Seminal Vesicles
+ The pair of seminal vesicles are posterior to the
urinary bladder.
+ Contribute about 65-75% of the seminal fluid in
humans
+ Contain proteins, enzymes, fructose, mucus,
vitamin C, flavins, phosphorylcholine and
prostaglandins (involved in suppressing an
immune response by the female against the
foreign semen)
+ High fructose concentrations provide nutrient
energy for the spermatozoa as they travel
through the female reproductive system.
+ To produce, maintain and transport sperm (the
male reproductive cells) and protective fluid
(semen)
+ To discharge sperm within the female
reproductive tract
+ To produce and secrete male sex hormones
The entire male reproductive system is dependent on
hormones - chemicals that stimulate or regulate the activity of
cells or organs
+ Follicle Stimulating Hormone (FSH)- necessary for sperm
production.
+ Luteinizing Hormone (LH) – stimulates the production of
testosterone.
+ Testosterone- also important in the development of male
characteristics ( muscle mass and strength, fat distribution,
bone mass and sex drive).
+ Penis
+ Scrotum
PENIS
+
This is the male organ used in sexual
intercourse.
+
+
+
three parts:
-Root- attaches to the wall of the abdomen
-Shaft- the body
-Glans - cone-shaped part at the end of the penis.
Foreskin- loose layer of skin that covers the glans.
This skin is sometimes removed in a process called
circumcision. The opening of the urethra, is at the tip of the
penis.
The body of the penis is cylindrical in shape and
consists of three circular shaped chambers. This tissue
contains thousands of large spaces that fill with blood when
the man is sexually aroused.
+
Semen- the fluid which carries sperm during ejaculation..
SCROTUM
This is the loose and pouch-like sac of skin
which hangs posterior to the penis. Inside the
scrotum are the testicles, also called testes.
-to serve as climate control system for the testes
When extreme cold temperature is detected,
the scrotum contract which draws the testes closer to
the body.
When a hot temperature is detected in the
body, the scrotum relaxes to keep the testes away
from the body.
+ Epididymis
+ Vas deferens
+ Testes
This is the long,
coiled tube-like structure which
is located on the posterior of
each testicle.
-to transport and store sperm
cells which are produced inside
the testes.
-to nurture the sperm until it
matures.
During the arousal
stage of sexual activity, the
contractions of the genitals
force the sperm which are
contained in the fluid-like
semen into the vas deferens.
A muscular tube that
begins at the lower end of the
Epididymis and passes upward along
the side of the testis to become part
of the spermatic cord. It passes
through the inguinal canal, enters the
abdominal cavity, and courses over
the pelvic brim. From there, it
extends back into the pelvic cavity,
where it ends behind the urinary
bladder. Near its termination, it
becomes dilated into a portion called
the "ampulla." Just outside the
prostate gland, the tube becomes
slender again and unites with the duct
of a seminal vesicle.
Ejaculatory duct, the
fusion of prostate gland and the duct
of seminal vesicle.
These are the
oval-shaped organs found
inside the scrotum. They are
secured at either end by
what is termed as the
spermatic cord.
-to produce testosterone.
-to produce sperm cells.
Seminiferous tubules- tubes
masses which are coiled
together. These tubules
function
by
spermatogenesis.
SEMINAL
VESICLE
+ Prostate Gland
+ The prostate gland is a muscular gland that
surrounds the first inch of the urethra as it
emerges from the bladder.
+ The smooth muscle of the prostate gland
contracts during ejaculation to contribute to
the expulsion of semen from the urethra.
+ Stores and secretes a clear, slightly alkaline
fluid constituting up to one-third of the
volume of semen.
PROSTATE
GLAND
Bulbourethral Glands
+ The bulbourethral glands also called Cowper's
glands are located below the prostate gland and
empty into the urethra.
+ The alkalinity of seminal fluid helps neutralize the
acidic vaginal pH
+ For secretion of gelatinous seminal fluid that
helps lubricate the urethra for spermatozoa to
pass through, and to help flush out any residual
urine or foreign matter. (< 1% of semen)
+ It is serve to increase the mobility of sperm cells
in the vagina and cervix by creating a less viscous
channel for the sperm cells to swim through, and
preventing their diffusion out of the semen.
