|
A sex organ or primary sexual characteristic, as narrowly defined, is any anatomical part of the body involved in sexual reproduction and constituting the reproductive system in a complex organism, especially the external sex organs; the external sex organs are also commonly referred to as the genitalia or genitals.〔(【引用サイトリンク】 publisher=''Collins English Dictionary'' )〕 Mosses, ferns, and some similar plants have gametangia for reproductive organs, which are part of the gametophyte. The flowers of flowering plants produce pollen and egg cells, but the sex organs themselves are inside the gametophytes within the pollen and the ovule. Coniferous plants likewise produce their sexually reproductive structures within the gametophytes contained within the cones and pollen. The cones and pollen are not themselves sexual organs. == Terminology == The Latin term ''genitalia'', sometimes anglicized as ''genitals'', is used to describe the externally visible sex organs, known as ''primary genitalia'' or ''external genitalia'': in male mammals, the penis and scrotum; and in female mammals, the clitoris and vulva. The other, hidden sex organs are referred to as the ''secondary genitalia'' or ''internal genitalia.'' The most important of these are the gonads, a pair of sex organs, specifically the testes in the male or the ovaries in the female. Gonads are the true sex organs, generating reproductive gametes containing inheritable DNA. They also produce most of the primary hormones that affect sexual development, and regulate other sexual organs and sexually differentiated behaviors. In general zoology, given the great variety in organs, physiologies, and behaviors involved in copulation, male genitalia are more strictly defined as "all male structures that are inserted in the female or that hold her near her gonopore during sperm transfer"; female genitalia are defined as "those parts of the female reproductive tract that make direct contact with male genitalia or male products (sperm, spermatophores) during or immediately after copulation".〔Eberhard, W.G., 1985. Sexual Selection and Animal Genitalia. Harvard University Press〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sex organ」の詳細全文を読む スポンサード リンク
|