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Male Reproductive System (pg 6)
Male Reproductive System (pg 6)
• Functions: Produce and transport sperm, introduce sperm into female vagina, and produce hormones responsible for development of secondary male sex characteristics
Testes
• Produce sperm
Testes
• Produce sperm• Begin development high in abdominal cavity.
Around 2 months before birth, they descend into the scrotum
Testes
• Produce sperm• Begin development high in abdominal cavity.
Around 2 months before birth, they descend into the scrotum
• Testes are around 3 degrees cooler than body temperature. Necessary for production of viable sperm.
Testes
• Produce sperm• Begin development high in abdominal cavity.
Around 2 months before birth, they descend into the scrotum
• Testes are around 3 degrees cooler than body temperature. Necessary for production of viable sperm.
• Cremaster muscle contracts when cold to bring the testes closer to the body for warmth
Duct system
• Once produced in the testes, sperm move through a series of ducts to reach the outside of the body. The ducts are the epididymis, ductus deferens, ejaculatory duct, and urethra
Epididymis
• Long tube (6 meters). Tightly coiled to form comma-shaped organ that sits on top of testes
Epididymis
• Long tube (6 meters). Tightly coiled to form comma-shaped organ that sits on top of testes
• When sperm leaves testes, they are unable to “swim” and incapable of fertilizing an egg
Epididymis
• Long tube (6 meters). Tightly coiled to form comma-shaped organ that sits on top of testes
• When sperm leaves testes, they are unable to “swim” and incapable of fertilizing an egg
• As sperm slowly move through the epididymis, they mature and become fertile
Ductus deferens (vas deferens)
• Tube that carries sperm from the epididymis to the ejaculatory duct
Ductus deferens (vas deferens)
• Tube that carries sperm from the epididymis to the ejaculatory duct
• Vasectomy: surgical procedure that severs the ductus deferens for birth control
Ejaculatory duct
• Ductus deferens joins duct from the seminal vesicle to form a short ejaculatory duct
Ejaculatory duct
• Ductus deferens joins duct from the seminal vesicle to form a short ejaculatory duct
• Passes through the prostate gland and into the urethra
Urethra
• Passageway for urine and semen
Urethra
• Passageway for urine and semen• 3 regions
1. Prostatic urethra: passes through prostate gland. Receives fluids from ejaculatory duct and prostate
Urethra
• Passageway for urine and semen• 3 regions
1. Prostatic urethra: passes through prostate gland. Receives fluids from ejaculatory duct and prostate2. Membranous urethra: short region that passes through the pelvic floor
Urethra• Passageway for urine and semen• 3 regions
1. Prostatic urethra: passes through prostate gland. Receives fluids from ejaculatory duct and prostate2. Membranous urethra: short region that passes through the pelvic floor3. Spongy (penile) urethra: extends the length of penis and opens to outside
Penis
• Male copulatory organ. Transfers sperm to the vagina
Penis
• Male copulatory organ. Transfers sperm to the vagina
• Parts: Root, shaft, glans (head)
Penis
• Male copulatory organ. Transfers sperm to the vagina
• Parts: Root, shaft, glans (head)• Contains erectile tissue that can become
engorged with blood and become rigid
Accessory Glands: secrete fluids that enter the urethra
Accessory Glands: secrete fluids that enter the urethra
• Seminal vesicles: glands posterior to urinary bladder. Produce viscous fluid that contains fructose, which serves as an energy source for sperm
Accessory Glands: secrete fluids that enter the urethra
• Seminal vesicles: glands posterior to urinary bladder. Produce viscous fluid that contains fructose, which serves as an energy source for sperm
• Prostate: Walnut sized. Encircles the urethra. Produces thin, milky, alkaline fluid that enhances the motility of sperm
Accessory Glands:• Seminal vesicles: glands posterior to urinary
bladder. Produce viscous fluid that contains fructose, which serves as an energy source for sperm
• Prostate: Walnut sized. Encircles the urethra. Produces thin, milky, alkaline fluid that enhances the motility of sperm
• Bulbourethral gland: pea sized. Produces pre-ejaculatory fluid, which provides lubrication and works as a buffer to prevent chemical reaction between acidic urine and basic semen
Semen
• Slightly alkaline (pH = 7.5)
Semen
• Slightly alkaline (pH = 7.5)• 60% of volume comes from seminal vesicles,
40% from prostate, <1% from sperm and bulbourethral glands
Semen
• Slightly alkaline (pH = 7.5)• 60% of volume comes from seminal vesicles,
40% from prostate, <1% from sperm and bulbourethral glands
• Contains 50 – 150 million sperm per mililiter