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Anatomy of male reproductive system
- pair of testes that produce sperm and hormones
- systems of tubules to transport sperm to outside
- seminiferious tubules
- epididymis
- Vas derens
- penis to transport sperm into female
- accessory glands to secrete fluid into the urethra
- seminal vesicles
- bulbourethral glands (Cowper's glands)
- prostate gland
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Spermatogenesis
- complex process for a simple purpose - to propagate life by combining male and female chromosomes
- begins at puberty and lasts until death (in healthy males)
- semen typically contains between 50-100 million sperm
- under control of the hypothalamic-pituitary-gonadal HPG axis
- phenotypic gender development during embryogenesis
- sexual maturation during puberty
- endocrine function of the testis: testosterone production in Leydig cells
- exocrine function of the testis: sperm production in Sertoli cells
- seminiferous tubules contain sperm at various developmental stages, while mature sperm stored in epididymis and vas deferens can live several weeks before ejaculation
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Seminal vesicles
- comprises ~60% of semen volume
- secretes alkaline fluid to neutralize acidity of male urethra and female reproductive tract
- secretions contain fructose (nourish sperm), prostaglandins (to stimulate uterine contractions and propel sperm toward fallopian tubes) and proteins (coagulation reaction in semen)
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Prostate gland
- about the size of a walnut located inferior to the urinary bladder encircling the utethra
- comprises ~25% of semen volume
- secretes a thin, milky-colored, alkaline fluid to enhance sperm motility and citric acid to nourish sperm and several protein-digesting enzymes such as prostate specific antigen (PSA)
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Bulbourethral glands (Cowper's glands)
- about the size of a pea located near the base of the penis on either side of the urethra
- comprises ~15% of semen volume
- secretes alkaline mucus-like fluid to neutralize acidity of urine residue in the urethra and acidity of the vagina
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