2. in psychiatry, an unconscious defense mechanism in which unacceptable ideas, fears, and impulses are thrust out or kept out of consciousness. 3. gene r. enzyme repression interference, usually by the endproduct of a pathway, with synthesis of the enzymes of that pathway. gene repression the inhibition of gene transcription of an operon; in prokaryotes repressor binding to the operon is involved.
Hyperkalemia can result from increased potassium intake, decreased potassium excretion, or a shift of potassium from the intracellular to the extracellular space. The most common causes involve decreased excretion. Alone, excessive intake or an extracellular shift is distinctly uncommon.
What is the effect of extra-cellular potassium concentration on heart rate and conduction velocity? If the extracellular potassium concentration surrounding a myocyte increases, then the potassium gradient accross the cell membrane decreases, and therefore the resting membrane potential will become more positive. Similarly, if extracellular potassium decreases, the resting membrane potential will be more negative.