Transcript Document

MALE REPRODUCTIVE SYSTEM
1
Why do men have nipples?
We all start off as females!

Then the Y chromosome kicks in.
Causes the male characteristics to develop in the
womb. By then, the nipples have already formed.
FUN FACT
Lions have sex every 15 minutes for an entire
week. However, this only occurs every two years.
The pig has the longest orgasm; it can last up to
15 minutes.
2
Fun Facts: THINGS YOU
PROBABLY DIDN'T KNOW
ABOUT YOUR BODY
The average man's penis is three times the length of his thumb.
Human thighbones are stronger than concrete.
A woman's heart beats faster than a man's.
Women blink twice as often as men.
The average person's skin weighs twice as much as their brain.
Your body uses 300 muscles to balance itself when you are standing
still
If saliva cannot dissolve something, you cannot taste it.
Women reading this will be finished now
Men who read this are probably still busy checking their thumbs
3
The Male Reproductive System
Figure 24.1
4
The Scrotum – Containing the
Testes and Spermatic Cord
Figure 24.2
5
EMBRYONIC DEVELOPMENT OF
THE SCROTUM
7 Months in utero
The testis (singular is testis, plural is
testes) is retroperitoneal, located up high,
above the pubic symphysis.
The vas deferens is a tube that grows from
it on the superior edge. On its inferior
edge, a fibrous band called the
GUBERNACULUM is attached to the
testes and inserts onto the skin under
where the penis is developing.
6
7 Months
Parietal
peritoneum
Perineum
7
8 Months
The gubernaculum shrinks, and testes are
pulled down.
The perineum forms a pouch called the
VAGINAL PROCESS.
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8 months
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Birth
The vaginal process is pinched off, forming
the TUNICA VAGINALIS.
In the meantime, the vas deferens grows
upward and into the abdominal cavity.
The DARTOS MUSCLE (cutaneous) lines
the scrotum, and blends with the
CREMASTER MUSCLE.
The Dartos and cremaster muscles both
elevate the testes in the cold so they can stay
warm, and they relax in the heat to allow the
testes to descend to stay cool.
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11
Decent of the Gonads
Figure 24.29a-c
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Spermatic Cord
Vas deferens (ductus deferens)
Cremaster muscle
Spermatic (testicular) artery and vein
Pampiniform plexus (Nerves and lymphatic
vessels).
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The Male Reproductive System
The scrotum – skin and superficial fascia
surrounding the testes

Positioning provides an environment cooler
than body temperature.
14
Testes
The testes are the primary sex organs in the male,
not the penis, because they make testosterone,
which creates the male secondary sex
characteristics.
Secondary sex characteristics are deep voice,
facial hair, axillary and pubic hair, larger musculoskeletal mass, thyroid cartilage.
In order for sperm to be produced, the
temperature has to be 3˚ cooler than normal body
temperature.
To insure this lower temperature, the testes are
located outside of the body, in the scrotum
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(outside of the pelvis).
Problems at Birth
1. CONGENITAL INGUINAL HERNIA
 The vaginal process doesn’t close off completely,
and a piece of intestine protrudes through the
inguinal canal. Adults can get inguinal hernias
too.
INGUINAL HERNIA
 Inguinal hernias in adults are very common
(lifetime risk 27% for men, 3% for women), and
their repair is one of the most frequently
performed surgical operations.
 If you do heavy lifting, it increases the
abdominal pressure, and a piece of intestine
gets pushed into the inguinal canal. Requires
surgery to stich the fascia shut.
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Inguinal Hernia
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Problems at Birth
UNDESCENDED TESTES
Is when the
gubernaculum does not
pull the testes all the way
down into the scrotum.
Sperm will still be able to
exit from the body, male
sex hormones will still
circulate in the body, and
the testes will still have
adequate blood supply.
However, viable sperm
will not be produced.
Needs a surgery to pull
them down.
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21
Undescended Testes
In newborn boys, inguinal canal is still wide
open, and if they are cold, testes will disappear
up there. This is not the same thing as having
undescended testes. You have to check for
undescended testes in a warm environment.
As they get older, the testes sometimes pull up
with age (have to check for undescended testes
again before puberty).
To check for problems with the testes going
back up into the abdomen, the doctor feels the
scrotum, and asks the patient to cough. Should
be a little movement, but the testes should not
move all the way up.
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Structure of the Testes
The testes are enclosed in a serous sac –
the tunica vaginalis
Deep to that is the tunica albuginea –
fibrous capsule of the testes