+ The components of semen come from two
sources: sperm, and "seminal plasma".
+ Seminal plasma is produced by contributions
from the seminal vesicle, prostate, and
bulbourethral glands.
+ Basic amines such as putrescine, spermine,
spermidine and cadaverine are responsible for
the smell and flavor of semen.
+ These alkaline bases counteract the acidic
environment of the vaginal canal, and protect
DNA inside the sperm from acidic denaturation.
+ A spermatozoa are the haploid cell that is the
male gamete.
+ Contribute half of the chromosome number of
an individual
+ The sperm is the main reproductive cell in males.
+ The sperms differ in that each carry a set of
chromosomes dividing each into either a male, or
female sperm.
+ The female sperm also differ phenotypically in
that they have a larger head in comparison to the
male sperms. This contributes to the male sperm
being lighter, and therefore faster and stronger
swimmers than their female counterparts
although statistically there is still a 50% chance of
an either XY or XX embryo forming.
Tail flagellates - which propels the sperm cell by
rotating like a propeller, in a circular motion
Mitochondria in midpiece – for ATP generation
Nucleus – carries the genetic material
Acrosome – releases enzyme to weaken the
thick shell formed by glycoproteins (zona
pellucida)
Capacitation – process in which sperm develop the
capability to fertilize
Hypermotility - change in beat frequency and
amplitude of sperm motility
Acrosome Reaction - lysosomal enzymes
contained within the acrosome are released,
causing alteration of the sperm head plasma
membrane and weaken the shell, allowing the
sperm cell to penetrate it and reach the plasma
membrane of the egg.
1. Adequate motility to traverse the female
genital tract.
2. Ability to recognize and bind to the ovum and
its investments.
3. Ability to penetrate the zona pellucida.
4. Ability to fuse with the plasma membrane of
the ovum.
+ The most important laboratory test in evaluating
+
+
+
+
the fertility potential in a man is the semen
analysis.
]The following are the normal parameters.
Volume
2-5 cc
Sperm density
>20 million/cc (avg. 50-60)
Motility
>60%
Morphology
Absence of WBC's, RBC's,
bacteria, agglutination
>60% normal forms
+ Azoospermia is the condition in which no
sperm are found in the ejaculate.
Cause of Azoospermia
– ductal obstruction
– impaired production of mature sperm
Tests to know the cause of Azoospermia
– The volume of semen may help identify the level
of obstruction, since small volumes, indicate
obstruction of the ejaculatory ducts.
– Testis biopsy will reveal the adequacy of sperm
production and the degree of sperm maturation.
• Gonadotropin-Releasing Hormone
• Luteinizing Hormone
• Follicle Stimulating Hormone
• Testosterone
+ Secreted by the hypothalamus to the pituitary
+ Released in pulses in average of 70-90 minutes
and have a half-life of 2-5 minutes
+ Variation in the pulse frequency regulates the
release of FSH and LH
+ Secreted by the pituitary gland in response to
GnRH
+ Stimulates the Leydig cells to produce
testosterone
+ Secreted by the pituitary gland
+ Stimulates the Sertoli cells to produce mature
sperm with the help of testosterone
+ Stimulates the protein synthesis in Sertoli cells
by stimulating cAMP and protein kinases
+ Inhibited by inhibin produced by the Sertoli
cells
+ Important in sperm production
+ Male hormone and androgen produced by the Leydig cells
+ Masculinization of internal and external reproductive tissues
+
+
+
+
+
+
– Promotes the growth of the penis and scrotum
Pubertal changes
Enables retraction of foreskin during puberty
Binds with the andogen-binding protein produced by the
Sertoli cells
Testosterone aromatase Estradiol (E2)
Testosterone 5 α reductase Dihydrotestosterone (DHT)
Inhibits the production of LH and GnRH
- Stimulated by the androgens
1. Motivation – mainly olfactory inputs;
motivation to mate
-Androgen binds to amygdala
2. Performance – mainly visual inputs; mating
performance
-Androgen binds to preoptic area
*Castration reduces motivation and performance
Male Reproductive System
+ Penile erection
- a physiological phenomenon where the
penis becomes enlarged and firm
- complex interaction of psychological,
neural, vascular and endocrine factors, and
is usually, though not exclusively,
associated with sexual arousal
How an erection happens
+
Touch, sights, sounds, erotic memories and fantasies cause sexual excitement.
