Male Reproductive Systems: For Discussion: True or False

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Male Reproductive Systems For Discussion True
or False?
1. Sperm cells in the female reproductive tract
are considered by a womans immune system to
be non-self and are attacked by her
phagocytic white blood cells.
True
2. Sperm cells are considered by a mans immune
system as non-self and are attacked by a
mans own white blood cells.
True

• A woman, in her reproductive lifetime, has the
  potential to produce about 500,000 eggs, but she
  will only ever use about 500.

True
4. The average man, in a single average
ejaculation of semen, emits more reproductive
cells than the average woman produces in her
reproductive lifetime.
True, about 420 million per average ejaculate,
he produces about 4 million/hour
5. Only one sperm may fertilize an egg in humans.
True
6. Only about 1 in 42,000 sperm, or 0.00238 of
the sperm in an average ejaculation reach
the egg.
True
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The Male Reproductive System
-produces and maintains sperm cells and
transports them, along with their supporting
fluids, into the female reproductive tract
-produces and secretes male sex hormones
Ureter
Large intestine
Urinary bladder
Seminal vesicle
Pubic bone
Penis
Ejaculatory duct
Ductus (vas) deferens
Prostate gland
Urethra
Corpus cavernosum
Bulbourethral (Cowpers) gland
Corpus spongiusum
Anus
Glans penis
Epididymus
Prepuce (foreskin)
Scrotum
Testis
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The Male Reproductive System
I. Testes
-male primary sex organs
-produce sperm and male sex hormones
-housed within the scrotum
-form within the abdominal cavity, stimulated by
testosterone to descend into the scrotum 1-2
months before birth through the inguinal canal,
led by the gubernaculum, which anchors the
testis to the bottom of the scrotum
Ever hear of a gubanatorial election?
Its from the Latin for steersman!
Rx Inguinal hernia
-in about one-fourth of males, the pouch of
peritoneum that moves through the inguinal canal
remains open allowing for a loop of intestine
to be forced through the inguinal canal under
great pressure, like getting dogpiled in a
football game
vaginal process
-if the loop becomes constricted in the inguinal
canal, the blood supply can be cut off, creating
a strangulated hernia, in which the tissue will
die without prompt surgical treatment
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I. Testes
Rx Cryptorchidism
-failure of one or both of the testes to descend
into the scrotum, which has an internal
temperature of about 94 F
-internal body temperature (98.6 F) is too high
for sperm to survive
-sperm-producing cells degenerate, leading to
infertility
-leads to increased risk of testicular cancer
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I. Testes
-structure
A. Tunica albuginea
-tough, white fibrous capsule surrounding each
testis and subdividing the inside of each testis
into about 250 lobules
B. Seminiferous tubules
-each lobule contains 1-4 coiled seminiferous
tubules, each about 70 cm long (700 total feet),
which unite to form the rete testis, which in
turn form ducts that empty in the epididymus,
which continues into the ductus deferens
Ductus deferens
Epididymus
-cells with the walls of the seminiferous
tubules called spermatogonia divide by mitosis
when stimulated by testosterone to produce
primary spermatocytes, which divide by meiosis
to produce spermatozoa
Rete testis
Seminiferous tubules
Tunica albuginea
Spermatozoa
Spermatogonia
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I. Testes
B. Seminiferous tubules
Spermatozoa
Sustentacular cells
Nucleus of sustentacular cell
Spermatid
Secondary spermatocyte
Primary spermatocyte
The sustentacular cells and the tight junctions
between them form the blood-testis barrier, which
prevents access to the sperm by the white blood
cells, which would attack them as non- self
Tight junction
New Type B spermatogonium
New Type A spermatogonium
Basement membrane
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I. Testes
B. Seminiferous tubules
1. Spermatogenesis
-creation of sperm within the walls of the
seminiferous tubules
-beginning at puberty, an increase in
testosterone triggers meiosis of the primary
spermatocyte
Meiosis I Reduction division
Meiosis II Mitotic division
Maturation
Primary spermatocyte
Secondary spermatocytes
spermatids
spermatozoa
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I. Testes
B. Seminiferous tubules
1. Spermatogenesis
-from puberty to old age, a man can produce
about 100 million sperm per day, average sperm
count in semen is 120 million sperm per mL, less
than 20 million sperm per mL infertility
During synapsis of homologous chromosomes during
Prophase I, crossing over occurs, resulting in
new genetic variation
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I. Testes
B. Seminiferous tubules
1. Spermatogenesis
a. Sperm structure
i. Head
-made up of the acrosome, which allow the sperm
to digest its way into the egg, and a highly
compacted nucleus, which contains 23 chromosomes
in its diffuse state chromatin
Acrosome
Head
Nucleus
ii. Midpiece
-contains mitochondria to provide energy to lash
the tail
Midpiece
iii. Tail
-a single flagellum
Tail (flagellum)
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I. Testes
Rx Testicular Cancer
-accounts for only about 1 of the cancers in
men in the U.S., causing about 390 deaths each
year
-most common type of cancer in young men, ages
15-34, arises from epithelial tissue of tubules
Seminiferous tubules
-treated with the surgical removal (orchiectomy)
of the affected testicle and radiation and/or
chemotherapy to prevent reoccurence
-cured 95 of the time
-incidence is on the rise for all men, incidence
is the highest among white men, especially those
of Scandanavian descent
Interstitial cells
C. Interstitial Cells
-cells of Leydig
-lie between seminiferous tubules in testes
-produce and secrete into the bloodstream the
male sex hormones