Nerve impulse, Biology


  1. It is an electro chemical phenomenon manifested through ionic movement across cell membrane.
  2. It was discovered by A. L. Hodykin & A. F. Huxley (1939).
  3. Impulse is a change in resting membrane potential of the cell towards positive side, also called as action potential or spike potential.
  4. All cells bear positive charge outside (due to Na+) and negativity inside thus membrane remain in polarised state.
  5. This potential across the membrane can be measured by putting electrodes inside & outside connected to a galvanometer or potentiometer or a voltameter.
  6. When the cell is at normal resting state, the potential in animal cell ranges from - 60 mv to - 90 mv, this is called resting potential (nerve cell has about - 70 mv)
  7. Any ext. stimulus reaching the membrane causes change in its permeability and Na+ starts rushing inside which results in the rise of potential towards positive side. This process of charge in potential (action potential) is called as depolarisation.
  8. To bring the condition back to normal in nerve cell it is followed by exit of K+  out of the cell which results in resumption of the resting potential known as repolarisation.
  9. Since the rate of exit of K+ is very slow while rate of entry of Na+ is very fast, this result in rise & stay of action potential for some time.
Posted Date: 10/3/2012 2:19:51 AM | Location : United States

Related Discussions:- Nerve impulse, Assignment Help, Ask Question on Nerve impulse, Get Answer, Expert's Help, Nerve impulse Discussions

Write discussion on Nerve impulse
Your posts are moderated
Related Questions
phyla of animal like protists that have free living members

Excretion in Animals Excretion is concerned along with the removal of metabolic wastes that arise as a result of oxidation of energy rich compounds and metabolism of proteins

true or false. the law of entropy says that all energy is ultimately derived from the sun

How we can measure perimplant PD Perimplant PD should be measured routinely during maintenance appointment with a less probing force (0.2 to 0.3 N) as the tissue is more sensit

Exocytosis in a skeletal muscle?   A.  During exocytosis in a skeletal muscle, there will be release of calcium ions from intracellular vesicles in the sarcoplasmic reticulum i

Explain Potential Health Benefits of Dietary Fibre? A number of experimental studies in animal models, as well as, epidemiological studies have established protective role of d

Explain the summary of morbidity  in CAD? i) The prevalence of CAD among immigrant Indians is about three-fold higher than in comparable indigenous populations; ii) CAD tends t

Define Solvent Chemical Potentials from Phase Equilibria? Previously explained how we can evaluate the activity coefficient γ m,B of a nonelectrolyte solute of a binary soluti

Q. What is the difference between facilitated and simple diffusion? Facilitated by which kind of molecule does the term "facilitated" mean? Simple diffusion is the direct passa

Homozygous and Weterozygous In an individual two identical alleles may exist [or a given character and, hence, the individual is referred to as Homozygous (e.g. AA and aa). If