Yeates W K
Arch Ital Urol Nefrol Androl. 1990 Mar;62(1):137-48.
Ejaculation is the final link of the male sexual function chain "Libido--Erection--Penetration--Achievement of Climax--Ejaculation". Each link is highly androgen-dependent. Although the initiation of a subsequent link is normally dependent on achievement of the previous link, each link has its own mechanisms, and can be made to occur in isolation. The basic requirements for ejaculation are the production of seminal fluid (mostly from the seminal vesicles) and its propulsion. The production of a normal volume of seminal fluid requires the presence of seminal vesicles and the maintenance of their secretion by androgens. The propulsion of seminal fluid is in 3 phases: I. Contraction of seminal vesicles; II. Closure of bladder neck (both due to T9-L2 sympathetic stimulation); III. Expulsion of semen from the bulb of the urethra (due to S2-S3 somatic stimulation). The coordination of these phases is probably at hypothalamic level. Failure of ejaculation may be classified into I. Deficiency of production of seminal fluid from (1) Absence of seminal vesicles or (2) Androgen deficiency from (a) Pituitary dysfunction or (b) Testicular interstitial-cell failure from a number of causes. Correction of androgen deficiency usually restores ejaculation.
射精是男性性功能链“性欲——勃起——插入——达到高潮——射精”的最后一环。每个环节都高度依赖雄激素。虽然后续环节的启动通常依赖于前一环节的达成，但每个环节都有其自身机制，且可单独发生。射精的基本要求是精液的产生（主要来自精囊）及其推进。产生正常量的精液需要精囊的存在以及雄激素对其分泌的维持。精液的推进分三个阶段：I. 精囊收缩；II. 膀胱颈关闭（均由于T9 - L2交感神经刺激）；III. 精液从尿道球部排出（由于S2 - S3躯体刺激）。这些阶段的协调可能发生在下丘脑水平。射精功能障碍可分为：I. 精液产生不足，原因包括(1) 无精囊或(2) 雄激素缺乏，后者又源于(a) 垂体功能障碍或(b) 多种原因导致的睾丸间质细胞功能衰竭。纠正雄激素缺乏通常可恢复射精功能。
