Glossary

Author: Glossary

  • Periodic health examination

    A health screening examination performed on a scheduled or routine basis. The appropriate features of this examination depend on the patient’s age, gender, and sometimes health history, family history, or employment status. Adult women, for example, should have periodic examinations, including Pap smears and professional breast examinations, whereas professional pilots and truckers are screened periodically…

  • Periodic catatonia

    An inherited form of schizophrenia characterized by psychomotor disturbances, including grimacing, stereotyped body movements, and hyperkinetic movements alternating with mutism, staring, and body posturing. Susceptibility to this condition has been linked to genes on chromosome 15.  

  • Periodic abstinence

    A method of birth control in which a couple tries to avoid pregnancy by refraining from sexual intercourse during certain times within the menstrual cycle.  

  • Silent period

    The time in the course of a disease in which the signs and symptoms are so mild as to be difficult to detect.  

  • Relative refractory period

    The period after activation of a nerve or muscle, during recovery, when it can be excited only by a stronger-than-normal stimulus. The brief period during repolarization of a neuron or muscle fiber when excitability is depressed. If stimulated, the cell may respond, but a stronger than usual stimulus is required.  

  • Presphygmic period

    The short period in systole beginning with closing of the atrioventricular valves and ending with opening of the valves connecting the right and left ventricles to the pulmonary artery and aorta, respectively.  

  • Postsphygmic period

    The short period in diastole when the ventricles are relaxed and no blood is entering. This lasts until the atrioventricular valves open.  

  • Isoelectric period

    In an occurrence that normally produces an electric force, such as a muscle contraction, the time or point when no electrical energy is produced.  

  • Effective refractory period

    In electrocardiography, the interval during which a second action potential cannot occur in an excitable fiber unless the stimulus is much stronger than usual; the membrane is still in the repolarization phase of the previous action potential.  

  • Absolute refractory period

    Following contraction of a muscle fiber or transmission of a nerve impulse by a neuron, the period in which a stimulus, no matter how strong, will not elicit a response. The brief period during depolarization of a neuron or muscle fiber when the cell does not respond to any stimulus, no matter how strong.