overdrive suppression


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suppression

 [sŭ-presh´un]
the act of holding back or checking.
1. the stopping or inhibition of something, such as a secretion, excretion, normal discharge, or other function.
2. in psychiatry, conscious inhibition of an unacceptable impulse or idea as contrasted with repression, which is unconscious.
3. in genetics, a second mutation occurring at a site different from the first mutation site and able to mask or suppress the phenotypic expression of the first mutation; the organism appears to be reverted but is in fact doubly mutant.
4. inhibition of the erythrocytic stage of Plasmodium to prevent clinical attacks of malaria; used for prophylaxis.
5. cortical inhibition of perception of objects in all or part of the visual field of one eye during binocular vision.
bone marrow suppression reduction of the cell-forming functions of bone marrow, such as by a drug or because of replacement of the marrow by a disease process. Called also myelophthisis and myelosuppression.
labor suppression in the nursing interventions classification, a nursing intervention defined as controlling uterine contractions prior to 37 weeks of gestation to prevent preterm birth. See also labor.
lactation suppression in the nursing interventions classification, a nursing intervention defined as facilitating the cessation of lactation and minimizing breast engorgement after childbirth.
overdrive suppression the suppression of intrinsic cellular automaticity by a rapid outside stimulus. In cardiology this refers to the inhibitory effect of a faster pacemaker on a slower pacemaker. The faster rate causes an accumulation of intracellular sodium, stimulating the sodium-potassium pump, which hyperpolarizes the cell so that it takes longer to reach threshold potential. This phenomenon is present in healthy His-Purkinje cells but decreases with a decrease in membrane potential and loss of fast sodium channels.

overdrive suppression

[-drīv]
Etymology: AS, ofer + drifan, to drive
the inhibitory effect of a faster cardiac pacemaker on a slower one.

overdrive suppression

inhibitory effect of a fast cardiac pacemaker on a slow pacemaker.