Resting State: The neuron is at rest, with a negative charge inside and a positive charge outside. The voltage-gated ion channels are closed.
Depolarization: The neuron is stimulated, causing the membrane potential to become less negative. If the depolarization reaches the threshold, voltage-gated sodium channels open, allowing an influx of sodiumions.
Propagation: The depolarization triggers adjacent regions of the axon to reach threshold and generate their own action potentials, leading to the propagation of the signal along the axon.
Repolarization: After reaching its peak, the membrane potential starts to become more negative again as voltage-gated potassium channels open, allowing an efflux of potassiumions.
Hyperpolarization: The membrane potential briefly becomes more negative than the resting state due to the prolonged efflux of potassiumions, before returning to the resting state.
Factors Affecting Action Potential
Several factors can affect the generation and propagation of action potentials, including temperature, myelination of the axon, and the diameter of the axon.
When studying action potentials, it's important to grasp the underlying mechanisms, including the roles of ion channels and the sequence of events during depolarization, propagation, and repolarization. Practice drawing and labeling the changes in membrane potential during an action potential. Additionally, explore clinical applications and research related to action potentials to appreciate their significance in various contexts.
Energy - A. Energy is involved in all physical and chemical processes. It is conserved, and can be transformed from one form to another and into work. At the atomic and nuclear levels energy is not continuous but exists in discrete amounts. Energy and mass are related through Einstein's equation E=mc 2 . B. The properties of atomic nuclei are responsible for energy-related phenomena such as radioactivity, fission and fusion. C. Changes in entropy and energy that accompany chemical reactions influence reaction paths. Chemical reactions result in the release or absorption of energy. D. The theory of electromagnetism explains that electricity and magnetism are closely related. Electric charges are the source of electric fields. Moving charges generate magnetic fields. E. Waves are the propagation of a disturbance. They transport energy and momentum but do not transport matter.
Relate temperature to the average molecular kinetic energy.