Reproductive System, Charleigh Ochoa P. 1
Major Functions
Male
Female
Anatomy of Male Reproductive Structures
Anatomy of Female Reproductive Structures
Events of Female Hormonal Cycles
Disorders
Female Hormones
Male Hormones
Both
Form gametes
Bring gametes together
Combine genetic information through fertilization
Support development of fetus and birth of baby
Spermatogenesis
Oogenesis
Testes
Ovaries
Testosterone
Estrogens
Progesterone
Gonadotropin-releasing Hormone (GnRH)
Follicle-stimulating Hormone (FSH)
Luteinizing Hormone (LH)
Gonadotropin-releasing Hormone (GnRH)
Luteinizing Hormone (LH)
Follicle-stimulating Hormone (FSH)
Inhibin
Inhibin
sperm-producing gonads
lie within the scrotum
Ejaculatory Duct
Ductus (Vas) Deferens
Urethra
Epididymis
Prostate
Seminal glands
Scrotum
sac of skin and superficial fascia
hangs outside abdominopelvic cavity at root of penis
contains paired testes at 3º C lower than core body temp
lower temp is necessary for sperm production
divided into two compartments, one for each testis
each is surrounded by two tunics
Tunica albuginea
Tunica vaginalis
outer layer formed from peritoneum
inner layer forms fibrous capsule
divided into ~250 lobules, each containing 1-4 seminiferous tubules
site of sperm production
sperm is conveyed from STs to rete testis to efferent ductules to epididymis
Spermatic cord encloses nerve fibers, blood vessels, and lymphatics that supply testes
Testicular Cancer
Rare, but most common cancer in men age 15-35
Symptoms
painless, solid mass in testis
Treatment
90% cured by surgical removal of testis and often radiation or chemotherapy
area in which sperm mature
Penis
highly coiled
pass slowly through at rate that takes ~20 days to gain ability to swim
can be stored for several months
contracts during ejaculation, expelling sperm into ductus deferens
passes through inguinal canal to pelvic cavity
joins duct of seminal vesicle to form ejaculatory duct
smooth muscle in walls propels sperm from epididymis to urethra
conveys both urine and semen (at different times)
male copulatory organ
consists of:
root and shaft that ends in glans penis
prepuce or foreskin
60% of US males are circumcised, foreskin surgically removed
internally, made up of spongy urethra and 3 cylindrical bodies of erectile tissue, spongy network of connective tissue and smooth muscle with vascular spaces
Corpora cavernosum
Corpus spongiosum
surrounds urethra and expands to form glans and bulb of penis
paired dorsal erectile bodies
Erection
erectile tissue fills with blood, causing penis to enlarge and become rigid
contains smooth muscle that contracts during ejaculation
produces viscous alkaline seminal fluid
fructose, citric acid, coagulating enzyme (vesiculase), and prostaglandins
comprises 70% volume of semen
duct joins ductus deferens to form ejaculatory duct
encircles urethra inferior to bladder
consists of smooth muscle that contracts during ejaculation
secretes milky, slightly acidic fluid
contains citrate, enzymes, and prostate-specific antigen (PSA)
plays a role in sperm activation
enters prostatic urethra during ejaculation
makes up 1/3 of semen volume
Bulbo-urethral glands (Cowper's gland)
produce thick, clear mucus during sexual arousal
lubricate glans penis
neutralizes traces of acidic urine in urethra
Prostatitis
common reason for man to consult urologist
Prostate Cancer
Third most common cause of cancer death in males that affects 1 in 6 men in US
Digital exam screening, PSA levels can be checked by having high rate of false positives
Treated with surgery and sometimes radiation
Metastatic prostate cancer treated with drugs that block testosterone synthesis or action
Semen
milky-white mixture of sperm and accessory gland secretions
2-5 ml semen are ejaculated containing 20-150 million sperm/ml
contains fructose for ATP production, protects and activates sperm, and facilitates sperm movement
alkaline fluid neutralizes acidity of male urethra and female vagina and enhances motility
synthesized from cholesterol, transformed at some target cells
prompts spermatogenesis and targets all accessory organs
