Semen is a fluid secreted by the male gonads and functions as a transport medium for spermatozoa
- There are three main components of the male reproductive system that are responsible for the production of semen
Epididymis
- The epididymis functions to concentrate sperm that is produced in the seminiferous tubules by removing testicular fluids
- The epididymis also serves as the location where sperm mature and develop a capacity to ‘swim’
Seminal Vesicle
- The seminal vesicle adds nutrients (including fructose), which provide the energy needed for the sperm to ‘swim'
- It also secretes prostaglandins, which trigger uterine contractions that help move the sperm towards the egg
Prostate Gland
- The prostate gland secretes alkaline fluids which help to neutralise vaginal acids
- A localised pH change from (roughly) 4 to 6 functions to assist sperm motility
Structures Contributing to Semen Production
Male Sex Hormones
The production of sperm (and as a consequence, semen) is controlled by three key hormones – FSH, LH and testosterone
- FSH and LH are produced by the brain (anterior pituitary), whereas testosterone is produced by interstitial (Leydig) cells
FSH
- Initiates spermatogenesis by triggering the first meiotic division of spermatocytes
- Also activates Sertoli cells, which provide nourishment for cells undergoing spermatogenesis
LH
- Triggers the production of testosterone by Leydig cells in the interstitial tissue
Testosterone
- Completes spermatogenesis by triggering the second meiotic division of spermatocytes
- Stimulates the differentiation of spermatids to form mature spermatozoa
Hormonal Control of Male Reproduction
