Category: R

  • Ricinoleic acid

    12-hydroxy-9-octadecanoic acid; an unsaturated hydroxy acid comprising about 80% of fatty acids in the glycerides of castor oil. It has a strong laxative action.  

  • Ricinine

    A poisonous alkaloid present in the leaves and seeds of the castor bean plant, Ricinus communis.  

  • Ricin

    A white, amorphous, highly toxic protein present in the seed of the castor bean, Ricinus communis. It has been used as a biological weapon.  

  • Ribonucleotide

    A nucleotide in which the sugar ribose is combined with the purine or pyrimidine base.  

  • Riboflavin rib

    A water-soluble vitamin of the B complex group. It is an orange-yellow crystalline powder. Symptoms of riboflavin deficiency are photophobia, cheilosis, glossitis, and seborrheic dermatitis, especially of the face and scalp.  

  • Rhytidosis

    Wrinkling of the cornea, which occurs when tension in the eyeball is greatly diminished, particularly after the escape of aqueous or vitreous humor; usually a sign of impending death. A wrinkling, notably of the cornea, often seen as a sign of impending death.  

  • Rhythm method of birth control

    A method preventing pregnancy that uses abstinence from sexual relations around the time of ovulation.  

  • Rhotacism

    Overuse or improper utterance of “r” sounds.  

  • Rhopheocytosis

    The mechanism by which ferritin is transferred from macrophages in the bone marrow to normoblasts.  

  • Rhomboideus

    One of two muscles beneath the trapezius muscle.