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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.
In the physiology of the kidney, tubuloglomerular feedback (TGF) is a feedback system inside the kidneys. Within each nephron , information from the renal tubules (a downstream area of the tubular fluid ) is signaled to the glomerulus (an upstream area).
Paracrine signaling between neighboring cells creates this positive feedback loop. Thus, the constitutive transcription of upregulated proteins form ideal environments for tumors to arise. [ 12 ] Effectively, multiple bindings of ligands to the RTK receptors overstimulates the Ras-Raf-MAPK pathway, which overexpresses the mitogenic and invasive ...
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 .
This bistability is most obvious in the transition between the follicular and luteal phases, and arises from interactions between positive and negative feedback loops involving GnRH, LH, FSH, estrogen, and progesterone. The kisspeptin system creates a switch-like mechanism driving the transition from negative to positive feedback.
Thyrotropic feedback control on a more detailed and quantitative level. [3] Thyroid homeostasis results from a multi-loop feedback system that is found in virtually all higher vertebrates. Proper function of thyrotropic feedback control is indispensable for growth, differentiation, reproduction and intelligence.
The positive feedback of the rising phase slows and comes to a halt as the sodium ion channels become maximally open. At the peak of the action potential, the sodium permeability is maximized and the membrane voltage V m is nearly equal to the sodium equilibrium voltage E Na .
Schematic of the HPA axis (CRH, corticotropin-releasing hormone; ACTH, adrenocorticotropic hormone) Hypothalamus, pituitary gland, and adrenal cortex The hypothalamic–pituitary–adrenal axis (HPA axis or HTPA axis) is a complex set of direct influences and feedback interactions among three components: the hypothalamus (a part of the brain located below the thalamus), the pituitary gland (a ...