Lecture

The action potential

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Description

This lecture covers the Hodgkin and Huxley model for ion conductance, focusing on the ionic basis of the action potential. It explains the activation and inactivation mechanisms of potassium and sodium channels, as well as the initiation and propagation of the action potential.

In MOOC

Cellular Mechanisms of Brain Function

The function of the brain is to govern behavior, and the aim of this course is to causally link biophysical mechanisms with simple behaviors studied in mice. The brain processes information through the concerted activity of many neurons, which communicate with each other through synapses organised in highly dynamic networks. The first goal of the course is to gain a detailed understanding of the structure and function of the fundamental building blocks of the mammalian brain, its synapses and neurons (Weeks

Official source

Quiz

Ontological neighbourhood

Biology

Cell biology: Neurotransmission

Related concepts (30)

Action potential

An action potential occurs when the membrane potential of a specific cell rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and in some plant cells. Certain endocrine cells such as pancreatic beta cells, and certain cells of the anterior pituitary gland are also excitable cells.

Membrane potential

Membrane potential (also transmembrane potential or membrane voltage) is the difference in electric potential between the interior and the exterior of a biological cell. That is, there is a difference in the energy required for electric charges to move from the internal to exterior cellular environments and vice versa, as long as there is no acquisition of kinetic energy or the production of radiation. The concentration gradients of the charges directly determine this energy requirement.

Threshold potential

In electrophysiology, the threshold potential is the critical level to which a membrane potential must be depolarized to initiate an action potential. In neuroscience, threshold potentials are necessary to regulate and propagate signaling in both the central nervous system (CNS) and the peripheral nervous system (PNS). Most often, the threshold potential is a membrane potential value between –50 and –55 mV, but can vary based upon several factors.

Postsynaptic potential

Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse. Postsynaptic potentials are graded potentials, and should not be confused with action potentials although their function is to initiate or inhibit action potentials. They are caused by the presynaptic neuron releasing neurotransmitters from the terminal bouton at the end of an axon into the synaptic cleft. The neurotransmitters bind to receptors on the postsynaptic terminal, which may be a neuron or a muscle cell in the case of a neuromuscular junction.

Ion channel

Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. Their functions include establishing a resting membrane potential, shaping action potentials and other electrical signals by gating the flow of ions across the cell membrane, controlling the flow of ions across secretory and epithelial cells, and regulating cell volume. Ion channels are present in the membranes of all cells. Ion channels are one of the two classes of ionophoric proteins, the other being ion transporters.

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Related concepts (30)

Action potential

Membrane potential

Threshold potential

Postsynaptic potential

Ion channel