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Lina Le Period 6 Reproductive System - Coggle Diagram
Lina Le Period 6 Reproductive System
Major functions of the Reproductive System (male and female)
Reproductive system isn't continuous; it is activated after puberty
Male and Female reproductive organs are different, but share the same four general tasks
Combine genetic information contained within gametes through fertilization
Zygote is formed when sperm and egg fuse
Zygote is first cell of new individual and all body cells arise from it
Support development of fetus(gestation) and birth of baby(parturition)
Bring gametes from male and female together through sexual intercourse(copulation)
Form specialized cells for sexual reproduction call gametes
Sperm - gametes in males
Ova (eggs) - gametes in females
Anatomy of Male Reproductive Structures
Testes : sperm-producing male gonads that lie within the scrotum
Each testis is surrounded by two tunics
Tunica vaginalis: outer layer derived from peritoneum
Tunica albuginea: inner layer forms fibrous capsule
Septa divide testis into ~250 lobules, each containing one to four seminiferous tubules
site of sperm production
Spermatic cord encloses nerve fibers, blood vessels, and lymphatics that supply testes
Sperm is conveyed from seminiferous tubules to straight tubule →rete testis →efferent ductules →epididymis
Epididymis is made up of the head, the body, and the tail
Sperm are stored in the tail until ejaculation
Accessory ducts: sperm in delivered to body through system of ducts
epididymis
where sperm mature
highly coiled
pass slowly through at rate that takes 20 days, when they finally gain ability to swim (can be stored several month)
during ejaculation, epididymis contracts, expelling sperm into ductus deferens
ductus deferens (vas deferens)
45 cm long
passes through inguinal canal to pelvic cavity
joins duct of seminal vesicle to form ejaculatory duct
smooth muscle in walls proels sperm from epididymis to urethra
ejaculatory duct
urethra
conveys both urine and semen (at different times)
Accessory sex glands
Prostate
consists of smooth muscle that contracts during ejaculation
Secretes milky, slightly acid 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
encircles urethra inferior to bladder
Bulbo-urethral glands (Cowper's gland)
Produce thick and clear mucus during sexual arousal
Lubricate glans penis
neutralize traces of acidic urine in urethra
Seminal glands(seminal vesicles)
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 of seminal gland joins ductus deferens to form ejaculatory duct
Scrotum : sac of skin and superficial fascia
Hangs outside abdominopelvic cavity at root of penis
Contains paired testes
3°C lower than core body temperature
Lower temperature necessary for sperm production
Midline septum divides scrotum into two compartments, one for each testis
Scrotum is affected by temperature changes
Penis : male copulatory organ
external genitalia
consists of:
root and shaft that ends in glans penis
prepuce, or foreskin: cuff of loose skin covering glans
Internally, penis made up of spongy urethra and three cylindrical bodies of erectile tissue, spongy network of connective tissue and smooth muscle with vascular spaces
Corpus spongiosum: surrounds urethra and expands to form glans and bulb of penis
Corpora cavernosa: paired dorsal erectile bodies
Erection: erectile tissue fills with blood, causing penis to enlarge and become rigid
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
Sperm
Major regions of sperm
Midpiece: metabolic region containing mitochondria that produce ATP to move tail
Tail: locomotor region that includes flagellum
Head: genetic region that includes nucleus and helmetlike acrosome containing hydrolytic enzymes that enable sperm to penetrate egg
Spermatogenesis: process of forming male gametes
begins at puberty, around 14 years of age
Adult males make 90 million sperm daily
occurs in seminiferous tubules
Anatomy of Female Reproductive Structures
Internal genitalia: located in pelvic cavity
Duct System
vagina
Thin-walled tube 8–10 cm (3–4 inches) in length
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
uterus
Hollow, thick-walled, muscular organ
Function is to receive, retain, and nourish fertilized ovum
Regions of uterus
Isthmus: narrowed inferior region
Cervix: narrow neck, or outlet; projects into vagina
Fundus: rounded superior region
Body: major portion
Cervical canal communicates with:
Vagina via external os
Uterine body via internal os
Uterine wall
Three layers of wall
Endometrium: mucosal lining
Fertilized egg burrows into endometrium and resides there during development
Simple columnar epithelium on top of a thick lamina propria
Myometrium: bulky middle layer consisting of interlacing layers of smooth muscle
