https://www.khanacademy.org/science/biology/human-biology/circulatory-pulmonary/v/circulatory-system-and-the-heart 2024-05-06T19:22:43.24334365Z Circulatory system and the heart Hemoglobin, found in red blood cells, absorbs oxygen, increasing the diffusion gradient. This process encourages oxygen to cross the membrane. Hemoglobin is contained within red blood cells to prevent blood from becoming too thick. The blood flows from the heart to the lungs via the pulmonary artery, gets oxygenated, and returns to the heart via the pulmonary vein. The oxygenated blood is then pumped to the rest of the body. Sal Khan video https://cdn.kastatic.org/googleusercontent/QQ3kDKa7ct44EUTcIZwN312V1-RrEgNJruMr8OSIco3MqyTZIfh9-PUfndLKhLpV7f1nQNq58WmnIysS_iLr1Bd7Dw Circulatory system and the heart Hemoglobin, found in red blood cells, absorbs oxygen, increasing the diffusion gradient. This process encourages oxygen to cross the membrane. Hemoglobin is contained within red blood cells to prevent blood from becoming too thick. The blood flows from the heart to the lungs via the pulmonary artery, gets oxygenated, and returns to the heart via the pulmonary vein. The oxygenated blood is then pumped to the rest of the body. https://cdn.kastatic.org/ka-youtube-converted/QhiVnFvshZg.mp4/QhiVnFvshZg.mp4 897 Heart and its working https://www.khanacademy.org/science/health-and-medicine/circulatory-system/circulatory-system-introduction/v/flow-through-the-heart 2020-09-09T23:28:12Z Flow through the heart Learn how blood flows through the heart, and understand the difference between systemic and pulmonary blood flow. Rishi is a pediatric infectious disease physician and works at Khan Academy. Rishi Desai video https://cdn.kastatic.org/googleusercontent/oZ6EhbCXlLF8nqwCrKPR1Z4ftBWhk54hdKa9fGwBCm5IRu2rqouGgpU9MTWst9rAQJyZW_7WHiSxn0aIX6dVYHZr Flow through the heart Learn how blood flows through the heart, and understand the difference between systemic and pulmonary blood flow. Rishi is a pediatric infectious disease physician and works at Khan Academy. https://cdn.kastatic.org/ka-youtube-converted/7XaftdE_h60.mp4/7XaftdE_h60.mp4 471 Heart and its working https://www.khanacademy.org/science/health-and-medicine/circulatory-system/circulatory-system-introduction/v/lub-dub 2020-09-09T11:23:52Z Lub dub Ever wonder why the heart sounds the way that it does? Opening and closing of heart valves makes the heart rhythm come alive with its lub dub beats... Rishi is a pediatric infectious disease physician and works at Khan Academy. Rishi Desai video https://cdn.kastatic.org/googleusercontent/H-eK4hgL6f_a6509l4oPFD4JwZEzNoXexVyXLC19Us8P2YM3KpmzOHgFXDRY4fqToIrrhPqeIocwUN30mLsYRJjJ3g Lub dub Ever wonder why the heart sounds the way that it does? Opening and closing of heart valves makes the heart rhythm come alive with its lub dub beats... Rishi is a pediatric infectious disease physician and works at Khan Academy. https://cdn.kastatic.org/ka-youtube-converted/-4kGMI-qQ3I.mp4/-4kGMI-qQ3I.mp4 590 Heart and its working https://www.khanacademy.org/science/cambridge-o-level-biology-cie/x2a084a90105205d2:transport-in-humans/x2a084a90105205d2:heart/v/checking-pulse-ur 2025-08-08T00:24:37.843818748Z Checking pulse Created by Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Checking pulse Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/oPCj9nvHUaM.mp4/oPCj9nvHUaM.mp4 69 Heart and its working https://www.khanacademy.org/science/cambridge-o-level-biology-cie/x2a084a90105205d2:transport-in-humans/x2a084a90105205d2:introduction-to-the-circulatory-system/e/transportation-in-human-beings 2026-03-05T08:50:45.400692349Z Transportation in human beings Let's practice some questions related to transportation in human beings saiyem exercise