Download Seminal vesicle

E.Mangoli
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 The
seminal vesicles are paired, elongate,
and highly folded tubular glands located on
the posterior wall of the urinary bladder,
parallel to the ampulla of the ductus
deferens.
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
The secretion of the seminal vesicles is a whitish yellow,
viscous material.

It contains:
 fructose, which is the principal metabolic substrate for
sperm
 amino acids,
 ascorbic acid,
 prostaglandins: E, A, B, F
 coagulating factor
 semenogelin 1: sperm motility inhibitor, which is
cleaved by PSA (proteolytic enzyme) after ejaculation
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 Contraction
of the smooth muscle coat of
the seminal vesicles during ejaculation
discharges their secretion into the
ejaculatory ducts and helps to flush
sperm out of the urethra.
 The
secretory function and morphology of
the seminal vesicles are under the control
of testosterone.
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 The
prostate is the largest accessory sex
gland of the male reproductive system.
 The
gland is located in the pelvis, inferior to
the bladder, where it surrounds the prostatic
part of the urethra.
 The
prostate is composed of approximately
70% glandular elements and 30%
fibromascular stroma.
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
It consists of 30 to 50 tubuloalveolar glands
arranged in three concentric layers:
an inner mucosal layer,
 an intermediate submucosal layer,
 a peripheral layer containing the main prostatic
glands.
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The glands of the mucosal layer secrete directly
into the urethra; the other two layers have ducts
that open into the prostatic sinuses located on
either side of the urethral crest on the posterior
wall of the urethra.
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 The
adult prostatic parenchyma is divided
into four anatomically and clinically distinct
zones:
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peripheral zone
central zone
transitional zone
periurethral zone
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 The
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prostate gland secretes:
prostatic acid phosphatase (PAP),
fibrinolysin, (serves to liquefy the semen)
citric acid,
prostate-specific antigen (PSA). (a serine
protease)
polyamines: proliferation and growth
calcium,
phosphate ion,
clotting enzyme,
Profibrinolysin,
zinc.
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 The
elevated levels of PSA are directly
related to increased activity of the prostatic
cancer cells.
 Increased
blood levels of both PAP and PSA
are used as markers of the presence and
progression of the disease.
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
The bulbourethral glands secrete preseminal
fluid

The paired bulbourethral glands (Cowper's
glands) are pea-sized structures located in the
urogenital diaphragm.

The duct of each gland passes through the
inferior fascia of the urogenital diaphragm and
joins the initial portion of the penile urethra.

The glands are compound tubuloalveolar glands
that structurally resemble mucus secretory
glands.
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 The
clear, mucuslike glandular secretion
contains considerable amounts of :
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galactose and galactosamine,
galacturonic acid,
sialic acid,
methylpentose.
 Sexual
stimulation causes release of the
secretion, which constitutes the major
portion of the preseminal fluid and probably
serves to lubricate the penile urethra.
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 The
secretion from seminal vesicles
contribute approximately 50-80 % of the
ejaculate volume, with an average volume of
2.5 ml and a pH in neutral to alkaline range.
 The
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average volume of semen: 3 ml (2-6)
Seminal vesicle: 1.5-2 ml
Prostate: 0.5 ml (15-30%)
Bulourethral and littre glands: 0.1-0.2 ml
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
The initial portion of the ejaculate contains the
highest number of spermatozoa; is rich in acid
phosphatase, citric acid, and zinc; and has a
lower pH due to prostatic fluid. The remainder
of the ejaculate largely comprises seminal
vesicle fluid, which contains a high
concentration of fructose and has a higher pH.

Normal pH of collected semen ranges from 7.2 to
7.7 and becomes more alkaline after ejaculation
and as time passes.
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
Most seminal plasma is produced by the prostate
and seminal vesicles, while the testis and
epididymis contribute less than 5% of the total
semen volume.

A low ejaculate volume reflects abnormality of
the prostate or seminal vesicles.

Fructose is produced by the seminal vesicles;
thus the absence of fructose indicates either
ejaculatory duct obstruction or seminal vesicle
aplasia/hypoplasia or cogenital bilateral absence
of the vas deferens.
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
This adds greatly to the bulk of the ejaculated semen,
and the fructose and other substances in the seminal
fluid are of considerable nutrient value for the
ejaculated sperm until one of the sperm fertilizes the
ovum.

