An action potential is a very rapid change in membrane potential that occurs when a nerve cell membrane is stimulated. Specifically, the membrane potential goes from the resting potential (typically -70 mV) to some positive value (typically about +30 mV) in a very short period of time (just a few milliseconds).eurons can respond to stimuli and conduct impulses because a membrane potential is established across the cell membrane. In other words, there is an unequal distribution of ions (charged atoms) on the two sides of a nerve cell membrane.
Aardvarks are small pig-like mammals that are found inhabiting a wide range of different habitats throughout Africa, south of the Sahara. They are mostly solitary and spend their days sleeping in underground burrows to protect them from the heat of the African sun, emerging in the cooler evening to search for food.
The main predators of the walrus are polar bears, killer whales, and humans. Humans have hunted the walrus since the days of the Vikings and early Native Americans. It is the Atlantic walrus that was the hardest hit by humans because the population centers of the world were in their area (northern Europe) for the longest time.