The circulatory system functions to deliver needed materials to cells, remove waste from cells, and fight off infections. It consists of the heart with four chambers that pump blood through two pathways - the pulmonary circuit which sends blood to the lungs to exchange gases and the systemic circuit which pumps oxygenated blood to the body. Blood vessels including arteries, veins, and capillaries transport blood and allow for the exchange of materials between blood and body cells. The heart beat and pulsing blood flow are controlled to maintain healthy blood pressure levels, while diseases can occur if the circulatory system is compromised.

1. Circulatory System6th Grade Science

2. I. FunctionA. Deliver needed materials to cellsB. Removing waste from cellsC. Fighting off infection

3. II. PartsHeart1. Muscle to pump blood2. Four chambersi. 2 Atrium (top)ii. 2 Ventricle (bottom)3. Valves to separate flow

4. 4. PathwayFrom BodyFrom LungRALARVLVTo LungTo Body

6. 4. Pathwayii. Pulmonary Circuita. Send CO2 blood from right side heart to lungsb. Lungs remove CO2 and replace with O2c. Return to left side of heart

7. 4. Pathwayiii. Systemic Circuita. Send O2 blood from left side heart to bodyb. Cells remove O2 and replace with CO2b. Return to right side of heart

8. 5. Heart Beati. Top heart contracts togethera. Valves close (Lub)ii. Bottom heart contracts togethera. Larger Valves close (Dub)

9. B. Blood VesselsArteriesCarry blood away from heartVeinsCarry blood toward the heartCapillariesi. Where body exchanges materials

10. 4. Controlling blood flowi. Pulsing blood flowa. Heart beats (high number) - topb. Heart relaxes (low number) – bottomc. Healthy numbers 120/80

11. ii. Veinsa. Valves to help return bloodb. Muscles help return blood

12. III. DiseasesA. AtherosclerosisB. Heart AttackC. Hypertension 140/90