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In this interrupted case study, students meet a pair of fictional newlyweds on their way to Australia for their honeymoon. Initially eager to enjoy the sun, sand, and sights, Tanya and Julien Brahim end up more intimately acquainted with the local wildlife than they had planned. Tanya is bitten by a venomous arachnid and Julien has a run-in with a dangerous cnidarian. This case study was created to help students solidify their knowledge about cardiac myocytes, particularly ion movements associated with action potential generation in autorhythmic and contractile cells. As students work through the case, they will complete fill-in-the-blank paragraphs describing the heart, diagram membrane potentials and ion movements, and compare and contrast action potentials from different cell types. Written for a course in human physiology, the case requires some prior knowledge of membrane potentials, equilibrium potentials, ion gradients, neuronal action potentials, and skeletal muscle action potentials. An optional pre-case assignment (included in the teaching notes) can be used to make sure that students are familiar with the necessary concepts.

In this video Paul Andersen explains how the electrochemical gradient is a combination of the chemical and electrical gradient of ions. As ions move across a membrane the potential change creates a hidden force that isn't always apparent.

What do you and a sack of batteries have in common? Today, Hank explains. -- Table of Contents: Ion Channels Regulate Electrochemistry to Create Action Potential 4:51 Resting State 3:22 Depolarization 6:09 Repolarization 7:35 Hyperpolarization 8:00

In this video Paul Andersen details the action potential in neurons. The resting potential of a neuron (-70mV) is maintained through differences in concentration and permeability of Na, K, and Cl ions. A graded potential is created as neurotransmitters from adjacent cells that are either excitatory or inhibitory. If the neuron reaches the threshold of -55mV an opening of voltage-gated sodium channels triggers an action potential

Dr. Richard Lifton, along with student volunteers, uses an aquarium and salt to illustrate the amount of work the kidney performs each day to maintain proper levels of ions in the body.

Movement of ions in and out of cells is crucial to maintaining homeostasis within the body and ensuring that biological functions run properly. The natural movement of molecules due to collisions is called diffusion. Several factors affect diffusion rate: concentration, surface area, and molecular pumps. This activity demonstrates diffusion, osmosis, and active transport through 12 interactive models. Start by following the path of a molecule of dye in water, create concentration gradients on either side of a cell membrane and watch the movement of substances in and out of a cell, and monitor the movement of oxygen into red blood cells with and without hemoglobin.

Awesome interactive player

In their May 2015 Scientific American article "Cellular Small Talk," Dale W. Laird, Paul D. Lampe and Ross G. Johnson report on recent discoveries showing that the disruption of cellular structures called gap junctions can cause various diseases.

Two thirds of the population believes a myth that has been propagated for over a century: that we use only 10% of our brains. Hardly! Our neuron-dense brains have evolved to use the least amount of energy while carrying the most information possible -- a feat that requires the entire brain.