Signals (biology)

Bioelectromagnetism (sometimes equated with bioelectricity) refers to the static voltage of biological cells and to the electric currents that flow in living tissues, such as nerves and muscles, as a result of action potentials. Bioelectromagnetism - Description. Biological cells use bioelectricity to store metabolic energy, to do work or trigger internal changes, and to signal one another. Bioelectromagnetism is the electric current produced by action potentials along with the magnetic fields they g ...

Including:

• Bioelectromagnetism - Description
• Bioelectromagnetism - Volume Conductors
• Bioelectromagnetism - Quotes

Read more here: » Bioelectromagnetism: Encyclopedia - Bioelectromagnetism

An action potential is a wave of electrical discharge that travels along the membrane of a cell. Action potentials are used by the body to communicate fast internal messages between its tissues making them an essential feature of animal life at the microscopic level. They can be created by many types of body cells, but are used most extensively by the nervous system to send messages between nerve cells and from nerve ...

Including:

• Action potential - Overview
• Action potential - Underlying mechanism
• Action potential - Resting membrane potential
• Action potential - Action potential phases
• Action potential - Threshold and initiation
• Action potential - Circuit model
• Action potential - Propagation
• Action potential - Speed of propagation
• Action potential - Saltatory conduction
• Action potential - Refractory period
• Action potential - Why an action potential?

Read more here: » Action potential: Encyclopedia - Action potential

Action potentials are triggered when an initial depolarization reaches threshold. This threshold potential varies, but generally is about 15 millivolts above the cell's resting membrane potential, occurring when the inward sodium current exceeds the outward potassium current. The net influx of positive charges carried by sodium ions depolarizes the membrane potential, leading to the further opening of voltage-gated sodium channels. These channels support greater inward current causing further depolarization, creating a positive-feedback cycle th ...

See also:

Action potential, Action potential - Overview, Action potential - Underlying mechanism, Action potential - Resting membrane potential, Action potential - Action potential phases, Action potential - Threshold and initiation, Action potential - Circuit model, Action potential - Propagation, Action potential - Speed of propagation, Action potential - Saltatory conduction, Action potential - Refractory period, Action potential - Why an action potential?

Read more here: » Action potential: Encyclopedia II - Action potential - Threshold and initiation

Biological cells use bioelectricity to store metabolic energy, to do work or trigger internal changes, and to signal one another. Bioelectromagnetism is the electric current produced by action potentials along with the magnetic fields they generate through the phenomenon of electromagnetic induction. Bioelectromagnetism is studied primarily through the techniques of electrophysiology. In the late eighteenth century, the Italian physician and physicist, Luigi Galvani, first recorded the phenomenon while dissecting a frog at a table whe ...

See also:

Bioelectromagnetism, Bioelectromagnetism - Description, Bioelectromagnetism - Volume Conductors, Bioelectromagnetism - Quotes

Read more here: » Bioelectromagnetism: Encyclopedia II - Bioelectromagnetism - Description

In standard electrical engineering guidelines, the 3 fundamental units of Resistance, Voltage & Current are seen as inhomogeneous values(ie: discrete). However, in Bioelectromagnetism these 3 fundamental units are treated as a single homogeneous object, a method of working with this rule is a visual model called a Volume conductor.... ...

See also:

Bioelectromagnetism, Bioelectromagnetism - Description, Bioelectromagnetism - Volume Conductors, Bioelectromagnetism - Quotes

Read more here: » Bioelectromagnetism: Encyclopedia II - Bioelectromagnetism - Volume Conductors

Although the passive transmission of action potentials across myelinated segments would suggest that action potentials propagate in either direction, most action potentials travel unidirectionally because the node behind the propagating action potential is refractory. Where membrane has undergone an action potential, a refractory period follows. This period arises primarily because of the voltage-dependent inactivation of sodium channels, as described by Hodgkin and Huxley in 1952. In addition to the voltage-dependent opening o ...

See also:

Action potential, Action potential - Overview, Action potential - Underlying mechanism, Action potential - Resting membrane potential, Action potential - Action potential phases, Action potential - Threshold and initiation, Action potential - Circuit model, Action potential - Propagation, Action potential - Speed of propagation, Action potential - Saltatory conduction, Action potential - Refractory period, Action potential - Why an action potential?

Read more here: » Action potential: Encyclopedia II - Action potential - Refractory period

Action potential - Resting membrane potential. The membrane voltage changes that take place during an action potential result from changes in the permeability of the membrane to specific ions (particularly sodium and potassium), the internal and external concentrations of which cells maintain in an imbalance. This imbalance makes possible not only action potentials but also the resting cell potential arises through the work of pumps (eg, the sodium-potassium exchanger) as well as ion channels (eg, the potassium l ...

See also:

Action potential, Action potential - Overview, Action potential - Underlying mechanism, Action potential - Resting membrane potential, Action potential - Action potential phases, Action potential - Threshold and initiation, Action potential - Circuit model, Action potential - Propagation, Action potential - Speed of propagation, Action potential - Saltatory conduction, Action potential - Refractory period, Action potential - Why an action potential?

Read more here: » Action potential: Encyclopedia II - Action potential - Underlying mechanism

In unmyelinated axons, action potentials propagate as an interaction between passively spreading membrane depolarization and voltage-gated sodium channels. When a single patch of cell membrane is depolarized sufficiently to open its voltage-gated sodium channels, sodium ions enter the cell by facilitated diffusion. Once inside, positively-charged sodium ions "nudge" adjacent ions down the axon by electrostatic repulsion (analogous to the principal behind Newton's cradle) and attract negative ions away from the adjacent membrane. As a result, ...

See also:

Action potential, Action potential - Overview, Action potential - Underlying mechanism, Action potential - Resting membrane potential, Action potential - Action potential phases, Action potential - Threshold and initiation, Action potential - Circuit model, Action potential - Propagation, Action potential - Speed of propagation, Action potential - Saltatory conduction, Action potential - Refractory period, Action potential - Why an action potential?

Read more here: » Action potential: Encyclopedia II - Action potential - Propagation

An electrical voltage, or potential, always exists between the inside and outside of a cell. The voltage of an inactive cell stays at a negative value (inside relative to outside the cell) and varies within a small range. When the membrane potential of an excitable cell is depolarized beyond a threshold, the cell will undergo (or "fire") an action potential (see Threshold and initiation). At its most basic, an action potential is a very rapid swing in the polarity of the membrane potential from negative to positive and back, th ...

See also:

Action potential, Action potential - Overview, Action potential - Underlying mechanism, Action potential - Resting membrane potential, Action potential - Action potential phases, Action potential - Threshold and initiation, Action potential - Circuit model, Action potential - Propagation, Action potential - Speed of propagation, Action potential - Saltatory conduction, Action potential - Refractory period, Action potential - Why an action potential?

Read more here: » Action potential: Encyclopedia II - Action potential - Overview