AP Biology Circulatory System

open circulatory system

circulatory fluid resides in sinuses (cavities), blood not confined to vessels; is in direct contact with body tissues

closed circulatory system

circulatory fluid resides in vessels (confined to these structures); more efficient blood flow allows for a more active lifestyle

plasma

liquid medium in which cells are suspended, transport medium

formed elements

erythrocytes (RBC), leukocytes (WBC), thrombocytes (platelets)

erythrocytes

red blood cells, contains hemoglobin (Hb) which transports respiratory oxygen

leukocytes

white blood cells, function in defense against infection

thrombocytes

platelets, nucleated cellular fragments that function in clotting

arteries

thick-walled, elastic vessels that carry oxygenated blood away from the heart to body tissue

capillaries

thin walled vessels of one epithelial layer; facilitates diffusion of materials between blood & interstitual fluid surrounding cells

veins

thinner, less elastic than arteries, carry deoxygenated blood from tissue back to the heart, contains valves to prevent the back flow of blood

lymph vessels

absorb ICF (lost 1%) at capillary beds to become lymph, ultimately returned to bloodstream;

interventricular septum

rigid muscular wall dividing the right & left sides of the heart to prevent oxygen rich & oxygen poor blood form mixing

atria

thin walled collecting chambers receiving venous blood from body systems

ventricles

muscular pumping chambers that receive blood from the atria & pump it to body systems

diastole

relaxation phase, atria & ventricles fill with blood (.4 seconds)

systole

pumping phase, atria then ventricles contract, sending blood to body systems

cardiac output

amount of blood that the left ventricle pumps per minute (stroke volume x heart rate)

blood pressure

force exerted against arterial walls during systole and diastole

systematic circulation

circulation of oxygenated blood from the left heart to the body systems

pulmonary circulation

circulation of deoxygenated blood from the right heart to the lungs and back to the left heart to a second pumping