Transcript Diapositiva 1 - Holy Family Catholic Regional Division No. 37

Human Reproduction and
Development
 Anatomy of the Male and Female
Reproductive Systems
 Gamete Formation
 Hormonal Control of Reproduction
 Conception, Pregnancy,
Development, Birth
Male Anatomy
• External genitalia
– Penis and Scrotum
• Internal Reproductive Organs
– Pair of gonads
• Produce gametes (sperm cells)
• Produce hormones
– Accessory glands
• Secret products essential to sperm
movement
– Set of ducts
• Carry sperm and glandular secretions.
Male Anatomy
• Penis
– Composed of 3 cylinders of spongy tissue.
– During sexual arousal, tissue fills with blood
from the arteries
• The increasing pressure seals off the veins that
drain the penis
– Result = penis engorges with blood = erection
– The tip (Glans) is covered by a fold of skin
called the foreskin, which may be removed by
circumcision
• A tradition with religious roots.
• No verifiable health or hygienic advantage.
Male Anatomy
• Scrotum
– Sac which contains testes
– Regulates temperature of testes by
contraction of cremaster muscle.
• Cold = contracts
– Brings testes close to body to warm up.
• Warm = relaxes
• Goal = keep testes 3o below normal body
temperature.
Male Anatomy
• Testes
– Stored in scrotum
• Before birth, testes develop in the abdomen and then migrate
down a canal into scrotum around the time of birth.
– Sperm producing organ
• Made in tightly coiled tubes called seminiferous tubules
inside testes
• Sperm produced is not fully mature when it leaves testis (not
motile yet)
– Source of male hormone testosterone
• Made by interstitial cells scattered between the seminiferous
tubules
– Deposits sperm into epididymis
10
Male Anatomy
• Epididymis
– Coiled tubes
– About 6 meters long!!
– Posterior to the testis
– Stores sperm
– Site of further sperm maturation
• Gains motility
– Contracts during ejaculation, expelling sperm
into vas deferens
– Sperm can be store here for months
• If not ejaculated, will eventually be phagocytized
Male Anatomy
• Vas Deferens
– Muscular tubes that carry sperm from
epididymis to ejaculatory duct (and eventually
the urethra)
• peristalsis
– Urethra drains both the excretory system and
the reproductive system
• Not the case in females
Male Anatomy
• Ejaculatory Duct
– Connects seminal vesicle to urethra
– Passes through prostate gland
Male Anatomy
• Seminal Vesicle
– Lies below and behind bladder
– Secretes thick, clear fluid into ejaculatory duct
•
•
•
•
60% volume of semen (the fluid that is ejaculated)
Alkaline – to neutralize acidic pH of vagina
Fructose – used for energy by sperm
Prostaglandins – chemical messengers which,
once in female, stimulate uterine peristalsis to help
move semen up the uterus
• Proteins – cause semen to coagulate after it is
deposited in the female, making it easier for the
uterine contractions to move the semen
Male Anatomy
• Prostate Gland
– Doughnut shaped gland which surrounds
urethra
– Secretes thin milky fluid into urethra
• 20% of seminal volume
• Liquefy the semen – prevents sperm from
clumping together
• Alkaline – continues to neutralize acid from
residual urine in urethra and natural acidity of
vagina
Male Anatomy
• Cowper’s Gland (Bulbourethral Gland)
– Pair of small glands along urethra, below the
prostate
– Secrete viscous fluid before emission of
sperm & semen
• Thought to lubricate penis and vagina
– Released before ejaculation
• Fluid does contain some sperm
• One factor in the high failure rate of the
“withdrawal method” of birth control.
Male Anatomy
• Vasectomy
– Incision through scrotum
– Cut and tie off vas deferens
– Sperm is still produced but can’t get out
– Phagocytized
Male Anatomy Review
•
Passageway from testes to
outside
1. Multiple seminiferous tubules
•
site of spermatogenesis
2. Single tubed epididymis
3. Vas deferens
4. Seminal vesicle
5. Ejaculatory duct
6. Urethra
Fun Facts
•
For Your Information
– Volume of ejaculation = 2.75 ml
– pH = 7.2 – 7.6
– 50 – 150 million sperm per ml.
– Only a few sperm reach the egg
– Average sperm count has decreased from 113
million/ml to 66 million/ml in past 40 years.
