Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

The Heart As a Pump.pulmonary circuits.You will recall that the heart receives blood from both systemic and• The DEOXYGENATED BLOOD RETURNS to the right atrium of the heart FROM THESYSTEMIC CIRCUIT via the superior and inferior vena cavae. From the right atrium, theblood moves through the tricuspid valve into the right ventricle. When the right ventriclecontracts, the tricuspid valve closes and the blood is forced through the pulmonary semilunarvalve into the pulmonary trunk which divides into the right and left pulmonary arteries. Theblood flows through the pulmonary arteries to the pulmonary capillaries where it absorbsoxygen and releases carbon dioxide.• The OXYGENATED BLOOD RETURNS to the left atrium of the heart FROM THEPULMONARY CIRCUIT via the pulmonary veins. From the left atrium, the blood movesthrough the mitral (bicuspid) valve into the left ventricle. When the left ventricle contracts,the mitral valve closes, and the blood is forced through the aortic semilunar valve into theaorta and into the systemic circulation.The pumping action of the heart creates pressure on the walls of the blood vessels which can bemeasured when your blood pressure is taken. Both the systolicI and the diastolic 2 values aremeasured.1systolic blood pressure--The force with which the blood is pushing against the artery walls whenthe ventricles are contracting.2diastolic blood pressure--Thethe ventricles are relaxed.force with which the blood is pushing against the artery walls when105