Khan Academy Static

3B: With every beat, the heart pumps blood throughout the body through an intricate system of blood vessels to provide oxygenation to tissues - from about 4 weeks after conception until the day you die. Over your lifetime, it will pump about 175 million liters of blood (that’s only the amount of water that falls over the Niagara in a few minutes). This little pump in the middle of your chest is only the size of a clenched fist (if you’re an adult), and yet it does so much.

15011_Thermoregulation_in_the_circulatory_system.html

15009_Resistance_in_a_tube.html

15005_Two_circulations_in_the_body.html

15003_Layers_of_the_heart.html

15006_Lub_dub.html

15010_Putting_it_all_together_Pressure_flow_and_resistance.html

15002_Meet_the_heart_.html

15008_Arteries_vs_veins_what_s_the_difference_.html

15007_Layers_of_a_blood_vessel.html

15004_Flow_through_the_heart.html