Circulation 8 th grade study guide

1. Circulation8th grade study guide By the 8th grade science class.

2. Movement of materials • Cardiovascular system- heart, blood vessels, and blood. • Cardiovascular system carries needed substances to cells and carries waste away. • Disease fighters- white blood cells

3. Heart • Heart- is a hollow muscular organ that pumps blood though out the body. • The heart beat pushes blood through the cardiovascular system. • Atrium- the two upper chambers that receive blood. • Ventricle- pumps blood out of the heart and they are the 2 lower chambers. • Valve- a flap of tissue that prevents blood from flowing backwards.

4. How the heart works • 2 main phases • Phase 1- the heart muscle relaxes and the heart fill with blood. • Phase 2- the muscle contracts and pumps blood forward.

5. Regulation of heartbeat • Pacemaker- a group of cells in the right atrium that sends out signals that make heart muscle contract. • Oxygen- being detected by the pacemaker and it tells the heart how fast to pump.

6. 2 loops • Arteries- carries blood away. • Capillaries- substances are exchanged between blood and body cells. • Veins- carry blood back to heart. • First loop-blood goes from the heart to lungs and back to heart • Second loop-blood goes from heart to the body and back to the heart • Aorta-the largest artery in the body

7. Blood vessels • Coronary arteries-carries blood to the heart • Artery structure-3 layers, make it strong and flexible so they can withstand enormous pressure • Pulse-feeling the artery rise and fall • Regulating blood flow-involuntary muscles relax and contract to push blood

8. Blood vessels • Capillaries-materials like oxygen and glucose pass through thin walls into body cells • Diffusion-the process by which molecules go from high to low concentration • Veins-after blood moves through capillaries it enters large blood vessels called veins

9. Blood Pressure • Pressure- The force that something exerts over a given area. • Blood pressure is caused by the force with which ventricles contract. • A sphygmomanometer is used to measure blood pressure.

10. Blood and Lymph • Plasma- The liquid part of the blood. • 4 parts of blood- red blood cells, white blood cells, plasma, and platelets. • Red blood cells- They deliver oxygen to cells. • Hemoglobin- A protein that bonds chemically to oxygen molecules.

11. Blood and Lymph • White Blood Cells-disease fighters. • Platelets-form blood clots. • Fibrin-chemical that traps blood cells. • Blood Transfusion-moving blood from 1 person to another. • Marker Molecules determine blood type for safe transfusions

12. The lymphatic system • Lymphatic system- a network of vessels that return fluid to the blood stream. • Lymph- fluid inside the lymphatic system. • Lymph nodes- small knobs of tissue that trap bacteria and other micro organisms that cause disease.

13. Cardiovascular health • Atherosclerosis- a condition where a artery wall thickens, because of build of fatty materials. • Heart attack- blood flow to part of the heart muscle is blocked. • Diet, exercise, medication, not smoking, and surgery can reduce chances of these diseases. • Hypertension- blood pressure is always too high.