{unipolar neuron}{}{One of the three categories of neurons consisting of a nerve cell body with a single axon projecting from it; also called a pseudounipolar neuron.}

{unsaturated}{}{Carbon chain of a fatty acid that possesses one or more double or triple bonds.}

{uracil}{}{One of four nucleotides found in RNA; abbreviated "U."}

{ureter}{}{Muscular tube that carries urine from the kidney to the urinary bladder.}

{urethra}{}{Tube leading from the urinary bladder to the outside of body.}

{urinary bladder}{}{Muscular storage compartment for urine prior to urination.}

{urine}{}{Wastes and excess water removed from the blood and excreted by the kidneys into the ureters, to the urinary bladder, and out of the body through the urethra.}

{uterus}{}{Hollow, muscular organ within female pelvis in which fetus develops.}

{utricle}{}{Part of the membranous labyrinth; contains sensory structure, the macula, that detects static equilibrium.}