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89 Cards in this Set
- Front
- Back
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where do the sperm-producing testes lie? |
inside the scrotum |
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how is sperm delivered from the testes to the exterior body? |
through a system of ducts including: - epididymis - ductus deferens - ejaculatory duct - urethra |
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what are the accessory sex glands that empty their secretions into the ducts during ejaculation? |
- seminal vesicles - prostate - bulbo-urethral glands |
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what is the scrotum? |
•A hairy sac of skin & connectivetissue that hangs outside the pelvic cavity at the root of the penis.
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what divides the scrotum and why? |
a midline septum, providing a compartment for each testis |
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what does the scrotum help regulate? |
the temperature of the testes |
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what does sperm require to survive? |
a temperature 2-3 degrees lower than the core body temp |
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what happens in cold conditions? |
–In cold conditions the testes are pulledcloser to the pelvic floor & the warmth of the body by the cremaster muscle. |
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what happens in warmer conditions? |
–In warmer conditions the scrotal skinhangs loosely to increase the surface area for sweating. |
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what are the testes divided into? |
lobules |
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what do the lobules contain? |
seminiferous tubules |
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what two types of cells inhabit the seminiferous tubules? |
- spermatogenic (sperm-forming cells) - Sustentacular (Sertoli cells) |
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how is sperm moved from the tubules to the epididymis? |
•Smooth muscle in the walls of theseminiferous tubules contracts rhythmically to squeeze sperm & testicularfluid through the tubules & into the epididymis. |
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what is spermatogenesis? |
formation of sperm by meiosis |
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when does spermatogenesis begin? |
~ age 14 with production of 200-400 million sperm per day and continues throughout life |
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where does spermatogenesis? |
in the seminiferous tubules within the testes |
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what two hormones initiate and maintain spermatogenesis? |
- follicle stimulating hormone (FSH) - Testosterone |
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what other name is Sertoli cells known by? |
nurse cells |
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why? |
role in nurturing the developing sperm cells |
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what do they do? |
supports& provide nutrients for ~70 days while the cells undergo meiosis &develop into sperm producetesticular fluid for transport of sperm controlrelease of sperm into lumen of the seminiferous tubule |
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what does the flattened, pointed head of the sperm contain? |
the nucleus with 23 chromosomes |
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what is the acrosome? |
•cap-likevesicle containing enzymes to help the sperm penetrate the secondary oocyte forfertilization |
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what does the midpiece contain? |
mitochondia |
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what do the mitochondria provide? |
energy so that the tail can propel the sperm through the female reproductive tract |
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name the 4 parts of hormonal control of spermatogenesis? |
- from puberty the hypothalamus increases secretion of GnRh - GnRH stimulate anterior pituitary to increase secretion of LH and FSH - LH stimulates interstitial (Leydig) cells to secrete testosterone - FSH stimulate (along with testosterone) spermatogenesis |
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what does testosterone do? |
- controls growth, development, functioning and maintenance of sex organs. - stimulates sperm maturation, bone growth and protein synthesis. - development of male secondary sex characteristics. |
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what happens as levels of testosterone rise? |
they create negative feedback to reduce production of GnRH by the hypothalamus |
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name the 3 types of teste cells: |
1. spermatogenic cells 2. Sertoli cells 3. interstitial (Leydig cells) |
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functions of spermatogenic cells: |
- located in the walls of the seminiferous tubules - produce sperm cells |
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functions of Sertoli cells: |
- nourish developing sperm - control release of developing sperm into the lumen of the seminiferous tubule |
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functions of interstitial cells: |
- located in spaces between adjacent seminiferous tubules - secrete testosterone |
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what is the most common form of cancer in males aged 15-35 years? |
testicular cancer |
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what are the clinical manifestations? |
painless, solid mass in the testis |
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best way to enable early intervention? |
self-detection |
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major risk factor? |
undescended testes |
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when are boys said to have undescended testes? |
boys born with one or more of the testes remaining in the abdominal cavity are said to have undescended testes. |
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how does this occur? |
embryonic development of the testes begins in the abdomen but the testes usually descend to the scrotum in the later weeks of pregnancy, if this doesn't occur, they are born undescended |
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where is the epididymis found? |
curves around the posterior surface of the testis |
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what does it contain? |
~ 6m coiled duct |
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functions of the epididymis? |
- site for sperm to mature and gain mobility over 14 days - stores sperm - propels sperm into ductus (vas) deferens by peristalsis during sexual arousal |
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how does the Ductus deferens transport sperm to the urethra from the epididymis? |
peristalsis |
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how long can the ductus deferens store sperm for? |
several months |
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what does the ductus deferens do initially? |
travels away from the scrotum through the spermatic cord to reach the pelvic cavity |
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what happens once in the pelvic cavity? |
it loops over the ureter and carries sperm around the posterior surface of the urinary bladder |
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what does the spermatic cord contain? |
•contains all structures passing to &from the testes:
–testicularblood vessels –autonomicnerves –lymphaticvessels –ductus(vas) deferens –cremastermuscle |
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what passes through the inguinal canal? |
One spermatic cord passes through theinguinal canal on each side.
