Sex organ: Difference between revisions
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==Development== |
==Development== |
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{{Main|Development of the urinary and reproductive organs}} |
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In typical [[prenatal development]], sexual organs originate from a common [[anlage]] anatomy during early [[gestation]] and differentiate into male or female variations. The [[SRY]] [[gene]], usually located on the [[Y chromosome]] and encoding the [[testis determining factor]], determines the direction of this differentiation. The absence of it allows the gonads to continue to develop into ovaries. |
In typical [[prenatal development]], sexual organs originate from a common [[anlage]] anatomy during early [[gestation]] and differentiate into male or female variations. The [[SRY]] [[gene]], usually located on the [[Y chromosome]] and encoding the [[testis determining factor]], determines the direction of this differentiation. The absence of it allows the gonads to continue to develop into ovaries. |
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Revision as of 07:41, 5 August 2007
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A sex organ, or primary sexual characteristic, as narrowly defined, is any of those anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; namely:
- Male: testicles, penis, prepuce, scrotum, prostate, seminal vesicles, epididymis, Cowper's glands
- Female: ovaries, clitoris, vulva, labia, Skene's gland, Bartholin's glands, vagina, cervix, uterus, Fallopian tube.
The Latin term genitalia, sometimes anglicized as genitals and genital area, is used to describe the externally visible sex organs, known as primary genitalia or external genitalia: in males the penis and scrotum, in females the clitoris and vulva, including the genital cleft, labia majora, and external labia minora.
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.
A more ambiguously defined term is erogenous zone, subjectively, any portion of the body that when stimulated produces erotic sensation, but always prominently including the genitalia.
Development
In typical prenatal development, sexual organs originate from a common anlage anatomy during early gestation and differentiate into male or female variations. The SRY gene, usually located on the Y chromosome and encoding the testis determining factor, determines the direction of this differentiation. The absence of it allows the gonads to continue to develop into ovaries.
Thereafter, the development of the internal reproductive organs and the external genitalia is determined by hormones produced by certain fetal gonads (ovaries or testes) and the cells' response to them. The initial appearance of the fetal genitalia (a few weeks after conception) is basically feminine: a pair of "urogenital folds" with a small protuberance in the middle, and the urethra behind the protuberance. If the fetus has testes, and if the testes produce testosterone, and if the cells of the genitals respond to the testosterone, the outer urogenital folds swell and fuse in the midline to produce the scrotum; the protuberance grows larger and straighter to form the penis; the inner urogenital swellings grow, wrap around the penis, and fuse in the midline to form the penile urethra.
Each sexual organ in one sex has a homologous counterpart in the other one. See a list of homologues of the human reproductive system.
In addition, sexual differentiation includes differences in brain structure and function, affecting, but not absolutely determining, behavior. Secondary sexual characteristics such as patterns of pubic and facial hair, and female breasts emerge at puberty.
Anatomical terms related to sex
The following is a list of anatomical terms related to sex and sexuality:
- areola
- Bartholin's gland — breast — bulbospongiosus muscle — bulbourethral gland
- cervix — Cleft of Venus — clitoris — common penile artery — corona glandis — corpora cavernosa — corpus cavernosum — corpus spongiosum — Cowper's glands — cremaster muscle
- dartos muscle — ductus deferens
- ejaculatory duct — endometrium — epididymis
- Fallopian tube — foreskin — frenulum — frenulum preputii penis — frenulum labiorum pudendi — frenulum clitoridis — frenum — fundiform ligament
- G-Spot — Gartner's duct — genital tubercle — genitofemoral nerve — glans — glans penis — Gräfenberg spot
- hymen
- internal pudendal artery — ischiocavernosus muscle
- labium — labia majora — labia minora
- mammae — mammary gland — meatus — mons pubis — mons veneris — Mullerian duct
- nipple
- ovary — ovum — oviducts
- penis — perineum — prepuce — prostate — pubic hair — pubic symphysis — pubococcygeus muscle — pudendal nerve
- raphe — ridged band
- scrotum — seminal vesicles — semeniferous tubules — Skene's glands — spermatozoon — spermatic cord — sphincter urethrae membranaceae — splanchnic nerves
- testes — testicle — tunica albuginea
- urethra — urethral sponge — urogenital diaphragm — uterus
- vas deferens — vagina