Divides each testis into 250-300 lobules
Lobules contain 1-4 coiled seminiferous tubules
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The Testes
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Figure 24.3a
The Seminiferous Tubules
Seminiferous tubules


They are each 70 cm (2 feet) long.
All together, they stretch out to ½ a mile!
Function of seminiferous tubules is to
make sperm.


Spermatogenic cells – sperm-forming cells
Sertoli (Nurse) cells – support cells
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Spermatogenesis
Spermatogenesis – sperm formation

Begins at puberty – 100 million sperm per day
1,000 sperm per second are made
500 billion sperm in a lifetime
Each sperm cell contains 30,000 genes, and each
genetic code is slightly different

Cells differentiate and move toward the lumen
Stage 1 – replication of spermatocytes
Stage 2 – meiosis
Stage 3 –Spermatids differentiate into
spermatozoa
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Spermatogenesis
Figure 24.4b
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SPERMATOGENESIS
SPERMATOCYTES divide into more cells
which migrate down toward the lumen,
grow a tail (now they are called
SPERMATIDS), and get released into the
lumen.
When they are released and are freeswimming, they are then called
SPERMATOZOA.
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Spermatocytes
100 million sperm cells are produced each
day.
You need that many; below 70 million per
ejaculate is considered infertility.
Sperm cells are the smallest cells of the
body, but large in numbers.
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Seminiferous Tubule
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Sertoli cells (“Nurse cell”)
Surround spermatocytes
Their function is to nurture the developing
spermatocytes.


They produce hormones that direct
spermatogenesis.
Once meiosis has occurred and the
spermatocytes are haploid, they are
vulnerable to phagocytosis. The Sertoli cells
protect them from this.
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Spermatids
Sertoli cells
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Interstitial Cells (Leydig cells)
Between the seminiferous tubules are
groups of cells called INTERSTITIAL
CELLS, which produce testosterone.
They are stimulated by luteinizing
hormone, while the spermatocytes are
stimulated by FSH.
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Interstitial cells
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Testes Slide
Interstitial Cells
(make testosterone)
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Fun Fact
One teaspoon of semen contains 300
million sperm.
Human males have enough sperm cells in
5 ml of semen to fertilize the number of
eggs equal to 5x the population of the
USA.
60% of the sperm cells are imperfect and
can never make it to the egg. They might
have multiple flagella that do not propel
them forward.
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Fun Fact
Boy Or Girl? It's In The Father's Genes


Men inherit a tendency to have more sons or
more daughters from their parents.
This means that a man with many brothers is
more likely to have sons, while a man with
many sisters is more likely to have daughters.
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Fun Fact
What animal produces the most semen?
The Sperm Whale

Produces 100 gallons of semen per ejaculate!
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Epididymis
The seminiferous tubules come together to form
the EPIDIDYMIS, the tube of which is 5 meters
(the width of this room!).
The function of the epididymis is to allow sperm
to mature and to store them.
It takes 20 days for the sperm to go from
production to storage.
If sperm is not ejaculated, it will just die and be
phagocytized.
The epididymis has smooth muscles for
peristalsis during ejaculation to move the sperm
along.
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The Epididymis
Tube leading
out of the
epididymis
Figure 24.3a
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Spermatic Cord
The SPERMATIC CORD leaves the
epididymis and contains the spermatic
artery, vein, nerves, and the DUCTUS
(VAS) DEFERENS which is the tube that
carries the sperm out of the epididymis.
The Vas deferens is long, 45cm (2 feet).
It goes through the inguinal canal, loops
around urinary bladder and down the other
side.
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The Ductus (Vas) Deferens
Figure 24.1
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The Spermatic Cord
Figure 24.2
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Seminal Vesicles
Posterior to the urinary bladder are the SEMINAL VESICLES
The EJACULATORY DUCT meets up with the PROSTATIC URETHRA in
the prostate.
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Seminal Fluid
The functions of the seminal vesicles
(60%) and the prostrate (40%) are to
produce most of the seminal fluid (seminal
fluid plus sperm = semen).
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Functions of the Semen
Medium for sperm to swim in
Nutrients for sperm (fructose, NOT
sucrose or glucose)
Neutralizes acidity in vagina to allow
sperm to survive
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Prostate
The urethra goes through the middle
of the prostate, and the prostate
continues to grow throughout life.
PROSTATIC HYPERTROPHY

