2.  Functions  Transport system nutrients from digested food  all body cells oxygen from the lungs  all body cells metabolic wastes (CO 2 )  organs to be excreted hormones  target tissues  Regulates body temperature in a warm environment blood vessels dilate, allowing more heat to leave the body in a cold environment blood vessels constrict, preventing heat from escaping from the body

3.  Arteries – carry oxygenated blood away from the heart  arterioles – small arteries  thick elastic walls to withstand the pumping action of the heart  high blood pressure

4.  Capillaries – connect arterioles to venules  Walls are only one cell thick so molecules can easily diffuse across Nutrients diffuse from capillaries  body cells Wastes diffuse from body cells  capillaries  Capillaries are vey narrow; thickness of a single RBC

6.  Veins – carry deoxygenated blood back to the heart  thin walls due to low blood pressure  have valves to help prevent backflow of blood

11.  A muscular pump that propels blood through the blood vessels  Atria – two upper chambers that receive blood returning to the heart  Ventricles – two lower thick–walled chambers that pump blood away from the heart

12.  Pericardium – protective sac around the heart

13.  Vena cava – largest veins  Superior – drains blood from the upper body into right atrium  Inferior – drains blood from the lower body into right atrium  Aorta – largest artery  comes from left ventricle and branches to deliver blood to the entire body

14.  Pulmonary arteries – carry blood from the heart to the lungs  Pulmonary veins – carry blood from the lungs back to the heart

15.  Coronary arteries – delivers blood to cardiac muscle

16.  When the coronary arteries become blocked a heart attack occurs

17.  Stroke – when blood supply is cut off to the brain and an area of the brain dies.

18.  Valves – prevent the backflow of blood as it is being pumped through the heart  Named according to where they lead or how they look  Atrioventricular Valves – between the atria and ventricles tRicuspid – on the Right side bicuspid – on the left side (a.k.a. as the mitral v.)  Semilunar Valves – between the ventricles and arteries pulmonary – right ventricle  pulmonary artery aortic – left ventricle  aorta

20.  Vena cava  right atrium  tricuspid valve  right ventricle  pulmonary valve  pulmonary artery  lungs  pulmonary veins  left atrium  bicuspid valve  left ventricle  aortic valve  aorta

21.  The left side of the heart pumps oxygen–rich blood out to the body through a network of arteries  Oxygen–poor blood is returned to the right side of the heart through veins.

22.  The right side of the heart pumps oxygen– poor blood through the pulmonary arteries to the lungs.  Gas exchange (release of C0 2 and and pick up of O 2 ) occurs in the lungs.  The oxygen–rich blood then returns to the left side of the heart through pulmonary veins

23.  In the pulmonary circuit the oxygen content of the vessels is reversed!  The pulmonary artery carries oxygen–poor blood away from the heart to the lungs  The pulmonary vein carries oxygen–rich blood from the lungs back to the heart

24.  Sinoatrial (SA) node  acts as the pacemaker for the heart  cluster of cells located in the upper wall of the right atrium  sends a rhythmic electrical stimulus causing both atria to contract pushing blood into the ventricles  Atrioventricular (AV) node  in between the atria  causes contraction of the ventricles just after the atria contract pushing blood out of the heart