• Co2 diffuses from tissue into blood stream
• 7% is carried as co2 in plasma
• 70% gets carried into red blood cells
• Co2 is reacted with water into carbonic acid which then dissociates into hydrogen ions and bicarbonate ions (which leaves the cell ) o Hemoglobin picks up hydrogen ions so pH of blood doesn’t change
• 23% is picked up by hemoglobin directly and then becomes a compound called carbaminohemoglobin
• Co2 then gets carried to lungs, bicarbonate goes back into the red blood cells reacts with H+ back into carbonic acid and then back into Co2 and water.
• The Co2 then exits the cells to be released out of the lungs
Open circulatory system (arthropods, mollusks, etc.)
• No separation between interstitial fluid and blood the mixture is called hemolymph
• Heart pumps blood into sinuses, which surround organs.
• Muscle contractions move blood back to heart.
• Ostia leads from sinuses back to heart
Closed circulatory system (mammals, earthworms, etc.)
• Blood never leaves vessels
• True separation between blood and interstitial fluid
• Better transportation of oxygen which means can move for longer (greater endurance)
• Heart o In thoracic cavity (about size of fist and weighs about a pound) o Contracts so it is subjected to friction o Because of this it is surrounded by pericardium (fluid filled sac) which reduces friction o Septum divides heart into two sides o Right side receives deoxygenated blood and pumps to lungs o Left side receives oxygenated blood from lungs and pumps to rest of body o Separated into upper and lower chambers o Atria are smaller because they only pump blood to ventricles o Ventricles pump blood to lungs or rest of body o Valves that separate atria from ventricles are atrioventricular valves (bi and tri-cuspid) o Blood pressure keeps valves closed o Semilunar valves separated ventricles from blood vessels