • blood picks up oxygen • oxygen-rich blood returns to heart

15. Systemic circulation occurs between the heart and the rest of the body. • oxygen-rich blood goes to organs, extremities • oxygen-poor blood returns to heart • The two pathways help maintain a stable body temperature.

16. KEY CONCEPT The lymphatic system provides another type of circulation in the body.

17. heart lymph nodes lymph vessels Lymph is collected from tissues and returned to the circulatory system. • The lymphatic system collects fluid that leaks out of the capillaries. • Lymph vessels have valves to prevent backflow. • Lymph nodes filter the lymph and destroy foreign matter. • Lymph vessels return cleaned fluid to the circulatory system. • If lymph vessels or nodes are damaged, lymph collects in an area.

18. tonsils thymus spleen The lymphatic system is a major part of the immune system. • Structures in the lymphatic system help fight disease. • tonsils filter bacteria and viruses • thymus develops white blood cells • spleen filters lymph, contains immune cells • Lymphocytes help destroy pathogens, parasites, and foreign matter.