Chapter The reproductive system Physiologic Concepts Spermatogenesis Spermatogenesis the formation of sperm begins during puberty and continues throughout the lifetime of a male Spermatogenesis ID: 336957
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Slide1
16 Chapter
The reproductive systemSlide2
Physiologic Concepts
Spermatogenesis
Spermatogenesis (the formation of sperm)
begins
during puberty and continues throughout the lifetime of a male.
Spermatogenesis
requires approximately 2 months.
From
each primary spermatocyte, four viable sperm
are
produced.
Spermatogenesis
occurs in the seminiferous tubule under the control of two pituitary
hormones:
follicle-stimulating hormone (FSH) and
luteinizing
hormone (LH)
and the
sex hormones, primarily testosterone.Slide3
TestesSlide4
Follicle-Stimulating Hormone
FSH
is a
hormone
released from the anterior pituitary in response to
gonadotropin-releasing
hormone (
GnRH
) .
The
final effect of FSH is to cause proliferation and differentiation of the immature sperm.
Luteinizing Hormone
LH is the
2nd hormone
released
in
response to stimulation by
GnRH
.
LH
stimulates the synthesis of the steroid hormone testosterone. Slide5
Stimuli Controlling
GnRH
Release
GnRH
is released in small pulses throughout the day, resulting in relatively constant daily levels
.
Increases or decreases in
GnRH
release may occur seasonally and with different physical and psychological conditions such as anxiety or depression.
Changes
in the secretion of
GnRH
may affect sperm formation by affecting LH and FSH and may alter libido.Slide6
The Menstrual Cycle
It is
the cyclic maturation and release of an ovum.
It
involves the growth of a follicle, ovulation of the ovum, and characteristic changes in the endometrial lining of the uterus.
Ovulation
On approximately day 12 of the menstrual cycle, there is a dramatic rise (6- to 10-fold) in the release of LH from the anterior pituitary.
This
rise is called a
preovulatory
LH surge.
FSH
increases to a lesser degree.
Rising
LH levels initiate a profound, final growth of the follicle, and then rupture, releasing the ovum into the abdominal cavity. Slide7
Phases of Menstrual cycleSlide8
Hormonal changes during menstrual cycle.Slide9
Female Secondary Sexual Characteristics
They are
under the control of estrogen and to a lesser extent
progesterone.
The
female secondary sexual characteristics include:
Fully developed breasts.
The female pattern distribution of pubic
hair.
Bone
growth and closure of the epiphyseal plates.Slide10
Puberty
Puberty
is the beginning of sexual maturation. Puberty typically occurs at a younger age in girls
(8
and
14) than boys (10
and
16)
years of age.
The
menstrual cycle is the
peak
of puberty in girls.
In
boys, puberty culminates in the ability to ejaculate mature sperm.
Menopause
Menopause is
as
a lack of menstrual cycles for the previous 12 months.
It
occurs in a woman when her ovaries no longer respond to LH and FSH with estrogen and progesterone production, and no longer release an ovumSlide11
Pathophysiologic Concepts
Infertility
Infertility is the inability or reduced ability to produce offspring
.
Infertility in a couple may result from female factors (40 to 50%), male factors (30 to 40%), or
both (20
%).
Infertility may
occur from the start of the relationship (primary infertility) or after the couple has already produced one or more offspring (secondary infertility).Slide12
Female Factors
Female
factors
include:
problems with follicular growth,
anovulation
(failure to ovulate),
or
ovulatory
irregularities.
Optimal
fertility in women lasts to about 30 years of age and then begins to fall sharply with increasing frequency as a woman ages.
Blockage
of the fallopian tubes following pelvic infection or the presence of uterine abnormalities that prevent implantation may be involved.
Immune
responses may destroy the implanted embryo if the woman is either
hyperimmune
to the embryo or fails to develop tolerance to it.
Miscarriages
later in gestation may occur if the placenta is poorly placed or poorly perfused with blood, or if the cervix cannot support the weight of a growing fetus.Slide13
Treatment of female infertility
Treatment
is
specific to the cause.
Drugs
to induce ovulation or superovulation
may
be administered.
Harvesting
of eggs from the woman for in vitro fertilization (outside of the body) may be attempted.
Eggs
fertilized outside the body may be implanted into the fallopian tube or uterus. Slide14
Male Factors
Male
factors
may include
defects in spermatogenesis that result
in:
deformed sperm or
sperm
too few in number to allow for successful penetration of the ovum.
Sperm
motility (movement) may be impaired as well. Slide15
Male Factors
Causes:
Infection
and scarring of the testicles, epididymis, vas deferens, or urethra.
Systemic
infections, such as mumps, may cause swelling of the testicles and destruction of the seminiferous
tubules.
Obstruction
of the blood vessels supplying the testes can cause hypoxia and a failure of the sperm to develop or survive.
Autoantibodies
produced against sperm may reduce sperm number and quality.
Exposure
of the testicles to high temperature may reduce spermatogenesis.Slide16
Treatment of male factor infertility
Treatment
is
specific to the cause.