– Infertility = <20 million/ml
• Factors leading to infertility are environmental
toxins, estrogens in meat, radiation, pesticides,
marijuana, alcohol
Labelling Diagram
1.
2.
3.
4.
5.
6.
7.
Pubic Bone
Seminal Vesicles
Rectum
Prostate Gland
Cowper’s Gland
Anus
Vas Deferens
(sperm duct)
8. Epididymis
9. Testes
10.Urethra
11.Penis
12.Scrotum
13.Head of Penis
(Glans)
14.Foreskin
15.Bladder
Hormonal Control
• Male Reproductive System Control
– Testosterone
• Primary Function
– Stimulate spermatogenesis
• Secondary Function
–
–
–
–
–
–
–
Maturation of testes and penis
Sex drive
Facial hair
Body hair
Deeper voice
Increased muscle strength
Body oil secretion -- acne
Hormonal Control
•
Hypothalamus releases
1. Gonadotropin-Releasing Hormone (GnRH)
• Stimulates pituitary to release LH & FSH
•
Pituitary releases
1. Follicle-Stimulating Hormone (FSH)
• Stimulates spermatogenesis by seminiferous
tubules
2. Luteinizing hormone (LH)
• Stimulates testosterone production by interstitial
cells
• Indirectly stimulates spermatogenesis because
testosterone is required for sperm production.
Hormonal Control
• LH, FSH, and GnRH concentrations in the
blood are controlled by negative feedback
systems
Testosterone production
Spermatogenesis
Testosterone production
Spermatogenesis
Hormonal Control
Hormonal Control
Female Anatomy
• External genitalia
- Two sets of labia that surround the clitoris
and vaginal opening
• Internal Reproductive Organs
- A pair of gonads (ovaries)
- A system of ducts and chambers to
- Conduct the gametes
- House the embryo and fetus
Internal Organs
Internal Organs
Female Anatomy
• Ovaries
– Lie in abdomen, below most of the
digestive system
– Enclosed in a tough protective capsule
– Produces eggs (follicles)
– Produces female sex hormones
1. Estrogen
2. Progesterone
Female Anatomy
Female Anatomy
•
Follicles
– Consists of one egg cell surrounded by
layers of follicle cells.
•
Nourish and protect the developing egg cell
– All of the 400,000 follicles a woman will ever
have are present at birth.
•
•
Only a few hundred will be released during a
woman’s reproductive years
One (very rarely 2 or more) follicle matures and
releases its egg during each menstrual cycle
Female Anatomy
•
Follicles
– Follicle cells release the primary female sex
hormone… estrogen.
•
•
Secondary sex characteristics, wider hips, more body fat,
Necessary for breast development
– At ovulation, the egg “explodes” out of the
follicle leaving behind the follicular tissue
•
•
This grows into a solid mass called a Corpus Luteum
– Secretes progesterone (necessary for pregnancy)
If fertilization does not occur, the corpus luteum
disintegrates and a new follicle matures the next month.
Female Anatomy
•
Oviduct
–
–
–
Fallopian tube
Conducts eggs to the uterus
Fertilization occurs here
•
–
–
If embryo grows here = ectopic pregnancy
The ovary and oviduct don’t actually touch.
The egg is released into the abdominal cavity and is
“sucked” into the oviduct.
• Oviduct has fingers called “fimbrae” and hairs
called “cilia” that vibrate and sweep the egg into
the tube by swishing body fluids towards itself
• These cilia also help move the egg towards the
uterus
Female Anatomy
Female Anatomy
•
Uterus (womb)
–
–
–
–
Houses and nurtures the developing fetus
Oviducts enter at the top
Cervix (opening) at the bottom
The lining is called the endometrium
•
•
•
•
Richly supplied with blood vessels
Varies in thickness depending on the stage of the
menstrual cycle
Controlled by hormones
2 Layers
– Basal layer = stable, does not change thickness
– Functional layer = changes thickness with menstruation
Female Anatomy
Female Anatomy
•
Vagina
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–
–
–
–
–
Birth canal
Average = 7.5 cm in length
pH = 4-5
Upper end closes at cervix
Receives penis during sexual intercourse
Elastic to facilitate sexual intercourse and
birth
Female Anatomy
Gametogenesis
1.
2.
3.
4.
