Search results
Results From The WOW.Com Content Network
Positive feedback is used in digital electronics to force voltages away from intermediate voltages into '0' and '1' states. On the other hand, thermal runaway is a type of positive feedback that can destroy semiconductor junctions. Positive feedback in chemical reactions can increase the rate of reactions, and in some cases can lead to explosions.
Positive feedback loops, on their own or in combination with negative feedback are a common feature of oscillating biological systems. [2] Examples
The Hodgkin cycle represents a positive feedback loop in which an initial membrane depolarization leads to uncontrolled deflection of the membrane potential to near V Na. The initial depolarization must reach or surpass a certain threshold in order to activate voltage-gated Na + channels .
Na + channels both open and close more quickly than K + channels, producing an influx of positive charge (Na +) toward the beginning of the action potential and an efflux (K +) toward the end. Ligand-gated sodium channels, on the other hand, create the change in the membrane potential in the first place, in response to the binding of a ligand ...
Positive feedback occurs when the fed-back signal is in phase with the input signal. Under certain gain conditions, positive feedback reinforces the input signal to the point where the output of the device oscillates between its maximum and minimum possible states. Positive feedback may also introduce hysteresis into a circuit. This can cause ...
Ovulation induction is usually initially performed by giving an antiestrogen such as clomifene citrate or letrozole in order to decrease negative feedback on the pituitary gland, resulting in an increase in FSH with the aim of increasing folliculogenesis. It is the main initial medical treatment for anovulation.
Hemostasis can be achieved in various other ways if the body cannot do it naturally (or needs help) during surgery or medical treatment. When the body is under shock and stress, hemostasis is harder to achieve. Though natural hemostasis is most desired, having other means of achieving this is vital for survival in many emergency settings.
The switch to autogenic excitation is a form of positive feedback. [10] The ascending or afferent pathways to the cerebellum are the dorsal and ventral spinocerebellar tracts. They are involved in the cerebellar regulation of movement. [citation needed]