has multiple anabolic effects throughout body
process of forming male gametes in seminiferous tubules
begins at puberty ~14 years old
adult makes ~90 million sperm daily
Secondary sex characteristics
larynx enlargement causes deepening of voice
skin thickens and becomes oily
bones grow, increase in density
skeletal muscles increase in size and mass
enhanced growth of hair on chest or other areas
boosts basal metabolic rate
Appearance of pubic, axillary, and facial hair
basis of sex drive (libido)
female gonads
secrete female sex hormones
produce female gametes (ova)
progesterone
estrogen (estradiol, estrone, estriol)
located in pelvic cavity
including duct system
uterine tubes
uterus
vagina
paired structures flank the uterus, are almond shaped and about twice as large
each ovary is held in place by several ligaments
ovarian ligament: anchors ovary medially to uterus
suspensory ligament: anchors ovary laterally to pelvic wall
along with mesovarium, are part of broad ligament that supports uterine tubes, uterus, and vagina
Ovarian Follicles
tiny saclike structures embedded in cortex
contain immature egg (oocyte) encased by one or more layers of very different cells
each month a ripened follicle ejects oocyte in event called ovulation
Duct System
uterine tube system does not have direct contact with ovaries
ovulated oocyte is released into peritoneal cavity, where some oocytes never make it to tube system
Uterine Tube System
Uterus
Vagina
The Uterine Tubes
fallopian tubes or oviducts
receive ovulated oocyte and are usual site of fertilization
each tube ~10cm (4 in) long and extends from area of ovary to superior region of uterus
Infundibulum
funnel-shaped opening into the peritoneal cavity
margin contains ciliated projections call fimbriae that drape over ovary
usual site of fertilization
during ovulation, uterine tube captures oocyte
oocyte is carried along toward uterus by smooth muscle peristalsis and ciliary action
thin-walled tube 8-10cm (3-4in) in length
hollow, thick-walled, muscular organ
functions to receive, retain, and nourish fertilized ovum
Regions
Body
Fundus
Isthmus
Cervix
Cervical canal
major portion
rounded superior region
narrowed inferior region
narrow neck, or outlet; projects into vagina
communicates with:
vagina via external os
uterine body via internal os
Cervical Cancer
affects 450,000 women worldwide each year, killing half
Most common between ages 30 and 50
Risks
frequent cervical inflammation; STIs, including HPV; or multiple pregnancies
Treatment
Gardasil:three-dose vaccine; protects against HPV
Papanicolau (Pap) smear
recommended for 11 and 12 year old girls
for detection:
recommended every 3 years for ages 21-30
every 5 years for ages 30-65, but include HPV testing
Discontinue at 65, after hysterectomy, or with sexual activity
Uterine Wall
Myometrium
Endometrium
Perimetrium
outermost serous layer (visceral peritoneum)
bulky middle layer consisting of interlacing layers of smooth muscle
contracts rhythmically during child-birth
mucosal lining
simple columnar epithelium on top of a thick lamina propia
fertilized egg burrows into endometrium and resides there during development
functions as birth canal, passageway for menstrual flow, and organ of copulation
vaginal secretions are acidic in adult females
mucosa near vaginal orifice forms incomplete partition called hymen that ruptures with intercourse
External Genitalia
Labia majora
Labia minora
Mons pubis
Vestibule
Clitoris
Perineum
fatty area overlying pubic symphysis
hair-covered, fatty skin folds
skin folds lying within labia majora
recess within labia minora
anterior to vestibule
diamond-shaped region between pubic arch and coccyx
counterpart of scrotum
counterpart of penis, body of clitoris has erectile tissue
Breast Cancer
Invasive breast cancer is most common malignancy and second most common cause of cancer death in women
13% of women will develop
Usually arises from epithelial cells of smallest ducts that eventually metastasize
Risk factors
early onset of menstruation and late menopause
no pregnancies or first pregnancy late in life
