Correction to "Sodium-potassium pump" video. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/health-and-medicine/human-anatomy-a… Missed the previous lesson?

How a sodium potassium pump can maintain a voltage gradient across a cell or neuron's membrane. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/test-prep/mcat/cells/transport-across-a-cel… Missed the previous lesson?

Neurons (or nerve cells) are specialized cells that transmit and receive electrical signals in the body. Neurons are composed of three main parts: dendrites, a cell body, and an axon. Signals are received through the dendrites, travel to the cell body, and continue down the axon until they reach the synapse (the communication point between two neurons). Created by Sal Khan.

Hemoglobin and its role in the circulatory system. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/health-and-medicine/human-anatomy-a… Missed the previous lesson?

Introduction to the circulatory system and the heart. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/health-and-medicine/human-anatomy-a… Missed the previous lesson?

Oxygen uptake by hemoglobin in red blood cells. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/health-and-medicine/human-anatomy-a… Missed the previous lesson?

The pulmonary system including the lungs, larynx, trachea, bronchi, bronchioles, alveoli and thoracic diaphragm. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/health-and-medicine/respiratory-sys… Missed the previous lesson?

Learn about diffusion, osmosis, and concentration gradients and why these are important to cells. Watch the next lesson: https://www.khanacademy.org/science/biology/membranes-and-transport/pas… Missed the previous lesson?

Parts of a cell: nucleus, ribosomes, endoplasmic reticulum, Golgi bodies, mitochondria, chloroplasts, vacuoles, and vesicles About Khan Academy: Khan Academy is a nonprofit with a mission to provide a free, world-class education for anyone, anywhere. We believe learners of all ages should have unlimited access to free educational content they can master at their own pace. We use intelligent software, deep data analytics and intuitive user interfaces to help students and teachers around the world.

How CAM Plants are able to fix carbon at night so they don't have to keep their stomata open during the day More free lessons at: http://www.khanacademy.org/video?v=xp6Zj24h8uA

C-4 Photosynthesis: How some plants avoid photorespiration More free lessons at: http://www.khanacademy.org/video?v=7ynX_F-SwNY

More detail on the Calvin Cycle and Photorespiration More free lessons at: http://www.khanacademy.org/video?v=EQvTEFCANTM

The Calvin Cycle or the light-independent (dark) reactions of photosythesis More free lessons at: http://www.khanacademy.org/video?v=slm6D2VEXYs

More detail on the light reactions and photophorylation More free lessons at: http://www.khanacademy.org/video?v=yfR36PMWegg

Details on the light-dependent reactions of photosynthesis More free lessons at: http://www.khanacademy.org/video?v=GR2GA7chA_c