Contracts rhythmically during childbirth
Perimetrium: outermost serous layer (visceral peritoneum)
uterine tubes
Uterine tubes, also called fallopian tubes or oviducts, receive ovulated oocyte and are usual site of fertilization
Each tube ~10 cm (4 in) long and extends from area of ovary to superior region of uterus
Regions of uterine tube
Infundibulum: funnel-shaped opening into the peritoneal cavity
Margin contains ciliated projections called fimbriae that drape over ovary
Is site where fertilization usually occurs
During ovulation, uterine tube captures oocyte
Oocyte is carried along toward uterus by smooth muscle peristalsis and ciliary action
Ovaries : female gonads
Produce female gametes (ova)
Secrete female sex hormones, estrogen (estradiol, estrone, estriol), and progesterone
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
Suspensory ligament and mesovarium are part of broad ligament that supports uterine tubes, uterus, and vagina
Each ovary is held in place by several ligaments
Suspensory ligament: anchors ovary laterally to pelvic wall
Ovarian ligament: anchors ovary medially to uterus
Ovaries – paired structures flank the uterus, are almond shaped and about twice as large
External genitalia: external sex organs
Labia majora: hair-covered, fatty skin folds
Counterpart of male scrotum
Labia minora: skin folds lying within labia majora
Mons pubis: fatty area overlying pubic symphysis
Vestibule: recess within labia minora
Clitoris: anterior to vestibule
Counterpart of penis, body of clitoris has erectile tissue
Mammary glands
Mammary glands are present in both male and female, but normally function only in female
Main function is milk production to nourish newborn
Modified sweat glands consisting of 15–25 lobes
Areola: pigmented skin surrounding nipple
Lobules within lobes contain glandular alveoli that produce milk
Breast size is due to amount of fat deposits
Hormones of the Reproductive System (male and female)
Reproductive Hormones
Gonadotropin-releasing hormone (GnRH)
released from hypothalamus reaches anterior pituitary cells via hypophyseal portal system
Follicle-stimulating hormone(FSH) and Luteinizing hormone(LH)
gonadotropins released from anterior pituitary
Sex Hormones
Testosterone - dominating in males
synthesized from cholesterol, is transformed at some target cells
Prompts spermatogenesis and targets all accessory organs
Has multiple anabolic effects throughout body
Male secondary sex characteristics: features induced in nonreproductive organs by male sex hormones (mainly testosterone)
Appearance of pubic, axillary, and facial hair
Enhanced growth of hair on chest or other areas
Larynx enlargements causes deepening of voice
Skin thickens and becomes oily
Bones grow, increase in density
Skeletal muscles increase in size and mass
Boosts basal metabolic rate
Basis of sex drive (libido) in males
Deficiency leads to atrophy of accessory organs, semen volume declines, and erection/ejaculation are impaired; treatment: testosterone replacement
Estrogen and Progesterone - dominating in females
Estrogen
Promote oogenesis and follicle growth in ovary
Exert anabolic effect on female reproductive tract
Support rapid short-lived growth spurts at puberty
Induce secondary sex characteristics
Increased deposit of subcutaneous fat (hips and breasts)
Widening and lightening of pelvis
Growth of breasts
Estrogen also has metabolic effects:
Maintains low total blood cholesterol and high HDL levels
Facilitates calcium uptake
Progesterone works with estrogen to establish and regulate uterine cycle
Effects of placental progesterone during pregnancy
Helps prepare breasts for lactation
Inhibits uterine motility
Promotes changes in cervical mucus
Events of the Female Hormonal Cycles
The Ovarian Cycle : monthly (~28 day) series of events associated with maturation of egg
Follicular phase: period of vesicular follicle growth (days 1–14)
During follicular phase, several vesicular (antral) follicles become sensitive to FSH and are stimulated to grow
One dominant follicle becomes especially sensitive to FSH
FSH levels drop around middle of follicular phase
Dominant follicle outcompetes other follicles and is only one to continue on
Other non-dominant follicles will undergo atresia
Primary oocyte of dominant follicle completes meiosis I to form secondary oocyte and first polar body
After ovulation, ruptured follicle collapses, and antrum fills with clotted blood
Remaining cells form corpus luteum
Corpus luteum secretes progesterone and some estrogen
If no pregnancy occurs, corpus luteum degenerates into corpus albicans (scar) in 10 days
last 2–3 days of luteal phase, when endometrium begins to erode
If pregnancy occurs, corpus luteum produces hormones that sustain pregnancy until placenta takes over, at about 3 months