For
example, for a man with a low sperm count, sperm may be obtained
and
then introduced artificially into his female partner after techniques to increase the concentration of the highest-quality sperm have been performed.
This
process is called
artificial insemination
. Slide17
Pathophysiologic Concepts
Gynecomastia
Gynecomastia
is the enlargement of breast tissue in males.
It
can result from excess production of estrogen in the male or the liver's inability to break down normal male estrogen
secretions.
It
is frequently seen during early puberty in some males and may be a normal development or may be related to excess body weight or a hormonal imbalance.Slide18
Pathophysiologic
Dysmenorrhea
Is
painful menstruation that occurs without evidence of pelvic infection or disease.
It
is usually caused by excessive release of a
specific prostaglandin (
F2 alpha
),
from the uterine endometrial cells.
Which stimulates
myometrial
smooth muscle contraction and uterine blood vessel constriction.
It
worsens the uterine hypoxia normally associated with
menstruation significant
pain.
NSAIDs
(
inhibit
prostaglandin
production)
can effectively reduce cramping. Prostaglandin inhibitors should be used at the first sign of pain or at the first sign of menstrual flow. Because forceful menstrual cramping may contribute to the development of endometriosis (painful growth of uterine tissue outside of the uterus),
Complaints
of dysmenorrhea should always be taken seriously, and attempts should be made to reduce its incidence.Slide19
Pathophysiologic
Amenorrhea
Is
the absence of a menstrual cycle.
It
is
considered:
primary if a woman has never had a menstrual cycle
or
secondary
if she has had menstrual cycles in the past, but no longer.
Amenorrhea
exists naturally before puberty (primary amenorrhea) and after menopause (secondary amenorrhea
).
It
also occurs during pregnancy, for a few to several weeks after delivery of an infant, and may occur during lactation.
Emotional
disturbances and physical stress may also cause amenorrhea.
Endocrine
disorders,
affecting ovaries
, pituitary, thyroid, or adrenal glands, can cause amenorrhea, both primary and secondary.Slide20
Conditions of Disease or Injury
Cryptorchidism
It
is the failure of one or both testicles to descend into the scrotum of a male infant.
Cryptorchidism
is present at birth and is especially common in premature infants.
Mostly
the testes will descend on their own within the first year of birth. If
not,
the testes will remain at a higher temperature
which
may affect sperm quantity and quality, leading to infertility later in life.
However, male
sexual function and secondary sexual characteristics are normal. Slide21
Cryptorchidism
Clinical Manifestations
One or both testes will not be palpable in the scrotum at birth.
Diagnostic Tools
Physical examination is used to diagnose the condition. Ultrasound or other imaging techniques may be used.
Complications
Infertility in the adult may result if descent does not occur.
Increased risk of testicular cancer exists in individuals with cryptorchidism, even after surgical repair.Slide22
Cryptorchidism
Treatment
Most cases of cryptorchidism will reverse spontaneously within 1 year. If not occur, treatment with
hCG
may stimulate descent.
If
hormonal therapy is ineffective, surgery is
required.
Surgery should be performed by 2 years of age.Slide23
Varicocele
An
abnormal dilation of a vein in the spermatic cord
.
A
sudden occurrence of a
varicocele
in
older men
may indicate an advanced renal tumor.
Clinical Manifestations
It may be
asymptomatic or associated with a slight feeling of discomfort and testicular heaviness.
Tortuous, dilated veins may be palpable.
Diagnostic Tools
Physical examination is used to diagnose the condition.
Ultrasound
may be used.
Complications
Poor blood flow to the testes may cause infertility.
Treatment
A support garment for the testicles is worn to relieve discomfort.
To maintain fertility, surgical ligation of the vein may be performed.Slide24
Hydrocele
I
s
the collection of a plasma filtrate in the scrotum, outside the
testes, that results
in scrotal swelling
and therefore testicular ischemia.
A hydrocele may
be:
a congenital problem or
Acquired;
trauma to the genitals.
A
testicular tumor may cause formation of a hydrocele
.
Idiopathic development may also occur.
Clinical Manifestations
A hydrocele may be asymptomatic or associated with palpable or visible swelling and discomfort.
Diagnostic Tools
P
hysical
examination,
augmented by US.
Visual
inspection using a light focused on the testicle may be able to identify fluid.
Treatment
Identification of the cause and drainage of the fluid.Slide25
Pelvic Inflammatory Disease
PID
is the infectious inflammation of any of the organs of the upper genital tract in women,
including:
uterus, fallopian tubes (
salpingitis
), or ovaries (
oophoritis
).
The
infectious agent is usually bacterial and is often acquired during sexual intercourse.
A
variety of
MOs may include
N.
gonorrhoeae
,
C
. trachomatis, and Escherichia coli
.
In severe cases, the entire peritoneal cavity may be affected.
Clinical Manifestations
Although occasionally a woman will be asymptomatic, she usually presents with a high fever and severe bilateral abdominal pain.
Bleeding between periods may occur.