The walls of the seminiferous
tubules consist of diploid
spermatogonia, stem cells
that are the precursors of
sperm.
divide by mitosis to produce
more spermatogonia
The Meiosis of each
spermatocyte produces 4
haploid spermatids.
These then differentiate into
sperm, losing most of their
cytoplasm and gaining
motility in the process.
In epididymis


Sperm nourished by sertoli
cells (in seminiferous tubules)
Whole process takes 70 days
Gametogenesis
1.
2.
3.
4.
5.
6.
Takes place in ovaries
Primary Oogonium develop
into oocytes before birth
Oocytes complete maturation
one at a time & once a month
during reproductive years
Primary oocyte grows larger
and begins meiosis
Forms a secondary oocyte
and first polar body
After fertilization, secondary
oocyte completes meiosis and
become 1 egg and second
polar body.
Hormonal Control
•Hypothalamus - produces releasing GnRH
•Anterior Pituitary – secrete gonadotropic hormones.
–FSH - follicle stimulating hormone.
–LH - luteinizing hormone.
•Ovaries - secrete the female sex hormones.
–Estrogen –thickening of uterine lining
–Progesterone – matures/maintains uterine lining
Hormonal Control
• FSH is released from AP
–Start the ripening of ovum within follicle
• Estrogen is produced by follicle
–Development of endometrium for possible
pregnancy
–Feedback to hypothalamus to inhibit FSH
and release LH
Hormonal Control
• LH surge on day 14
–Stimulates ovulation
–Conversion of follicle into corpus
luteum
• Progesterone production
– Continued development of
endometrium
– Feedback to inhibit release of LH
Hormonal Control
•If no fertilization
– Degeneration of corpus luteum
– Drop in hormone level
The 4 Phases of Menstruation
Female Anatomy
• sdfsdfsdf
Menstruation
1. Flow Phase (Menstrual Phase)
– Start of bleeding marks Day 1 of
phase
– Shedding of the endometrium
(uterine lining)
– Average = 4-5 days
• Sometimes up to 8 days
– Occurs due to low hormone levels
Female Anatomy
• sdfsdfsdf
1
Menstruation
2. Follicular Phase
– Occurs during day 6-13
– Period of repair and thickening of
endometrium.
Female Anatomy
• sdfsdfsdf
Menstruation
2. Follicular Phase
– Occurs during day 6-13
– Period of repair and thickening of
endometrium.
– FSH from the pituitary promotes follicle
development in the ovary.
Female Anatomy
• sdfsdfsdf
Menstruation
2. Follicular Phase
– Occurs during day 6-13
– Period of repair and thickening of endometrium.
WHY??
– FSH from the pituitary promotes follicle development
in the ovary.
– As follicle develops it produces estrogen,
• thickening of the uterine lining
• LH production increase
• FSH production decrease
Menstruation
FSH
Decrease
Menstruation
3. Ovulation Phase
– LH causes ovulation to occur on
day 14.
• Secondary oocyte is released
from the follicle/ovary.
Female Anatomy
• sdfsdfsdf
Menstruation
4. Luteal Phase
– Final preparation of endometrium to
receive the fertilized ovum
– LH stimulates development of the
Corpus Luteum.
• causes progesterone levels to
increase.
Menstruation
Menstruation
4. Luteal Phase
– Final preparation of endometrium to receive
the fertilized ovum
– LH stimulates development of the Corpus
Luteum.
• causes progesterone levels to increase.
– Estrogen and progesterone inhibit GnRH,
thereby decreasing LH and FSH levels.
– This low level of hormones initiates the flow
phase.
Menstruation
Menstruation
Menstruation
Menopause
• The end of a woman’s reproductive years
• Between ages of 45 – 55
• Ovaries no longer respond to FSH & LH from AP
– Ovaries do not produce estrogen or
progesterone
• Marked by circulatory irregularities (hot flashes),
dizziness, insomnia, sleepiness, depression
• Hormone replacement therapy may help.
