Circulation 8 th grade study guide By the 8 th grade science class.

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

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.

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.

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.

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

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

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

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.

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.

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

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.

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.