Physiology
Sperm production and transport
Updated: 3 October 2026
Reading time · 1 min See illustrations
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3D animation1:38
Overview of the Male Reproductive System
Merck Manual Consumer Version · Video in English
Subject illustration · NIDDK / NIH
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01The role
Testicles produce sperm under hormonal control.
02The mechanism
Maturation continues in the epididymis; the vas deferens carries sperm during ejaculation.
03Coordination
The prostate and seminal vesicles add secretions making up much of the semen.
04Key point
Fertility is not measured by semen volume alone. Semen analysis needs the couple’s context and may be repeated.
Medical references
This general information does not replace a consultation. Tests and treatments are selected for each individual; they are not a routine checklist.
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