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Archives: Dictionary

Darwin’s tubercle

A congenital ear condition which often presents as a thickening on the helix at the junction of the upper and middle thirds. The feature is present in approximately 10.4% of the population. This acuminate nodule represents the point of the mammalian ear....

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Death rate

1. The number of deaths in the population divided by the average population (or the population at midyear) is the crude death rate. In 1994, for example, the crude death rate per 1,000 population was 8.8 in the united states, 7.1 in Australia, etc. A death rate can also be tabulated according to age or cause. The ratio of deaths in an area to the population of that area; expressed per 1000 per year. (biology-online.org) 2. Usually measured by deaths per 1000 of population, the death rate is the number of a species which die, usually measured along side the birth Rate to determine long term population trends. (biology-online.org) 3. The ratio of deaths to the population of a particular area during a particular period of time, usually calculated as the number of deaths per one thousand people per year. (Google Dictionary) See also Mortality...

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Deciduous

/diˈsijo͞oəs/ Adjective 1. Means “falling off at maturity” or “tending to fall off”, and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe. In a more general sense, deciduous means the dropping of a part that is no longer needed, or falling away after its purpose is finished. (wikipedia.org) 2. Refers to a plant (usually a tree or shrub) that sheds its leaves at the end of the growing season. (biology-online.org) 3. Denoting the milk teeth of a mammal, which are shed after a time. (Google Dictionary) 4. Describing a part that falls off, or is shed, at a particular time or stage of development. (biology-online.org) Word origin: From Latin dēciduus (“falling down or off”), from dēcidō (“fall...

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Decussation

Noun 1. Used in biological contexts to describe a crossing. (In Latin anatomical terms the form decussatio is used, e.g. decussatio pyramidum). In anatomy the term chiasma or chiasm means much the same as decussation. (wikipedia.org) 2. A crossing or intersection of lines etc. so as to form an X-shape. (wiktionary.org) Syn: Chiasma, chiasm Word origin: Latin decussatus, crossed like the letter...

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Denonvilliers’ fascia

Noun 1. The fascia at the floor of the rectovesical pouch of the peritoneum, separating the prostate and the base of the urinary bladder from the rectum. (biology-online.org) 2. A membranous partition at the lowest part of the rectovesical pouch. It separates the prostate and urinary bladder from the rectum. It consists of a single fibromuscular structure with several layers that are fused together and covering the seminal vesicles. (wikipedia.org) Syn: Rectoprostatic fascia Word origin: Named after French anatomist and surgeon Charles-Pierre...

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Struggling in Biology?

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