water expulsion vesicle
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contractile vacuole — n a vacuole in a unicellular organism that contracts regularly to discharge fluid from the body * * * an osmoregulatory organelle of protozoa and sponges that alternately fills with water extracted from the adjacent cytoplasm and then ejects the… … Medical dictionary
reproductive system, animal — Introduction any of the organ systems by which animals reproduce. The role of reproduction is to provide for the continued existence of a species; it is the process by which living organisms duplicate themselves. Animals compete with… … Universalium
nervous system — Anat., Zool. 1. the system of nerves and nerve centers in an animal or human, including the brain, spinal cord, nerves, and ganglia. 2. a particular part of this system. Cf. autonomic nervous system, central nervous system, peripheral nervous… … Universalium
human disease — Introduction an impairment of the normal state of a human being that interrupts or modifies its vital functions. health versus disease Before human disease can be discussed, the meanings of the terms health, physical fitness, illness … Universalium
Strontium — (pronEng|ˈstrɒntiəm, ) is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when… … Wikipedia
reproductive system, human — Organ system by which humans reproduce. In females, the ovaries sit near the openings of the fallopian tubes, which carry eggs from the ovaries to the uterus. The cervix extends from the lower end of the uterus into the vagina, whose opening, as… … Universalium
Placenta — For the ancient Roman bread, see placenta (food). For the placenta of fruit, see placentation. Placenta Placenta Precursor … Wikipedia
human embryology — ▪ biology Introduction the process encompassing the period from the formation of an embryo, through the development of a fetus, to birth. The human body, like that of most animals, develops from a single cell produced by the union of… … Universalium
vacuole — vacuolar /vak yooh oh leuhr, vak yooh euh , vak yeuh leuhr/, adj. /vak yooh ohl /, n. Biol. 1. a membrane bound cavity within a cell, often containing a watery liquid or secretion. See diag. under cell. 2. a minute cavity or vesicle in organic… … Universalium
Cell nucleus — HeLa cells stained for the cell nucleus DNA with the Blue Hoechst dye. The central and rightmost cell are in interphase, thus their entire nuclei are labeled. On the left, a cell is going through mitosis and its DNA has condensed ready for… … Wikipedia