no or short periods of breast feeding
family history of breast cancer
10% due to hereditary defects, including mutations to genes BRCA1 and BRCA2
70% of women with breast cancer have no known risk factors
Greater risk of ovarian cancer as well
50% to 80% of women with these genes develop breast cancer
Diagnosis
Early detection via self-examination and mammography, a type of x-ray examination
Recommended screening every year fro age 40+
Treatment
Depends upon characteristics of lesion
radiation, chemotherapy, or surgery followed by radiation or chemotherapy
drugs for estrogen-responsive cancers
Lumpectomy: less invasive and excises cancerous lump
production of female gamete
begins in fetal period
Primary oocytes that undergo meiosis I to produce
Secondary oocytes that undergo meiosis II to produce
Oogonia (diploid stem cells) divide by mitosis to produce
Ova
At birth, female presumed to have lifetime supply of primary oocytes
Primordial follicle
Secondary follicle
Vesicular (antral) follicles (tertiary follicles)
single layer of squamous pre-granulosa cells surrounding primary oocyte
have multiple layers of granulosa cells surrounding primary oocyte
have a fluid-filled cavity called an antrum
before ovulation primary oocyte inside vesicular follicle resumes meiosis and becomes secondary oocyte
begins during fetal period and takes years
first to develop in fetus
Ovulation
each month after puberty, a select few primary oocytes are activated
caused by high hormonal levels, especially FSH
One from this group is "selected" each month to become dominant follicle
Follicle Development
Follicles and oocytes may take nearly a year to mature before ovulation can occur
Maturation phase
Phase 1
Phase 2
gonadotropin-independent pre-antral phase involves intrafollicular paracrines
antral phase stimulated by FSH and LH
Dominant follicle is selected
Primary oocyte resumes meiosis I
Stages of Development
primordial follicle becomes primary follicle
oocyte secretes glycoprotein-rich substances that forms zona pellucida that encapsulates oocyte
Secondary follicle becomes vesicular (antral) follicle
Primary follicle becomes secondary follicle
Antrum: large cavity that is formed when all fluid coalesces
distinguishes vesicular follicle from previous follicles
Antrum continues to expand with fluid isolating oocyte
isolated oocyte with its surrounding granulosa cells called corona radiata
After oocyte & corona radiata are ejected, ruptured follicle transforms into glandular structure called corpus luteum
Ovarian Cycle
monthly series of events associated with maturation of egg
Follicular phase: period of vesicular follicle growth (days 1-14)
Luteal phase: period of corpus luteum activity (days 14-28)
two consecutive phases, with ovulation ocurring midcycle between pahses
several vesicular follicles become sensitive to FSH and are stimulated to grow
FSH levels drop around middle of phase
dominant follicle outcompetes other follicles and is only one to continue on
Ovulation
in-between follicular and luteal phase
ballooning ovary wall ruptures, expelling secondary oocyte with its corona radiata into peritoneal cavity
after ovulation, ruptured follicle collapses, and sntrum fills with clotted blood
remaining cells form corpus luteum
secretes progesterone and some estrogen
Hormonal interaction during Ovarian Cycle
Negative feedback inhibits gonadotropin release
Positive feedback stimulates gonadotropin release
FSH and LH stimulate follicles to grow, mature, and secrete sex hormones
LH surge triggers ovulation and formation of the corpus luteum
GnRH stimulates FSH and LH secretion
Negative feedback inhibits LH and FSH release
The Uterine (Menstrual) Cycle
cyclic series of changes in endometrium that occur in response to fluctuating ovarian hormone levels
Three phases
Days 6-14: proliferative (preovulatory) phase
Days 15-28: secretory (postovulatory) phase
Days 1-5: menstrual phase
gonadotropin levels begin to rise
stratum functionalis detaches from uterine wall and is shed
Ovarian hormones at lowest
By day 5, growing ovarian follicles start to produce more estrogen
