 Provides cells with oxygen and nutrients and removes wastes  Includes the heart, several kilometers of blood vessels, and blood

 Diffusion: material moves to area where there is less of it (no energy needed)  Active transport: uses energy to move material to an area even though there might already be a lot of that material there

 Carry blood to and from the heart  Blood moving away from the heart: full of oxygen and nutrients  Blood moving back to the heart: full of carbon dioxide and wastes

 Like a one-way street: blood only moves in one direction  3 types of blood vessels: can you name them?  Hint: one carries blood to heart, one carries blood away from heart, and one connects them

 Arteries: carry blood away from the heart  Thick, elastic walls  Veins: carry blood back to the heart  Capillaries: microscopic blood vessels that connect arteries and veins  Walls are only one cell thick (allows for nutrients and oxygen to diffuse out of capillaries and carbon dioxide and waste to diffuse back into capillaries)  Every cell is within 0.15mm of a capillary

 Made of four compartments (chambers)  Upper chambers: atriums  Lower chambers: ventricles  Blood flows from left atrium to left ventricle, and right atrium to right ventricle, but not between right and left chambers  One side has oxygen-rich blood and one side has blood with very little oxygen

 Coronary circulation  Pulmonary circulation  Systemic circulation

 All are controlled by the beating of your heart  One heartbeat: both atriums contract at same time, then both ventricles contract at same time  Blood flow: one atrium to one ventricle to an artery

 Flow of blood to and from tissues of the heart  The heart, like any other muscle, needs blood vessels  Supply it with nutrients and oxygen  Remove wastes and carbon dioxide  If coronary arteries become damaged, it can lead to heart attacks

 Flow of blood through the heart, to the lungs, and back to the heart  Blood returning to the heart enters the right atrium (think Right = Return)  Enters through 2 main veins: superior and interior vena cava  Superior vena cava: returns blood from head and neck  Inferior vena cava: returns blood from lower body  Blood is high in carbon dioxide and low in oxygen  Right atrium contracts and forces blood down into right ventricle

 Right ventricle contracts, forcing blood out of heart and into pulmonary artery  Pulmonary artery carries blood to lungs, where is exchanges carbon dioxide for oxygen  Pulmonary vein carries oxygen-rich blood from lungs back to heart, where is enters through left atrium  Left atrium contracts and forces blood down into left ventricle  Left ventricle contracts and forces blood out of heart and into aorta (main artery)

 Oxygen-rich blood flows to organs and body tissues, and oxygen-poor blood returns to the heart  Largest of the three parts of the circulatory system  Oxygen-rich blood exits left ventricle, enters aorta, and is taken throughout body by arteries and capillaries  Oxygen-poor blood is taken back to heart by veins, then superior and inferior vena cava take this blood to heart’s right atrium

 Your blood puts pressure on the walls of the blood vessels too  Blood pressure: the force of the blood on the walls of the blood vessels  Highest in arteries, lowest in veins  Measured in large arteries by 2 numbers  Systolic: top number, when ventricles contract and blood is pushed out of heart  Diastolic: bottom number, occurs as ventricles fill with blood just before they contract  Sample blood pressure: 120 over 80

 Your body wants to keep it normal to keep blood reaching all organs  When blood pressure changes and falls out of a normal range, nerves send messages to the brain to adjust this by speeding up or slowing down the heart rate

 Also called cardiovascular disease  Common types of heart disease:  Hypertension  Heart failure  Stroke  Athersclerosis  Heart attack

 With a partner, you will research one of the common heart diseases on the previous slide  Be prepared to explain to the class what exactly happens to the heart, what may cause it, what risks are associated, and what can be done to avoid it  Other factors to consider: is it related to another disease? Does it cause death or another illness? How many people does it kill annually?

 Atherosclerosis: fatty deposits build up on walls of arteries, and blood can’t get through  Comes from eating foods high in cholesterol and saturated fats  See p. 236

 Hypertension: high blood pressure for an extended period of time  Puts extra strain on your heart to get nutrients and oxygen to all the body’s cells  Can be caused by atherosclerosis