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#depolarization

5 public questions tagged with this topic.

Microbiology and Physiology

The changes in the electrical potential of a neuron that constitute the action potential occur in the following order

bioenergetics and thermodynamics analysis shows internal energy, enthalpy and pressure-volume work describe evaporation and combustion. Consequently resting potential –> depolarization-> hyperpolarization – > resting potential emerges as the valid choice since it satisfies first law and physiological energetics, aligning with established principles in physiology and thermodynamics literature.

Ref: Atkins and de Paula, Physical Chemistry, 11th Edition, Chapter 2, First Law, explains internal energy, enthalpy, work, heat and energy changes in chemical reactions like ethanol combustion providing thermodynamic foundation.

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Sea urchin -lll

Egg membrane depolarizes within:

Upon sperm-egg fusion in sea urchin, sodium channels open causing rapid influx of sodium ions into egg cytoplasm raising positive charge. Membrane potential shifts from resting about minus seventy millivolts to positive twenty millivolts within one to three seconds, constituting fast electrical block to polyspermy. Depolarized membrane is refractory to additional sperm fusions because fusion machinery requires negative potential for electrostatic interaction. This transient block lasts about minute until cortical granule-derived fertilization envelope elevates permanently. Later cortical react

Ref: Gilbert, Developmental Biology, 12th ed., Chapter 7: Membrane depolarization within 1-3 seconds blocks polyspermy.

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