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what are the seminal vesicles? |
a pair of pouch-like structurs |
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what do they do? |
add alkaline, viscous fluid to the sperm |
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what does it contain? |
fructose that sperm can use to produce ATP |
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what doe the ductus deferens lead to? |
the short ejaculatory duct |
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where is this duct? |
runs through the superior aspect of the prostate gland |
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what does the ejaculatory duct do? |
ejects sperm and seminal vesicle secretions into the urethra just before ejaculationq |
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what is the prostate gland? |
•A golf-ball sized gland that encirclesthe urethra just inferior to the urinary bladder |
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what does the prostate gland consist of? |
•Consists of 20 – 30 glands embedded insmooth muscle & connective tissue |
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what does the prostate do during ejaculation? |
smooth muscle contracts squeezing glandular secretions into the urethra via several ducts |
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what does this fluid do? |
activates sperm and accounts for up to 1/3 of the volume of semen |
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describe semen? |
- milky, slighly acidic (pH 6.5) - includes nutrients and several enzymes e.g. prostate-specific antigen (PSA) |
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clinical application related to prostate? |
- prostate cancer - benign prostatic hyperplasia |
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how is prostate cancer detected? |
- digital examination through anterior rectal wall - assessment of blood levels of PSA - ultrasound |
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what happens with benign prostatic hyperplasia? |
prostate doubles to quadruples in size |
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who does it affect? |
most males >60 years |
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what does it do? |
distorts urethra and urine flow |
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what are bulbourethral glands? |
pea-sized glands |
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what do they do? |
producea thick, clear, alkaline mucus which drains into the urethra & lubricatesthe male urethra during sexual excitement. Neutralises acidic urine |
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what is the urethra? |
a 20cm long passageway which passes through the prostate and muscles of the perineum |
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what is the function of the urethra? |
•Itcarries urine out of the bladder & propels semen along the length of thepenis for discharge during ejaculation |
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how does the body prevent urine from mixing with semen, and prevent semen entering the bladder? |
•Duringejaculation a smooth muscle sphincter at the base ofthe urinary bladder closes (involuntary/reflex action), preventing urine fromentering the urethra & preventing semen entering the urinary bladder |
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what two things constitute the the external male genitalia? |
the penis and scrotum |
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what does the penis consist of? |
•The penis consists of an attached root& free shaft which ends in an enlarged tip called the glans penis. |
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what is the foreskin? |
the skin covering the penis at distal end |
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what is circumcision? |
–circumcision is the removal of theforeskin for social, cultural or religious reasons, it may reduce someinfections. |
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what is the shaft of the penis composed of? |
three long cylindrical bodies of erectile tissue - two corpora cavernosa - one corpus spongiosum |
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what is erectile tissue? |
Erectile tissue is a spongy network ofconnective tissue & smooth muscle with vascular spaces |
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what happens during sexual excitement to the penis? |
During sexual excitement the vascularspaces fill with blood, causing the penis to enlarge & become rigid |
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what is the penis surrounded by? |
smooth muscle and elastic connective tissue |
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how much semen is released at ejaculation? |
~2.5 - 5mL |
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what is semen? |
a thick, milky white fluid mixture of sperm, testicular fluid, and accessory gland secretions |
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what does this liquid provide? |
•The liquid provides transport medium,nutrients & contains chemicals that protect& activate the sperm & facilitate their movement. |
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how much of semen is constituted by sperm? |
5-10% |
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semen has a pH of what? |
7.5 to neutralise acid pH of vagina |
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what do clotting factors in semen cause? |
•Clotting factors in semen cause it to coagulateafter ejaculation sothat it sticks to the wall of the vagina. Then fibrinolysin in semen liquefies it about 15 - 20 minutes later & thesperm begin their journey through the female reproductive tract |
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how many sperm are deposited into vagina? |
about 200 million |
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how many reach the secondary oocyte? |
200 |
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how long do sperm usually survive in the female reproductive tract for? |
48hrs but some survive longer |
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how long is the secondary oocyte viable for? |
~ 24 hours |
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when does fertilization usually occur? |
about 12-24hrs after ovulation |
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what does male fertility require? |
Malefertility requires the production of adequate numbers of normally formed sperm with normal motility |
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what may affect function of the seminiferous tubules? |
•Function of the seminiferous tubules maybe affected by X-rays, infections, toxins, malnutrition, & raisedtemperature. |
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age-related changes to male reproductive system? |
•The onset of puberty ~ 12-14 yrs ismarked by pulses of GnRH which trigger production of FSH & LH • •About age 55 a decline in testosteronelevels results in decreased muscular strength, fewer viable sperm &decreased sexual desire. –Butabundant sperm may be present in old age.• •Benign prostatic hyperplasia may cause frequenturination, decreased force of stream, bed-wetting & sensation of incompleteemptying |
