U


ultratrace element An element vital to an animal in very small amounts. 32

umbilical cord um-BIL-ik-kel KORD A ropelike structure that contains one vein and two arteries that connects a pregnant female placental mammal to unborn offspring. 216

unconditioned stimulus A stimulus that normally triggers a particular response. 815

uniramous uni-RAY-muss A single-lobed arthropod appendage. 522

unsaturated un-SAT-yur-RAY-tid (fat) A triglyceride with double bonds between some of its carbons. 45

upwelling Upward movement of nutrient-rich lower layers of a body of water. 883

uracil YUR-eh-sil One of two pyrimidine bases in RNA. 51

urea u-REE-ah A nitrogenous waste derived from ammonia. 776

ureter YEW-re-ter A muscular tube that transports urine from the kidney to the bladder. 780

urethra u-RETH-rah Tube that transports urine from the bladder out of the body. 197, 780

uric acid YOUR-ik AS-id A nitrogenous waste derived from ammonia. 776

urinary bladder YOUR-en-air-ee BLAD-er A muscular sac where urine collects. 780

uterus U-ter-us The muscular, saclike organ in a female placental mammal where the embryo and fetus develop. 197

utricle U-trah-kel A pouch in the vestibule of the inner ear filled with a jellylike fluid and lined with hair cells that contain calcium carbonate granules that move in response to changes in velocity, firing action potentials. 655

Return to Glossary

feedback form | permissions | international | locate your campus rep | request a review copy

digital solutions | publish with us | customer service | mhhe home


Copyright ©2001 The McGraw-Hill Companies.
Any use is subject to the Terms of Use and Privacy Policy.
McGraw-Hill Higher Education is one of the many fine businesses of the The McGraw-Hill Companies.