Human Reproduction and
Development
 Fertilization
 Pregnancy
 Development
 Birth
Human Reproduction and
Development
Sperm
Human Reproduction and
Development
3 Steps of Fertilization
1. Capacitating
– Acidic environment of the
female reproductive tract
causes small pores to open in
the acrosome (“enzymeloaded” head) of the sperm
3 Steps of Fertilization
3 Steps of Fertilization
1. Capacitating
– Acidic environment of the
female reproductive tract
causes small pores to open in
the acrosome (“enzymeloaded” head) of the sperm
2. Acrosomal reaction
– Enzymes released from acrosome
digest the outer membrane
surrounding the egg cell
3 Steps of Fertilization
3. Fertilization
– A single sperm cell fuses with
the plasma membrane of ovum
– Head passes into the
cytoplasm
– Electrochemical reaction in egg
• Makes membrane
impermeable to other sperm
Fertilization
•
Fertilization must occur within a
very short window of opportunity.
– Egg is only fertile for 12-24
hours
– Sperm can survive up to 5
days in the body
– Sex (copulation) must occur no
more than 5 days before or 1
day after ovulation
Pregnancy
• If pregnancy is established, menstruation does
not occur.
• Fertilized egg is called a zygote.
– Once cell division brings the total cell count
to around 8, it is called a blastocyst.
• Takes 3-5 days for blastocyst to travel through
oviduct to uterus.
• Blastocyst must implant into endometrium
– Occurs 2-4 days after reaching the uterus
Fertilization
• If pregnancy is established, menstruation does
not occur.
• Fertilized egg is called a zygote.
– Once cell division brings the total cell count
to around 8, it is called a blastocyst.
• Takes 3-5 days for blastocyst to travel through
oviduct to uterus.
• Blastocyst must implant into endometrium
– Occurs 2-4 days after reaching the uterus
Fertilization
• If pregnancy is established, menstruation does
not occur.
• Fertilized egg is called a zygote.
– Once cell division brings the total cell count
to around 8, it is called a blastocyst.
• Takes 3-5 days for blastocyst to travel through
oviduct to uterus.
• Blastocyst must implant into endometrium
– Occurs 2-4 days after reaching the uterus
Fertilization
• If pregnancy is established, menstruation does
not occur.
• Fertilized egg is called a zygote.
– Once cell division brings the total cell count
to around 8, it is called a blastocyst.
• Takes 3-5 days for blastocyst to travel through
oviduct to uterus.
• Blastocyst must implant into endometrium
– Occurs 2-4 days after reaching the uterus
Pregnancy
• During implantation, the blastocyst produces a
hormone called HCG
– Human chorionic gonadotropin
– Prevents degeneration of corpus luteum
– Stimulates corpus luteum to increase
progesterone secretion
• Maintains uterine lining
• Prevents contractions
– Pregnancy test detects HCG in the urine of
women.
• “Turns the stick blue”
Pregnancy
• Tissue grows out from the embryo and
mingles with endometrium to form placenta
– A disc-shaped organ
– Size of dinner plate
– Weighs less than 1 kg.
– Contains maternal & fetal blood vessels
• NO mixing of maternal and fetal blood!!
– Diffusion of gasses, nutrients, & wastes
– Continues production of HCG, estrogen,
progesterone
• Maintains endometrium
• Corpus luteum not needed – dissolves
Pregnancy
• Progesterone & estrogen have a
negative feedback effect on the
hypothalamus
– No secretion of FSH
– No secretion of LH
– No new follicles mature
• Embryo remains firmly attached to
placenta by umbilical cord.
Pregnancy
• Umbilical cord
–Contains:
• 2 fetal arteries
–Fetus to placenta
• One fetal vein
–Placenta to fetus
Pregnancy
Childbirth
•
•
Also called parturition
38 – 42 weeks from conception
– Average = 40 weeks
• Three stages of childbirth
1. Labour
2. Delivery
3. Afterbirth
Childbirth
1. Labour
– Involuntary
– Rhythmic contractions of the uterus
– Causes cervix to open
• Diameter = 10 cm
2. Delivery
– Involuntary uterine contractions
– Conscious abdominal contractions
– Mother forces baby out through cervix and
vagina
Childbirth
3. Afterbirth
– Immediately after delivery
– Blood vessels in placenta
contract
– Placenta separates from
uterine wall
– Expelled by muscle
contractions
Childbirth
• Why??
– Nobody totally knows.
– Baby plays some role in the timing.