Abdominal pain worsens with intercourse and physical activity.Slide26
Pelvic Inflammatory Disease
Diagnostic Tools
Palpating or moving the cervix during an internal pelvic examination is very painful.
Purulent discharge at the external
os
may be apparent on inspection.
Culture of the cervical discharge may indicate the infecting microorganism.
WBCs and ESR are
usually elevated.
Visualization of the inflamed pelvis by laparoscopy, the insertion of a
fiberoptic
probe, can be used to confirm the diagnosis of PID.Slide27
Pelvic Inflammatory Disease
Complications
PID may lead to scarring and adhesions of the uterus or fallopian tubes, predisposing a woman to
infertility; risk
of a subsequent ectopic pregnancy.
In
an ectopic pregnancy, the embryo implants and grows at a site other than the uterus, usually the fallopian tube.
Rupture
of the fallopian tube may occur, leading to internal hemorrhage and maternal death.
Approximately 5% to 10% of women with PID die, usually from septic shock.Slide28
Pelvic Inflammatory Diseases
Treatment
AB therapy at home or in the hospital is required.
Avoidance of sexual intercourse until the inflammation has subsided will allow healing to occur and will reduce the risk of repeated infection.
Education on the use of barrier methods of contraception (condom, diaphragm with foam or jelly) to prevent future occurrences of sexually transmitted disease is important.
Birth control pills may reduce PID by increasing the production of cervical mucus, but do not replace the need for a condom.
The sexual partner(s) of an affected woman should be evaluated for infection and, if necessary, treated with antibiotics.
Appendicitis must be ruled out as the cause of abdominal pain.Slide29
Endometriosis
Endometriosis is the presence of uterine endometrial cells outside the uterus, anywhere in the pelvic or abdominal region.
The endometrial cells respond to estrogen and progesterone with proliferation, secretion, and bleeding during the menstrual cycle.
This can cause inflammation and severe pain. The inflammation may lead to scarring of pelvic or abdominal organs and infertilitySlide30
Clinical Manifestations
Menstrual cramping and pain, ranging from mild to severe, before and/or during menstruation is the most common symptom of endometriosis.
Changes in bowel movements (diarrhea or constipation) may occur around the time of menstruation.
Pain with intercourse (
dyspareunia
) or during defecation (if rectal tissue is involved).
The pain is usually worse during menstruation, but in severe cases pain may be constant.Slide31
Endometriosis
Diagnostic Tools
Visualization of the peritoneal cavity using laparoscopic techniques can diagnose endometriosis and assign a stage to the disease.
Complications
Infertility is a common (30% to 40%) complication of endometriosis. Endometriosis may cause infertility by causing scarring and obstruction of the fallopian tubes or by initiating a maintained state of inflammation.
Hormonal disturbances may occur.
Emotional distress, family and marital problems, especially if infertility is a concern.Slide32
Cancer of the Female Reproductive Tract
Cancer of the female reproductive tract may develop in the vagina, uterus, or ovaries.
Vaginal Cancer
usually occurring in women older than 60 years of age.
The vaginal
squamous
cells are most often involved.
Frequently, the cancer is a secondary metastasis.
Uterine Cancer
Uterine cancer
includes cancer of the cervix and
endometrium
.
Cervical cancer
is often a result of STD of the cervix caused by certain strains of the human
papillomavirus
(HPV).
Cervical cancer is most common in women who have had multiple sexual partners.
The premalignant changes(dysplasia), can be identified and staged during
cytologic
studies of a cervical smearSlide33
Cancer of the Female Reproductive Tract
Uterine endometrial cancer
is the most common female reproductive cancer and is usually an
adenocarcinoma
(from the epithelial cells).
Endometrial cancer is related to lifetime exposure to estrogen and typically presents in postmenopausal women.
Ovarian Cancer
Although relatively rare, ovarian cancer causes death more often than any other female reproductive cancer. Slide34
Clinical Manifestations
Vaginal cancer
may be asymptomatic or associated with bleeding, discharge, or pain.
Cervical cancer
may be asymptomatic or associated with bleeding after intercourse or spotting between menstrual periods. A vaginal discharge with odor may be present.
Endometrial cancer
may be asymptomatic or associated with abnormal bleeding.
Ovarian cancer
is usually asymptomatic until the disease is advanced. Late symptoms include abdominal swelling and pain.
Gastrointestinal obstruction may cause vomiting, constipation, or small-volume diarrhea.Slide35
Diagnostic Tools
The Pap smear
Direct
cytologic
sampling of the vagina and
endometrium
Ovarian cancer can be identified by use of MRI or vaginal ultrasound. The ovaries may be palpable.
.
Increased level of an ovarian tumor cell antigen, CA125, in a symptomatic woman or a woman with a family history of ovarian or breast cancer can be an early indication of disease.
Complications
Death may occur with any of the reproductive cancers. Survival rates are highest (75 to 95%) with endometrial cancer and lowest (25 to 30%) with ovarian cancer. Early detection can improve survival rate significantly, especially for cervical cancer, which has a survival rate near 100% if identified while still in situ (before it has spread).