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An alpha subunit forms the core of the channel and is functional on its own. When the alpha subunit protein is expressed by a cell, it is able to form a pore in the cell membrane that conducts Na + in a voltage-dependent way, even if beta subunits or other known modulating proteins are not expressed. When accessory proteins assemble with α ...
Several types of cells support an action potential, such as plant cells, muscle cells, and the specialized cells of the heart (in which occurs the cardiac action potential). However, the main excitable cell is the neuron, which also has the simplest mechanism for the action potential. [citation needed]
The action potential passes along the cell membrane causing the cell to contract, therefore the activity of the sinoatrial node results in a resting heart rate of roughly 60–100 beats per minute. All cardiac muscle cells are electrically linked to one another, by intercalated discs which allow the action potential to pass from one cell to the ...
Cells may draw on the energy they store in the resting potential to drive action potentials or other forms of excitation. These changes in the membrane potential enable communication with other cells (as with action potentials) or initiate changes inside the cell, which happens in an egg when it is fertilized by a sperm.
Neutrophils extravasate from blood vessels to the site of tissue injury or infection during the innate immune response.. In immunology, leukocyte extravasation (also commonly known as leukocyte adhesion cascade or diapedesis – the passage of cells through the intact vessel wall) is the movement of leukocytes (white blood cells) out of the circulatory system (extravasation) and towards the ...
In physiology, [B: 2] a refractory period is a period of time during which an organ or cell is incapable of repeating a particular action, or (more precisely) the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following an excitation. It most commonly refers to ...
Action potential in a neuron, showing depolarization, in which the cell's internal charge becomes less negative (more positive), and repolarization, where the internal charge returns to a more negative value. Most cells in higher organisms maintain an internal environment that is negatively charged relative to the cell's exterior.
Electrotonic potentials represent changes to the neuron's membrane potential that do not lead to the generation of new current by action potentials. [1] However, all action potentials are begun by electrotonic potentials depolarizing the membrane above the threshold potential which converts the electrotonic potential into an action potential. [2]