+
These stimuli increase signal output from a part of the brain called the paraventricular nucleus.
These signals then pass through special autonomic nerves in the spinal cord, the
pelvic nerves and the cavernous nerves that run along the prostate gland to reach
the corpora cavernosa and the arteries that supply them with blood.
+
+
In response to these signals, the muscle fibres in the corpora relax, allowing blood
to fill the spaces between them.
+
Muscle fibres in the arteries that supply the penis also relax, and there is an eightfold increase in blood flow to the penis. The increased blood flow expands the
corpora, then stretches the surrounding sheath (the tunica).
+
As the tunica stretches, it blocks off the veins that take blood away from the
corpora cavernosa. This traps blood within the penis, the pressure becomes very
high and the penis becomes erect.
+
During an erection pressure in the penis is at least twice the pressure of blood in
the main circulation. This is possible because the muscles of the pelvic floor
contract around the base of the corpora cavernosa.
Cross-section of the penis showing
the position of the corpora
cavernosa.
+ changes in the blood vessels that lessen their
ability to deliver blood to the penis
+ problems with the nervous system that interferes
with the nerves that stimulate an erection
+ problems due to certain drugs such as SSRI
antidepressants, antihypertensives (blood
pressure pills), anticholinergics, corticosteroids
and others
+ hormone problems such as too much prolactin (a
pituitary hormone) or low testosterone
+ Viagra, Cialis or Levitra act to maintain a high
concentration of cGMP – should not be taken
with food and alcohol
+ 60% successful, work only if sexually excited
+ not successful with low testorone (nitric oxide
(NO) and cGMP)
+ testosterone replacement
+ Nocturnal erections
- rapid eye movement phase
- 7 times and 25% of sleep in young men
- erection is 70% of the normal (during
sexual arousal)
+ Morning erection
- not related to bladder fullness
- loss of morning erection may indicate low in
testosterone
+ sufficient level of stimulation = ejaculation
+ sympathetic nervous system – responsible for
semen production
+ semen ejected to urethra with rhythmic
contraction (10-15 contractions)
+ ejaculation cannot be stopped when
contraction started
+ contraction = 0.6 seconds interval with
increment of 0.1 seconds per contraction
+ immediately following an orgasm, during
which time they are unable to achieve
another erection, and a longer period again
before they are capable of achieving another
ejaculation
+ during this time a male feels a deep and often
pleasurable sense of relaxation, usually felt in
the groin and thighs
+ semen = 0.1 – 10 milliliters
+ adult semen volume is affected by the time
that has passed since the previous ejaculation
+ Hypospermia = low semen volume that may
be caused by ejaculatory duct obstruction
+ last ejaculation
+ stress levels
+ testosterone
+ Oligospermia – unusually low sperm count
+ Azoozpermia – absence of sperm from the
semen
+ first ejaculation = 12 months from the onset of
+
+
+
+
puberty (through nuctornal emission or
masturbation)
1mL of semen for the following 3 months
semen is typically clear = fail to liquify
semen liquifies – 12 -14 months after
1st ejaculation = 90% no sperm
Semen development during puberty
Time after first
ejaculation
(months)
Average volume
(milliliter)
Liquefaction
Average sperm
concentration
(million
sperm/milliliter)
0
0.5
Noa
0
6
1.0
Noa
20
12
2.5
No/Yesb
50
18
3.0
Yesc
70
24
3.5
Yesc
300
^a Ejaculate is jellylike and fails to liquify.
^b Most samples liquify. Some remain jellylike.
