Gonads

gonads
the reproductive organs in which the germ cells are found and the gametes produced; in humans, they are the ovaries and testes
Source: Jenkins, John B. 1990. Human Genetics, 2nd Edition. New York: Harper & Row ...
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gonads The male and female sex organs.
Gondwana Name applied to the ancient (Paleozoic-early Mesozoic) southern hemisphere supercontinent that rifted apart to form present-day Antarctica, India, Africa, Australia, and South America.
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gonads
[Gk. gone, seed]
The male and female sex organs; the gamete-producing organs in most animals.
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gonads Glands responsible for the production of gametes and where certain gonadal hormones are produced. These consist of the ovaries in females and the testes in males.
gonangium Reproductive zooid of hydroid colony (Cnidaria).
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In higher animals, ova are produced by female gonads (sexual glands) called ovaries and all of them are present at birth in mammals, and mature via oogenesis.
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For example, the embryo must decide whether its embryonic gonads will develop as testes or ovaries. Once it makes that decision the embryonic gonads secrete hormones that determine the fate of the external genitalia.
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Spermatogenesis refers to the creation, or genesis, of sperm cells, which occurs in the male gonads or testes. Sperm cells develop initially from germ stem cells known as spermatogonia .
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A gene, normally found on the Y chromosome in mammals, that directs the indeterminate gonads toward development as testes. See testis-determining factor.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z ...
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The PGCs migrate into the part of the developing embryo that will go on to form the gonads (ovaries or testes).
Exceptions to Weismann's Theory
The distinction between germline and soma exists only in animals.
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clitellum -- In annelids, a swelling of the body towards the head of the animal, where the gonads are located. Both oligochaetes and leeches have a clitellum.
cnidocyst -- The "stinging cell" of a cnidarian.
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germ cell [L. germinis - bud, offshoot] A cell found within the gonads that gives rise to a gamete.
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Presence of 2 or more cell lines that differ in genetic makeup among gametes (germ cells); implies risk of transmission of mutations present in the gonads to offspring. Cf. mosaicism
Related Terms: Gamete ...
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