– Progesterone decreases
• Allows uterus to contract
– Oxytocin from posterior pituitary
• Stimulates stronger uterine contractions
– Relaxin
• produced by placenta
• Causes ligaments of pelvis to loosen
• Larger passageway for baby
Lactation
• During pregnancy, high levels of estrogen and
progesterone prepare the breasts for milk
production
– Each breast has about 20 milk glands
– Connect to the nipple by ducts
– Breast enlarges during pregnancy in
preparation for lactation
• Expulsion of the placenta causes the mother's
pituitary to secrete prolactin,
– Initiates lactation
Lactation
• Prolactin inhibits the release of LH
– menstrual cycle is suppressed in
nursing mothers
• The high estrogen and
progesterone levels during
pregnancy are thought to inhibit
release of prolactin
Lactation
• The first fluid formed by the mammary glands
is colostrum,
– Thick
– contains lactose and milk proteins,
– lacks fat
– after a few days, milk is produced
• Oxytocin is released from hypothalamus when
infant suckles
– Causes milk to be released from mammary
glands
Fetal Development
• A blastocyst
– embeds in the uterine wall
– Consists of cells of the future
embryo
– Surrounded by a sphere of cells
• Embryonic membrane (extraembryonic membrane)
• Support the developing
embryo
Fetal Development
• Amnion
– Innermost embryonic membrane
• Next to baby
• Fluid-filled sac that cushions
the baby
Fetal Development
• Chorion
–Outermost membrane
• Part of the placenta
• Secretes HCG
113
Fetal Development
• Umbilical cord
– Connection between mother
and baby
• Belly-button to placenta
– Carries baby’s blood to and
from placenta
Embryonic Development
• Placenta (review)
– A disc-shaped organ
– Size of dinner plate
– Contains maternal & fetal blood
vessels
• NO mixing of maternal and fetal
blood!!
– Diffusion of gasses, nutrients, &
wastes
– Continues production of HCG,
estrogen, progesterone
Embryonic Development
•
A blastocyst undergoes gastrulation
–
Series of cell movements and shape changes
–
Produces an embryo with 3 cellular layers
1. Ectoderm
•
Outer layer of cells
•
Will become skin and nervous system
2. Mesoderm
•
Middle layer of cells
•
Skeleton, muscles gonads, kidneys,
circulatory system
3. Endoderm
•
Inner layer of cells
•
Liver, pancreas, lungs, lining of digestive tract
Gastrulation
Human Gestation
• 1st Trimester
–From fertilization to end of
3rd month (0 – 13 weeks)
–Zygote begins cell division
as it moves down oviduct
–Becomes blastocyst and
implants in uterus
Human Gestation
• 1st Trimester
– Development of body organs
– Heart starts beating by week 4
– Week 7, testosterone begins to
be secreted if a Y-chromosome
is present
• This testosterone causes
development of testes.
Human Gestation
• 1st Trimester
– By week-8 all major structures of
the adult are present (in basic
form)
• Embryo is now called a fetus
– Embryo is most sensitive during
first trimester
• Due to rapid development
• Sensitive to radiation and
drugs
Gastrulation
Gastrulation
6
weeks
7 weeks
Gastrulation
Gastrulation
8
Weeks
8 weeks
10 Weeks
11 Weeks
11 Weeks
14
Weeks
Human Gestation
• 2nd Trimester
– Fetus grows rapidly
• To about 30 cm
– Quite active
– Hair begins to develop
– Cartilage of skeleton is
replaced by bone
18 weeks
Gastrulation
The Hand Picture
May 2, 2000
USA Today
133
An Amazing Story -- Aug.19, 1999
• Samuel Armas' tiny hand grips Dr.
Joseph P. Bruner's finger just as Bruner
finishes returning him to his mother's
womb.
• Bruner, director of fetal diagnosis and
treatment at Vanderbilt University
Medical Center (Nashville), was
performing a cutting-edge procedure on
the 21-week-old fetus.
• The procedure on Samuel took about
an hour.
134
An Amazing Story -- Aug.19, 1999
• Bruner and Samuel's parents hope the
surgery will alleviate the effects of spina
bifida, a disabling birth defect in one or
two of every 1,000 babies born.
• Because fetuses undergoing this
procedure are so young -- Samuel could
not survive outside his mother's womb -this kind of surgery is gaining attention
nationwide from the medical community
and the media.
135
An Amazing Story -- Aug.19, 1999
• During the procedure, surgeons remove
the uterus from the mother, drain the
amniotic fluid, perform surgery on the tiny
fetus, replace everything and put the
entire package back inside the mother.
