Latency Period


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Latency Period

 

(1) In physiology, the time from the moment of stimulation of an organism, organ, tissue, or cell until the manifestation of a responsive reaction.

The duration of the latency period depends on the level of phylogenetic development, individual development, and functional state of the body and on the complexity of the reaction and the speed of the processes in its peripheral and central links. Thus, the latency period of a given reflex consists of the time it takes to transform the energy of the external stimulus in the receptor, the time necessary to conduct the excitation along the nerve fibers, the duration of the synaptic lags, and the time required to trigger the effectors.

The latency period of psychological reactions characterizes the level of wakefulness and the states of attentiveness and tension. Determination of the magnitude of the latency period is of great importance in physiology, medicine (for studying the functions of the healthy and the diseased body), and experimental psychology.

(2) The latency period of pregnancy is a temporary lag in the development of the fertilized ovum in certain mammals; during the late blastula stage, the embryo lives in the womb for several months without attaching to the uterine mucosa. Fertilization of the sable, marten, ermine, badger, and roe deer occurs during the summer-fall period, but accelerated development of the ovum does not begin until the end of winter; hence, gestation in those animals goes on for nine months or more.

(3) In medicine, incubation period; the initial, latent period of a disease, without external manifestation.

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References in periodicals archive ?
Our results showing the highest risk for exposure to phenoxyacetic acids and chlorophenols with a rather short latency period (Hardell et al.
We know from FDA's own research that the latency period for harm from silicone breast implants is seven to ten years.
However Australia's mining union, the CFMEU told local media on Wednesday the return of the disease, which has a long latency period, caused by long term exposure to coal dust in areas with poor ventilation, has sent shockwaves through the industry.
Dust from asbestos can trigger the deadly lung disease, mesothelioma, but the long latency period means many victims are unaware of asbestos exposure until decades later.
Latency periods vary by different type of cancer of interest, with some cancers having a typical latency period of 15 to 20 years or longer, while some cancers typically have latency periods that are considerably shorter.
Additionally, in PSReA the latency period is about 1-2 weeks, shorter than ARF and cardiac/kidney involvement is also rare.
As this disease has such a long latency period the fear is it could be transmitted via infected beef and then years go by before anyone knows a population was affected.
Asbestos has an average 30 to 40-years latency period between exposure to asbestos fibres and the onset of disease.
Assured points out asbestos illnesses have a long latency period that could reach beyond 40 years.
Fourth, the standard divorces itself from physical presences because the latency period is defined by reference to economic contacts, not physical contacts.
Chronic cadmium poisoning has a latency period of 15 to 20 years.