Can constrict the urethra, causing
retention of urine because it is hard to
urinate. Needs surgery to open.
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Terms
Urinary retention


When the urine cannot get out.
Usually due to prostatic hypertrophy.
Urinary incontinence



When the urine comes out involuntarily.
Usually due to incompetent urethral sphincter.
The person may need to wear adult diapers.
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Prostate
To check for hypertrophy or cancer of the
prostate, do a rectal exam.
The rectum is against the prostate, and the
rectum is moveable. A finger is placed in the
rectum and the prostate can be palpated ¾ of
the way around (only the anterior ¼ cannot be
palpated). It is checked for size and lumps, and
should be part of a routine physical after the age
of 50 (sooner if there is a family history of
prostate cancer).
If the prostate needs to be removed, there are
nerves that might be severed that run along it,
causing erectile dysfunction.
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Rectum is close to prostate
Figure 24.1
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Prostate Cancer
Clinicians often say that the male prostate
is like the female breast because both
glands often develop cancer.
Prostate cancer affects 10% of men. In
older men, it’s slow onset, not to worry.
But in younger men, it grows faster.
Radiation for prostate cancer involves
injecting beads into the prostate gland to
pull radiation to only that area.
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New Blood Test for
Prostate Cancer
An experimental blood test for prostate
cancer seems to work better than the
current PSA test -- and can tell whether
the cancer is spreading.
The new test looks for a protein which
occurs in relatively large amounts only in
prostate cancer cells.
It not only tells whether you have prostate
cancer, but what kind of prostate cancer
you have.
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Final Journey of the Sperm
The vas deferens picks up fluid from the
prostate, and the semen enters the
urethra.
It picks up more secretions from the
bulbourethral glands.
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BULBOURETHRAL GLANDS
At the base of the urethra
Secretes mucous during erection
Function is to lubricate the urethra for
sperm to swim in and neutralize pH from
urine there.


It allows the semen to flow and survive.
Only a small amount of fluid is produced.
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Bulbourethral Gland
Figure 24.1
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Clinical Considerations
VASECTOMY is the #1 birth control
method in the US.

An incision is made in back of the scrotum,
cut out a piece of the vas deferens. It is
possible to reverse it, but it is assumed
permanent. Only 1 in a million is
unsuccessful.
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Clinical Considerations
VASECTOMY REVERSAL


