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Unit 1: Cells and Systems Sec2on 2.3 The Circulatory and Respiratory Systems Circulatory System • The transporta,on network for oyxgen and carbon dioxide to and from the cells. • Made up of three components: o Blood o Vessels o Heart Blood • about 5 L in the human body 55% Plasma 45% Cells Plasma • clear, yellowish fluid • Made up of: a) water b) proteins and minerals c) dissolved salts Blood Cells 1. Red Blood Cells • contain iron (gives blood its red colour) • hemoglobin carries oxygen from the lungs to the body cells and carbon dioxide from body cells to lungs. • disc-‐shaped for increased surface area • manufactured in bone marrow, the liver, and spleen. 2. White Blood Cells • guard fight infec,ons and foreign substances. • work with the immune system 3. Platelets • important for blood cloLng • stop bleeding and seal wounds by thickening blood so a scab forms. The Heart: The Pump • Four chambers: – Two atria -‐ upper receiving chambers. – Two ventricles-‐ lower pumping chambers. • Right Atrium -‐ receives deoxygenated blood from the body and emp,es into the right ventricle. • Right Ventricle -‐ receives deoxygenated blood from the right atrium and pumps it to the lungs. • LeJ Atrium -‐ receives oxygenated blood from the lungs and emp,es into the leN ventricle • LeJ Ventricle -‐ receives oxygenated blood from the leN atrium and pumps it to the body cells. • Valves -‐ control the direc,on of blood movement in the heart, preven,ng backflow. Vessels: The Transporta2on Network Major Blood Vessels Aorta -‐ transports oxygenated blood from the leN ventricle to body ,ssues. Superior Vena Cava -‐ transports deoxygenated blood from the upper parts of the body to the right atrium. Inferior Vena Cava -‐ transports deoxygenated blood from the lower parts of the body to the right atrium. Pulmonary Artery -‐ transports deoxygenated blood from the right ventricle to the lungs. Pulmonary Vein -‐ transports oxygenated blood from the lungs to the leN atrium. Smaller Blood Vessels Arteries • carry blood away from the heart to the body’s cells • thick-‐walled and elas,c • most carry oxygenated blood (excep,on: pulmonary artery). Veins • carry blood to the heart • most carry deoxygenated blood (excep,on: pulmonary vein). Capillaries • network of ,ny blood vessels that travel to each of the cells. • walls are thin to allow exchange of gases and nutrients.