menstrual flow of blood and tissue lasts 3-5 days
estrogen also increases synthesis of progesterone receptors in endometrium
thins out normally thick, sticky cervical mucus to facilitate sperm passage
rising estrogen levels prompt generation of new stratum functionalis layer
ovulation occurs at end of proliferative phase on day 14
as layer thickens, glands enlarge, and spiral arteries increase in number
endometrium prepares for embryo to implant
If fertilization does not occur
phase that is most consistent in duration
endometrial cells die; and glands regress
blood vessels fragment, and functional layer sloughs off and uterine cycle starts all over again on first day of menstruation
corpus luteum degenerates toward end of secretory phase; progesterone levels fall
Effects of Estrogens and Progesterones
Estrogens
Progesterones
support rapid short-lived growth spurts at puberty
Induce secondary sex charcateristics
exert anabolic effect on female reproductive tract
Estrogen also has metabolic effects
promote oogenesis and follicle growth in ovary
works with estrogen to establish and regulate uterine cycle
promotes changes in cervical mucus
effects of placental progesterone during pregnancy
growth of breasts
increased deposits of subcutaneous fats
widening and lightening of pelvis
maintains low total blood cholesterol and high HDL levels
facilitates calcium uptake
inhibits uterine motility
helps prepare breasts for lactation
Sexually Transmitted Infections
Viral STIs
Trichomoniasis
Gonorrhea
Chlamydia
Syphilis
HPV
Genital herpes
most common bacterial STI in US
can be contracted from birth canal by newborns
responsible for 25-50% of all diagnosed cases of PID
Symptoms
Treatment
Antibiotics
urethritis
painful intercourse
irregular menses
abdominal, rectal, or testicular pain
penile and vaginal discharges
can lead to sterility
parasitic infection that is more common in women than men
easily and inexpensively treated
Symptoms
70% of women have no symptoms
30% have yellow-green vaginal discharge with strong odor
Bacterial infection of mucosae of reproductive and urinary tracts
most infections are asymptomatic
Symptoms
Females
Males
urethritis, painful urination, discharge of pus. from penis
abdominal discomfort, vaginal discharge, or abnormal uterine bleeding, and possible urethral symptoms
untreated can cause urethral constriction and inflammation of duct system
untreated can lead to pelvic inflammatory disease and sterility
Treatment
antibiotics, two antibiotic treatments required
bacterial infection transmitted sexually or congenitally
infected fetuses can be stillborn or dies shortly after birth
Infection is asymptomatic for 2-3 weeks and then painless chancre appears at site of infection
disappears within a few weeks
If untreated, secondary signs appear weeks later
Pink skin rash, fever, and joint pain can develop
appear for 3-12 weeks, then disappear
Can enter latent period, which may or may not progress to tertiary syphilis
Treatment
Penicillin
group of ~40 or more viruses is most common in US
over 50% of adults are infected during lifetime
cause of genital warts
can cause multiple cancers
Vaccination can guard against most common cancer-causing strains
recommended for boys and girls before becoming sexually active
One of most difficult human pathogens to control because most do not know they are infected
only 15% display signs of infection
Characterized by latent periods and flare ups with vesicle formation
Treatment
antiviral drugs can reduce duration and intensity of flare-ups
Puberty
period when reproductive organs grow to adult size and become functional
occurs in response to rising levels of gonadal hormones
secondary sex characteristics also appear
earliest time reproduction is possible
Menopause
has occurred when menses have ceased for an entire year
no male equivalent
declining estrogen levels
atrophy of reproductive organs and breasts
gradual thinning of skin and bone loss
hot flashes
increased total blood cholesterol and falling HDL
irritability and depression in some
Treatment
estrogen-progesterone preparations