Prostaglandins are believed to aid fertilization in two
ways:
reacting with the female cervical mucus to make it more
receptive to sperm movement
 possibly causing backward, reverse peristaltic contractions in
the uterus and fallopian tubes to move the ejaculated sperm
toward the ovaries (a few sperm reach the upper ends of the
fallopian tubes within 5 minutes).
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•
A slightly alkaline characteristic of the prostatic
fluid may be quite important for successful
fertilization of the ovum, because the fluid of
the vas deferens is relatively acidic owing to the
presence of citric acid and metabolic end
products of the sperm and, consequently, helps
to inhibit sperm fertility.
•
Also, the vaginal secretions of the female are
acidic (pH of 3.5 to 4.0). Sperm do not become
optimally motile until the pH of the surrounding
fluids rises to about 6.0 to 6.5.
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 Approximately
10% of infertile men have
blockages in the genital tract causing
absence of sperm in the semen.
 There
are four major groups of causes of
male genital tract blockages:
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disorders of development of the epididymis, vas
and seminal vesicles,
post inflammatory epididymal obstructions
(especially from gonorrhea),
vasal obstructions (vasectomy)
ejaculatory duct obstructions.
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A
20- 30% pregnancy rate can be expected
from surgical treatment in which the
obstruction is removed endoscopically, and
70% of men who undergo the procedure will
achieve a significant improvement in semen
quality.
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 Examination
of the prostate gland is by
rectal examination preferentially with the
man in the knee-elbow position.
 The
seminal vesicles are not normally
palpable. If they are palpable and/or painful
upon pressure this usually indicates
inflammation. In general, seminal vesiculitis
is accompanied by prostatitis.
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 Male
accessory gland infection (MAGI) is a
general
denominator
for
infection/inflammation of the prostate
glands, seminal vesicles, and/or epididymis.
 MAGI
may result from infection by sexually
transmitted pathogens (e.g., Chlamydia
trachomatis) or, more commonly, trivial
urinary pathogens such as E. coli, Proteus
species, enterococci, or Pseudomonas
species.
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 Include:
prostatitis,
epididimytis, urethritis
 Potentially
infertility
orchitis,
curable cause of
male
 Controversy:
Are these disease have a
negative effect on sperm quality and
male infertility
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 Depending
on the severity and the duration
of the disease and on the site of infection,
the effects on sperm quality and fertility are
largely variable.
 The
prevalence of MAGI among infertile men
is different (In Europe and in North America
8–10%).
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Urethritis
Epididymitis
Prostatovesiculitis
Silent inflammation
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Gonorrhea
Chlamydia Trichomatis
Mycoplasma spp.
Ureaplasma Urealyticum
5- E. Coli,
6- Proteus species,
7- Enterococci,
8- Pseudomonas species.
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1- Direct damage
2- Inflammation
3- Increase ROS production
4-Obstruction of seminal ducts
5- Antibody formation
6- Ejaculatory dysfunction
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
The effects of MAGI on the fertilizing capacity of
spermatozoa :
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decreased ejaculate volume
increased viscosity
abnormal biochemical composition of the seminal
fluid,
poor sperm motility,
low sperm concentration
high concentration of ROS, diminished production of
antioxidants by the epididymides damage the sperm
membrane with decreased acrosomal reactivity and
poor capacity to fuse with the oocyte membrane and
cause DNA damage.
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 Semen
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analysis may reveal:
subnormal ejaculate volume,
increased viscosity,
alkaline pH,
low concentration of citric acid and of other markers of
prostate function
below normal alpha-glucosidase activity in case of
epididymal damage.
poor sperm motility,
low sperm count,
poor sperm morphology:
high number of round cells.
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 The
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diagnosis of MAGI is based on:
medical history,
the physical examination,
echography
cytological and bacteriological analysis of urine
and blood.
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 MAGI
should be treated for reasons of ‘‘good
medical practice,’’ but the effects of
treatment on sperm quality and fertility are
limited.
 Indeed,
in the majority of cases, the function
of the accessory sex glands is irreversibly
damaged.
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
Male accessory gland infection has different
deleterious effects on fertility, depending on the
site that is affected.

Antibiotic treatment has little advantage for
fertility, but is indicated for reasons of good
medical practice if signs and symptoms of actual
infection are found.

Complementary prescription of a specific
combination of natural antioxidants and antiinflammatory substances can help to correct
some of the damage to spermatozoa caused by
MAGI.
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