^c Ejaculate liquifies within an hour.
 a mild injury to the testicles can cause severe
pain, bruising, or swelling
 occur when the testicles are struck, hit,
kicked, or crushed, usually during sports or
due to other trauma
 testicular torsion-- when 1 of the testicles
twists around, cutting off the blood supply
 surgery is needed to untwist the cord and
save the testicle
 a varicose vein (an abnormally swollen vein)
in the network of veins that run from the
testicles
 usually not harmful, although in some people
it may damage the testicle or decrease sperm
production
 see his doctor if he is concerned about
changes in his testicles
 one of the most common cancers in men
younger than 40
 occurs when cells in the testicle divide
abnormally and form a tumor
 if it's detected early, the cure rate is excellent
 teen boys should be encouraged to learn to
perform testicular self-examinations
 inflammation of the epididymis, the coiled
tubes that connect the testes with the vas
deferens
 caused by an infection and results in pain and
swelling next to one of the testicles
 occurs when fluid collects in the membranes
surrounding the testes
 may cause swelling of the testicle but are
generally painless
 surgery may be needed to correct the
condition
 when a portion of the intestines pushes
through an abnormal opening or weakening of
the abdominal wall and into the groin or
scrotum
 may look like a bulge or swelling in the groin
area
 can be corrected with surgery
 a persistent, often painful erection lasting more
than four hours
 occurs when blood flows into the penis but is not
adequately drained
 treatment involves draining the blood using a
needle placed in the side of the penis
 Medications that help shrink blood vessels, which
decreases blood flow to the penis, also may be
used.
 surgery may be required to avoid permanent
damage to the penis
 bending of the penis during an erection due to
a hard lump called a plaque
 plaque often begins as a localized area of
irritation and swelling (inflammation), and can
develop into a hardened scar
 penile implant can be used in cases where
Peyronie's disease has affected the man's
ability to achieve or maintain an erection.
 non-surgical treatment for Peyronie's disease
involves injecting medication directly into the
plaque in an attempt to soften the affected
tissue, decrease the pain, and correct the
curvature of the penis.
 Vitamin E pills have also been shown to
benefit some men with Peyronie's disease.
 inflammation of the skin covering the head of
the penis
 most often in men and boys who have not
been circumcised
 Symptoms include redness or swelling, itching,
rash, pain, and a foul-smelling discharge
 If there is an infection, treatment will include
an appropriate antibiotic or antifungal
medication.
 In cases of severe or persistent inflammation,
a circumcision may be recommended.
 taking appropriate hygiene measures
 avoid strong soaps or chemicals, especially
those known to cause a skin reaction.
 a rare form of cancer, highly curable when
caught early
 occurs when abnormal cells in the penis divide
and grow uncontrolled. Certain benign (noncancerous) tumors may progress and become
cancer.
 Surgery to remove the cancer is the most
common treatment.
 condition in which the foreskin of the penis is
so tight that it cannot be pulled back
(retracted) to reveal the head of the penis
 treatment may include gentle, manual
stretching of the foreskin over a period of time
 Circumcision- the surgical removal of the
foreskin, often is used to treat phimosis
 occurs when the foreskin, once retracted, cannot
return to its original location
 Treatment of focuses on reducing the swelling of
the glans and foreskin. Applying ice may help
reduce swelling, as may applying pressure to the
glans to force out blood and fluid
 an injection of medication to help drain the penis
may be necessary
 a surgeon may make small cuts in the foreskin to
release it
 circumcision- may be used as a treatment for
paraphimosis
+ Include
human
immunodeficiency
virus/acquired immunodeficiency syndrome
(HIV/AIDS), human papillomavirus (HPV, or
genital warts), syphilis, chlamydia, gonorrhea,
genital herpes, and hepatitis B
+ spread from one person to another mainly
through sexual intercourse
 HYPOSPADIAS - a disorder in which the urethra
opens on the underside of the penis, not at the
tip
 AMBIGUOUS GENITALIA - occurs when a child is
born with genitals that aren't clearly male or
female. In most boys born with this disorder, the
penis may be very small or nonexistent, but
testicular tissue is present. In a small number of
cases, the child may have both testicular and
ovarian tissue.
 MICRO PENIS- a disorder in which the penis,
although normally formed, is well below the
average size, as determined by standard
measurements