• Dr. Bruner said regarding the picture,
"The baby did not reach out," Bruner
says. "The baby was anesthetized. The
baby was not aware of what was going
on."
136
An Amazing Story -- Aug.19, 1999
• Bruner says he saw the hand "sort of
pop up in the incision" on the womb,
and he "reached over and picked it up."
• Samuel, now nearly 5 months old [may
2, 2000], & is “developing normally and
hitting his monthly milestones. He
smiles often and is nearly sitting up on
his own.”
• It will take years to know how much
difference the surgery made, but Alex
Armas [father] says he's happy the
photo has been seen by millions.
137
Samuel
Armas
21 weeks
Human Gestation
• 3rd Trimester
– Rapid growth of fetus
• To about 53 cm
• 3-3.5 kg
– Fetal activity decreases
• Less room to move
– Fully mature
– Ready for birth
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Parturition
Reproductive Technologies
Birth Control
• Sterilization
– Most effective
– In males vas deferens is cut off and
sealed
• Only effects sperm content of
semen so minimal side effects
– In females tubal ligation or cutting
of the oviducts
• Disadvantages of sterilization - hard
to reverse
Birth Control
• “The pill"
– A combination of estrogen and
progesterone given for 21 days of
the 28 day cycle
– Effectively shuts down FSH and LH
production so follicles do not
develop.
– Many of the early problems have
been sorted out but side effects
possible
Birth Control
• Barrier Methods
– Diaphragms, Cervical Caps, Vaginal
Sponges, Condoms
• Condom
– fits over the penis and prevents semen
from entering the female;
• Diaphragm
– which fits over the cervix and prevents
semen from entering the uterus
• both of these methods are more reliable
when used in conjunction with a spermicidal
foam or jelly
Birth Control
• IUD
– Inter-Utarian Device
– placed in the uterus by a physician,
– prevent implantation of the
blastocyst in the endometrium.
– Best for women who have had one
pregnancy, middle to older and are
at low risk for STI’s
Birth Control
• "Natural family planning"
– Requires knowledge of the day of
ovulation
– If known, can avoid the 4 days either side
of ovulation to account for unusually long
-lived sperm or eggs.
– Women need exceptionally regular
cycles to be effective
– "Basal" body temperature measurements
(T rises at ovulation), vaginal pH
measurements (more alkaline), mucus
thickness can help determine time
ovulation.
Birth Control
• "Morning after pill“
– Most are essentially a controlled
overdose of normal birth control pills
– RU-486 now distributed by Planned
Parenthood.
– Blocks progesterone receptors causing
uterine lining to slough off taking embryo
with it.
– Many people have ethical problems with
these pills since they remove fertilized
eggs.
• i.e. after "conception" has occurred.
• “abortion pill”
Reproductive Technologies
• Ultrasound
– the use of high-frequency sound waves
to visualize the fetus
• Amniocentesis
– a long needle is used to remove a
sample of amniotic fluid from the amniotic
sac surrounding the fetus,
– fetal cells in the fluid are cultured for 2 to
4 weeks and then analyzed for
chromosomal defects and other genetic
disorders
Amniocentesis
Reproductive Technologies
• Chorionic Villi Sampling (CVS)
– a small sample of tissue is removed from the
chorion,
• the fetal part of the placenta.
– Can be performed earlier in the pregnancy than
amniocentesis
– results can be obtained within a few days
– greater risk of spontaneous abortion from CVS
than from amniocentesis
– ethical considerations: essentially all detectable
fetal disorders remain untreatable in the uterus,
and many cannot be corrected even after birth
Reproductive Technologies
• In Vitro Fertilization
– ova can be surgically removed from a
woman whose oviducts are blocked
– These are fertilized in a petri dish in a
laboratory
– The resulting embryos can than be
inserted into the woman's uterus (or into
a surrogate mother's uterus)
– Ethical considerations: post-menopausal
woman can now have children; in
surrogacy, who is the legal mother???
STIs
Crabs
Epididimitis
Genital Warts
Syphilis
Gonorrhea
STIs
• Syphilis
– caused by a spirochete bacterium.
– The first symptoms of syphilis
may go undetected because they
are very mild and disappear
spontaneously.
– The initial symptom is a chancre;
• usually a painless open sore
that usually appears on the
penis or near the mouth, anus,
or on the hands.
