pulmonary and systemic circuits

what is the pulmonary circuit made of

• pulmonary trunk and arteries that deal only with the heart and lungs

pulmonary arteries and veins

• only artery in the body that carries deoxygenated blood and the only vein in the body that carries oxygenated blood

• function: the arteries bring deoxygenated blood form the right side of the heart to the lungs to get oxygen for the body, while the veins return oxygenated blood from the lungs to the left atrium of the heart

pulmonary circuit

• path that goes to and from the lungs

• from the right ventricle through the pulmonary trunk to the pulmonary arteries to the lung capillaries to the pulmonary veins to the left atrium

• carries carbon dioxide filled blood to the lungs for cleaning

systemic circuit

• path from left ventricle to body back to right atrium of heart

• carries CO2 rich blood to the body tissues

• returns CO2 filled blood to the heart

cross sectional area definition

• cross sectional area of the blood vessels = sum of the cross sectional area of all blood vessels of one type

• they have a major effect on blood flow

what happens when cross sectionals increase - velocity of blood

the velocity of the blood decreases from arteries to arterioles to capillaries and increases in venules and veins

what happens when cross sectionals increase - blood pressure

• as CSSA increases, blood pressure decreases

• Once blood pressure is lost in the capillaries it cannot be regained even if CSA of venules and veins increases.