Category: L

  • Lethal factor

    In genetics, a genetic factor that brings about the early death of the organism. A gene or an abnormality in genetic composition that causes death of a zygote or of an individual before the reproductive age.  

  • Letdown

    A tingling sensation in the breasts when milk is forced out shortly after the baby begins to suckle. Sensation in the breasts of nursing women as the milk flows into the ducts of the breast, as when the infant begins to suck or when the mother prepares to nurse; also called milk-ejection reflex.  

  • Lessons and units

    Subcategories of a curriculum that center on specific themes or a central purpose. Each lesson or unit has a set of objectives that center on the theme of the lesson or unit.  

  • Lesson plan

    The functional culmination of all curriculum planning and development. It describes what will happen to the learner and how it shall take place on a day-to-day basis.  

  • Lesion, neural

    Injury in a specific area of the brain or nervous system.  

  • Lesbianism

    Lesbianism

    Homosexuality in women. Sexual attraction in one woman for another. Sexual attraction and relations between women. As with male homosexuality, lesbianism is not a lifestyle choice but an inborn predisposition. Homosexuality is not considered a disorder. The condition in which a woman is sexually attracted to, or engages in sexual behavior with, another woman. Treatment…

  • Leptospirosis

    A rare bone disease whose causative agent is Leptospira, a genus of spirochetes. A genus of bacteria excreted continuously in the urine of rats and many domestic animals. It can infect humans, causing leptospirosis or Weil’s disease. An infectious disease caused by the spirochaete Leptospira, transmitted to humans from rat urine, causing jaundice and kidney…

  • Leptosome

    A body type identified by Kretschmer whose temperament was supposed to be schizothymic pyknic.  

  • Leptonema

    A stage in meiosis immediately preceding synapsis in which the chromosomes appear to be single, threadlike structures. The early stage of prophase in meiosis. At this stage the chromatin coils into visible filaments.  

  • Lentiviruses

    Viruses that cause disease very slowly. HIV is thought to be this type of virus. A group of retroviruses that cause slowly developing diseases as a result of the gradual killing of lymphoid cells. Human immunodeficiency virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS), is included in this group of viruses.