STIs
– may go on to more advanced
stages, including a transient
rash and, eventually, serious
involvement of the heart and
central nervous system.
– The full course of the disease
can take years.
– Penicillin remains the most
effective drug to treat people
with syphilis.
Initial Chancre on Hand
STIs
• Gonorrhea
– discharge from the vagina or penis
• “Ooooze”
– and painful or difficult urination.
– The most common and serious
complications occur in women and, these
complications include PID, ectopic
pregnancy, and infertility.
– Historically, penicillin has been used to treat
gonorrhea, but in the last decade, four types
of antibiotic resistance have emerged.
– New antibiotics or combinations of drugs
must be used to treat these penicillin
resistant strains.
STIs
• Chlamydia
– many cases involve no symptoms and
therefore infected persons may not seek
medical treatment.
– This infection is now the most common of all
bacterial STD's, with an estimated 4 to 8
million new cases occurring each year.
– In both men and women
– abnormal genital discharge
– burning with urination
– In women, untreated chlamydial infection
may lead to pelvic inflammatory disease,
• one of the most common causes of
ectopic pregnancy and infertility in
women.
STIs
– Many people with chlamydial
infection, however, have few or
no symptoms of infection.
– Once diagnosed with
chlamydial infection, a person
can be treated with antibiotics
STIs
• Genital herpes
– Affects an estimated 60 million Americans.
– Approximately 500,000 new cases of this
incurable viral infection develop annually.
– Caused by herpes simplex virus (HSV).
– painful blisters or open sores in the genital
area.
– These may be preceded by a tingling or
burning sensation in the legs, buttocks, or
genital region.
– The herpes sores usually disappear within
two to three weeks, but the virus remains in
the body for life and the lesions may recur
from time to time.
STIs
• Genital herpes
– Severe or frequently recurrent genital herpes
is treated with one of several antiviral drugs
that are available by prescription.
• These drugs help control the symptoms
but do not eliminate the herpes virus
from the body.
• Suppressive antiviral therapy can be
used to prevent occurrences and
perhaps transmission.
– Women who acquire genital herpes during
pregnancy can transmit the virus to their
babies.
– Untreated HSV infection in newborns can
result in mental retardation and death.
STIs
• AIDS (acquired immunodeficiency syndrome)
• First reported in the United States in1981.
• It is caused by the human immunodeficiency
virus (HIV),
– a virus that destroys the body's ability to fight
off infection.
• An estimated 900,000 people in the United
States are currently infected with HIV.
• People who have AIDS are very susceptible to
many life-threatening diseases (called
opportunistic infections) and to certain forms of
cancer.
• Transmission of the virus primarily occurs during
sexual activity and by sharing needles used to
inject intravenous drugs.
STIs
•
Genital warts
– Caused by human papillomavirus,
• a virus related to the virus that causes common skin
warts.
– Genital warts usually first appear as small, hard painless
bumps in the vaginal area, on the penis, or around the
anus.
– If untreated, they may grow and develop a fleshy,
cauliflower-like appearance.
– Genital warts infect an estimated 1 million Americans
each year.
– In addition to genital warts, certain high-risk types of HPV
cause cervical cancer and other genital cancers.
– Genital warts are treated with a topical drug (applied to
the skin), by freezing, or if they recur, with injections of a
type of interferon.
– If the warts are very large, they can be removed by
surgery.
STIs
• Genital herpes
– Affects an estimated 60 million Americans.
– Approximately 500,000 new cases of this
incurable viral infection develop annually.
– Caused by herpes simplex virus (HSV).
– painful blisters or open sores in the genital
area.
– These may be preceded by a tingling or
burning sensation in the legs, buttocks, or
genital region.
– The herpes sores usually disappear within
two to three weeks, but the virus remains in
the body for life and the lesions may recur
from time to time.
STIs
• Genital herpes
– Affects an estimated 60 million Americans.
– Approximately 500,000 new cases of this
incurable viral infection develop annually.
– Caused by herpes simplex virus (HSV).
– painful blisters or open sores in the genital
area.
– These may be preceded by a tingling or
burning sensation in the legs, buttocks, or
genital region.
– The herpes sores usually disappear within
two to three weeks, but the virus remains in
the body for life and the lesions may recur
from time to time.