The Lungs

Meet the lungs

Every time you take a breath, oxygen makes it way into your lungs. Follow along on that journey! Rishi is a pediatric infectious disease physician and works at Khan Academy.

People and plants

Learn more about photosynthesis and cellular respiration through a classic story: Jack and the Beanstalk. Rishi is a pediatric infectious disease physician and works at Khan Academy.

The Bronchial Tree

Follow the path of an oxygen molecule as it makes its way from your mouth down to an alveolus! Rishi is a pediatric infectious disease physician and works at Khan Academy.

Inhaling and Exhaling

Find out exactly why air goes in and out of the lungs. Rishi is a pediatric infectious disease physician and works at Khan Academy.

How does Lung Volume Change?

Learn about how muscle contraction and lung recoil actually help the lungs change their volume with every breath! Rishi is a pediatric infectious disease physician and works at Khan Academy.

The Lungs and Pulmonary System

The pulmonary system including the lungs, larynx, trachea, bronchi, bronchioles, alveoli and thoracic diaphragm

Alveolar Gas Equation - Part 1

Find out how to calculate exactly how much oxygen is deep down inside your lungs! Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Alveolar Gas Equation - Part 2

Find out how to calculate exactly how much oxygen is deep down inside your lungs! Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

O2 and CO2 solubility

Get an intuition for why carbon dioxide is so much more soluble than oxygen when it goes into water. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Henry's law

Explore the relationship between partial pressure of a gas and the concentration of the gas molecule within a liquid. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Graham's Law of Diffusion

Find out whether oxygen or carbon dioxide has a higher rate of diffusion (Hint: It pays to be small!). Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Fick's Law of Diffusion

Learn all of the different ways to maximize the amount of particles that diffuse over a short distance over time. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Oxygen Movement from Alveoli to Capillaries

Watch as a molecule of oxygen makes its way from the alveoli (gas layer) through various liquid layers in order to end up in the blood. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Peripheral Chemoreceptors

Find out how the your body uses special cells that are peripheral to the brain (outside the brain) to sense levels of O2, CO2, and pH. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Central Chemoreceptors

Find out how the your body uses special cells that are central to the brain (inside the brain) to sense levels of CO2 and pH. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

The Respiratory Center

Find out how the respiratory center collects information from all over the body and then helps regulate your breathing. Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.

Sneeze, Cough, and Hiccup

Learn how our brain receives information from mechanoreceptors and then responds by controlling muscles in a well-coordinated system, and how all of this can lead to a sneeze, a cough, or even a hiccup! Rishi is a pediatric infectious disease physician and works at Khan Academy. These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read or seen in any Khan Academy video.