Men who have a vasectomy reversal within
three years of their original vasectomy are
much more likely to have success. Those who
wait longer than 10 years to have a reversal
are much less likely to have success.
If the reversal fails, a doctor can still get the
sperm using a needle: sperm can be
aspirated from the genitals, and stored for
later use.
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INFERTILITY
One of the most frequent causes of
infertility in males is low sperm count
and/or abnormal sperm.
Disease, radiation, chemicals, high testes
temperature, and drug abuse can also
contribute to this condition.
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Most common cause of infertility
In spermatic cord is a network of vessels.
The veins there can become varicose; this
is called a VARICOCELE. As they
expand, there is less blood flow,
temperature drops in testes leading to the
most common cause of male infertility.
Second most common cause of infertility is
STD (inflammation blocks vas deferens).
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PENIS WITHDRAWAL
AS BIRTH CONTROL
"Coitus interruptus," or withdrawal, is when a
man pulls out before ejaculating.
Unfortunately this method of contraception is
highly ineffective, because pre-ejaculatory fluid
does indeed contain sperm.
In fact, it is the first few drops of semen that
carry the highest concentration of sperm.
The failure rate of this method is about 28%. It
also leaves one at risk for sexually transmitted
diseases.
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PENIS WITHDRAWAL
AS BIRTH CONTROL
The pre-ejaculate ("COWPER’S FLUID"),
fluid emitted by the penis as soon as
erection occurs (prior to ejaculation),
contains spermatozoa (sperm cells), which
can easily cause pregnancy.
Any semen on the vulva can also migrate
into the female reproductive tract.
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PENIS WITHDRAWAL
AS BIRTH CONTROL
The vulva can also pick up sperm from a
previous ejaculation.
Therefore, one should wash away any
ejaculate from objects that might come
near the woman's vulva (e.g. hands and
penis, sex toys).
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PENIS WITHDRAWAL
AS BIRTH CONTROL
During the post
world war II era,
the most
widespread
contraceptive
strategy was the
withdrawal
method - and
this era was
known as the
"baby boom".
Go figure.
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Fun Facts
95% of the sperm are killed off in the vagina by the
acidity.
Most of the rest are attacked and killed by WBCs in the
uterus.
Only about a dozen sperm cells make it to the fallopian
tubes. It takes about 24 hours for them to swim there,
where they wait for the egg to arrive.
Male contraception pill
http://www.bbc.co.uk/news/health-18190352
Researchers develop prototype for male birth control
pill, http://fxn.ws/NHQJHO
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If you sometimes feel a little
useless or depressed, always
remember that YOU were once the
fastest and most victorious little
sperm out of millions!
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The Amazing Penis
This organ can vary in size from 1” to 6” in seconds, while
maintaining the integrity of the blood vessels, nerves, and
lymphatics.
THREE REGIONS OF THE PENIS
ROOT of the penis is in the perineum
BODY of the penis is the exposed region
GLANS is the tip of the penis.

PREPUCE (foreskin) surrounds the glans
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CIRCUMCISION
Circumcision is removal of the foreskin, exposing
the glans.
This is the most common surgical procedure
done in the US, although there is no medical
reason to have it done.
It is not done routinely anywhere in the world
except in Jewish and Muslim cultures for
religious reasons, and in Africa, where AIDS is
prevalent.
About 1/3 of the world’s male population is
circumcised, but hardly anyone from Europe,
Latin America, or Asia is circumcised.
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CIRCUMCISION
No major medical organization
recommends either universal circumcision
for all infant males (aside from the
recommendations of the World Health
Organization for parts of Africa), or
banning the procedure.
There is a complication rate of 1.5% in
newborns (bleeding, infection and the
removal of either too much or too little
foreskin).
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Cold and Warm Testes,
uncircumcised male
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Circumcised Penis
Glans
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Anatomical Position of the Penis
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Cross-Section of Penis
In cross-section, within the penis there are
three tubes (2 posterior) called
CYLINDERS OF ERECTILE TISSUE.
The posterior two are the CORPUS
CAVERNOSUM (Corpora cavernosum,
plural).
The anterior one is the CORPUS
SPONGIOSUM, within which is the
urethra.
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Cross-Section of Penis
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The
Penis
Figure 24.8a,
78b
The Penis
Figure 24.8a,
79b
Penile Erection
The erectile tissue in the corpora cavernosum is
lined by dense fibrous connective tissue which
extends into itself, creating vascular spaces
which can fill with blood, causing the penis to
become more rigid and expand.
The erection is due to vasodilation, with blood
moving into erectile bodies (tissue).
The corpus spongiosum doesn’t get as rigid or it
would squeeze urethra shut.
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Viagra
Medicine which causes vasodilation, but if
you have heart disease, it can give you a
heart attack.
An erection lets the arterial blood in, but
squeezes the veins shut so the blood can’t
leak out.
If Viagra (or anything else) causes an
erection for longer than four hours (called
priapism), the erection decreases the
blood flow, and the tissue is killed.
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Treatment for priapism
The first treatment for ischemic priapism is
"therapeutic aspiration." The urologist
sticks a needle into the side of the penis
and draws blood directly from the
cavernosum. The same needle is
sometimes used to inject saline solution
into the penis, which can help flush out the
remaining blood. Aspiration and irrigation
work around 25 percent to 30 percent of
the time.
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Treatment for priapism
Doctors can also inject drugs that constrict
the arteries and cut off penile blood flow.
Injections are given every few minutes for
about an hour.
In rare cases, an intractable erection will
resist both aspiration and drug injections.
In this case, the urologist performs a
surgical shunt.
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Treatment for priapism
The simplest type
of shunt involves
cutting a small hole
in the head of the
penis, then opening
oval windows in the
tips of the corpus
cavernosum.
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Other Problems with the Penis
Hypospadia is the most common
congenital abnormality of the urethra, and
is in males only.
The skin around the urethra does not
close all the way, and the urethra is open
to the outside of the body. It requires
surgical closure within one year of birth.
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Hypospadias
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PROBLEMS WITH MALE
DEVELOPMENT
Hypospadias: In
1/300 boys the
urethra doesn’t close
all the way, or is
opened on the body
of the penis.
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HYPOSPADIA
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Reproductive System Cancers
in Males
Testicular cancer



