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Khan Academy on a Stick

Health and medicine

Neural cells and neurotransmitters

Get an overview of the structure and function of neurons, and learn about the many other important cells needed to help our nervous system function optimally! By Matt Jensen.

Neuron membrane potentials

Learn the causes and functions of neuron membrane potentials, including resting, graded, and action potentials.

Sensory perception

Learn about how we perceive our various senses, including the theories, laws, and organizational principles that underly our ability to make sense of the world around us.

  • The structure of the eye

    In this video, I review the structure of the eye. By Ronald Sahyouni.

  • Visual sensory information

    In this video, I explore our sense of vision. By Ronald Sahyouni.

  • The phototransduction cascade

    This explains phototransduction cascade which is critical to our sense of vision. By Ronald Sahyouni.

  • Photoreceptors (rods vs cones)

    In this video, I explore the similarities and differences between rods and cones. By Ronald Sahyouni.

  • Photoreceptor distribution in the fovea

    In this video, I explore how photoreceptors (rods and cones) are distributed in the fovea. By Ronald Sahyouni.

  • Visual field processing

    In this video, I review how we process our visual field, and how information from the right and left visual field is broken down and sent to the brain. By Ronald Sahyouni.

  • Feature detection and parallel processing

    In this video, I review our ability to break down an image into its component "features" such as color, form, and motion. This is known as feature detection, and since the detection of various features happens simultaneously, or in parallel, it is referred to as parallel processing.  By Ronald Sahyouni.

Sight (vision)

Photons are hitting your eye as you read this! Learn about our sense of sight, including the cells responsible for converting light into a neural impulse, the structure of the eye, and how we break down images to make sense of them.

Sound (Audition)

Learn about how we hear, including the structure of the outer, middle, and inner ear, as well as the basics of auditory processing & cochlear implants.

  • Somatosensation

    Explore our ability to sense the environment through our body.  By Ron.

  • Sensory adaptation and amplification

    Sensory adaptation and amplification are discussed in this video to differentiate the two.  By Ronald Sahyouni.

  • Somatosensory homunculus

    In this video, I review the somatosensory homunculus, which is basically a "topological" representation of the body in the brain.  By Ronald Sahyouni.

  • Proprioception and kinesthesia

    The differences between propioception (sense of body position) and kinesthesia (sense of body movement) are discussed.  By Ronald Sahyouni.

  • Pain and temperature

    Explore our senses of pain & temperature.  By Ron.

Somatosensation

We perceive the environment through our bodily senses, including our sensation of pain, temperature, pressure, balance, and movement. Discover how our body gathers this information and processes it so that we can make sense of the world.

Taste (gustation) and smell (olfaction)

Learn about our senses of smell (olfaction) and taste (gustation), including the anatomy and underlying molecular basis behind these important senses.