Affects 1 of 50,000 males
Cured in 95% of cases
Smoking pot linked to testicular cancer
risk, http://fxn.ws/RDGl0R
Prostate cancer


Slow-growing
Risk factors
Fatty diet
Genetic predisposition
90
Penile Carcinoma
The annual incidence is approximately 1 in
100,000 men in the United States.
Rarely seen in men under the age of 50
91
Puberty
(about age 13)
Male secondary sex characteristics




Appearance of pubic, axillary, and facial hair
Lengthening of vocal folds – deepening voice
Musculoskeletal system increases in mass
Sexual maturation – mature sperm in semen
92
There is more money being spent on
breast implants and Viagra today
than on Alzheimer's research.
This means that by 2040, there should be
a large elderly population with perky boobs
and huge erections and absolutely no
recollection of what to do with them.
93
94
• The American Medical Association has weighed in on the new health
care package.
The Allergists were in favor of scratching it,
but the Dermatologists advised not to make any rash moves.
The Gastroenterologists had sort of a gut feeling about it,
but the Neurologists thought the Administration had a lot of nerve.
Meanwhile, Obstetricians felt certain everyone was laboring under a
misconception,
while the Ophthalmologists considered the idea shortsighted .
Pathologists yelled, "Over my dead body!"
while the Pediatricians said, "Oh, grow up!"
95
• The Psychiatrists thought the whole idea was madness,
while the Radiologists could see right through it.
Surgeons decided to wash their hands of the whole thing
and the Internists claimed it would indeed be a bitter pill to swallow.
The Plastic Surgeons opined that this proposal would "put a whole
new face on the matter".
The Podiatrists thought it was a step forward,
but the Urologists were pissed off at the whole idea.
Anesthesiologists thought the whole idea was a gas,
and those lofty Cardiologists didn't have the heart to say no.
In the end, the Proctologists won out, leaving the entire decision up
to the ____holes in Washington .
96
Are computers male or female?
• Computers are male because: 1. In order to get their attention, you
have to turn them on. 2. They have a lot of data but are still
clueless. 3. They are supposed to help you solve your problems,
but half the time they ARE the problem. 4. As soon as you commit
to one, you realize that, if you had waited a little longer, you could
have had a better model.
Computers are female because: 1. No one but their
creator understands their internal logic. 2. The native language they
use to communicate with other computers is incomprehensible to
everyone else. 3. Even your smallest mistakes are stored in longterm memory for later retrieval. 4. As soon as you make a
commitment to one, you find yourself spending half your pay check
on accessories.
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Male reproductive system videos
•
•
•
CADAVER DISSECTION
http://www.dailymotion.com/video/x33m2k_male-reproductive-system1_shortfilms
http://www.dailymotion.com/video/x33m5g_male-reproductive-system-2_shortfilms
•
Histology of male reproductive system
http://video.google.com/videoplay?docid=1745918901226400161#
• Genital injuries send thousands to emergency care each year, study
shows, http://www.foxnews.com/health/2012/11/08/genital-injuriessend-thousands-to-emergency-care-each-year-study-shows/
•
Man jokingly takes pregnancy test, finds out he has testicular
cancer, http://www.foxnews.com/health/2012/11/08/man-jokingly-takespregnancy-test-finds-out-has-testicular-cancer/
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