Two consecutive phases, with ovulation occurring midcycle between phases
Ovulation: Each month after puberty, a select few primary oocytes are activated (release of egg)
One from this group is “selected” each month to become dominant follicle
Caused by high hormonal levels, especially FSH
In-between Follicular and Luteal phase
Ballooning ovary wall ruptures, expelling secondary oocyte with its corona radiata into peritoneal cavity
1–2% of ovulations release more than one secondary oocyte, which, if fertilized, results in fraternal twins
Identical twins result from fertilization of one oocyte, then separation of daughter cells
Luteal phase: period of corpus luteum activity (days 14–28)
Hormonal interaction during ovarian cycle
Positive feedback stimulates gonadotropin release
Estrogen levels continue to rise as a result of continued release by dominant follicle
Triggers LH surge
LH surge triggers ovulation and formation of the corpus luteum
Shortly after ovulation:
LH transforms ruptured follicle into corpus luteum
Estrogen levels decline
LH stimulates corpus luteum to secrete progesterone and some estrogen almost immediately
Progesterone helps maintain stratum functionalis
Maintains pregnancy, if it occurs
Negative feedback inhibits gonadotropin release
FSH and LH stimulate follicles to grow, mature, and secrete sex hormones
FSH stimulates cells to release estrogen, and LH prods other cells to produce androgens, which converts to estrogens
Negative feedback inhibits LH and FSH release
GnRH stimulates FSH and LH secretion
If no fertilization occurs:
Corpus luteum degenerates when LH levels start to fall
Causes a sharp decrease in estrogen and progesterone, which in turn ends blockage of FSH and LH secretion, causing cycle to start all over again
Oocyte is actually activated 12 months prior to ovulation but matures 14 days before ovulation
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
Estrogen also increases synthesis of progesterone receptors in endometrium
Thins out normally thick, sticky cervical mucus to facilitate sperm passage
Ovulation occurs at end of proliferative phase on day 14
Rising estrogen levels prompt generation of new stratum functionalis layer
As layer thickens, glands enlarge, and spiral arteries increase in number
Days 15–28: secretory (postovulatory) phase
Endometrium prepares for embryo to implant
If fertilization does not occur:
Corpus luteum degenerates toward end of secretory phase; progesterone levels fall
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
Phase that is most consistent in duration
Days 1–5: menstrual phase
Stratum functionalis detaches from uterine wall and is shed
Menstrual flow of blood and tissue lasts 3–5 days
Gonadotropin levels are beginning to rise
By day 5, growing ovarian follicles start to produce more estrogen
Ovarian hormones are at lowest levels
Disorders Associated with Reproductive System
Testicular cancer
Sign : painless, solid mass in testis
90% cured by surgical removal of testis and often radiation or chemotherapy
Rare, but most common cancer in men age 15 - 35
Cryptorchidism is most common risk factor
nondescent of testes
Having mumps that lead to orchitis(inflammation of testis) could be a risk factor
Prostatis(prostate cancer): common reason for man to consult urologist
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 have high rate of false positives
Treated with surgery and sometimes radiation
Metastatic prostate cancer treated with drugs that block testosterone synthesis or action
Cervical cancer
Most common between ages 30 and 50
Risks: frequent cervical inflammation; STIs, including HPV; or multiple pregnancies
Gardasil: three-dose vaccine; protects against HPV
Recommended for 11- and 12-year-old girls
affects 450,000 women worldwide each year, killing half
Papanicolaou (Pap) smear 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 inactivity
Breast Cancer
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
70% of women with breast cancer have no known risk factors
Usually arises from epithelial cells of smallest ducts that eventually metastasize
10% due to hereditary defects, including mutations to genes BRCA1 and BRCA2
50% to 80% of women with these genes develop breast cancer
Greater risk of ovarian cancer as well
13% of women will develop condition
Diagnosis
Early detection via self-examination and mammography, a type of X-ray examination
American Cancer Society recommends screening every year for women age 40 and over
Invasive breast cancer is most common malignancy and second most common cause of cancer death in U.S. women
Treatment
Depends upon characteristics of lesion
Radiation, chemotherapy, or surgery often followed by radiation or chemotherapy to destroy stray cells
Drugs for estrogen-responsive cancers
Until 1970s, standard treatment was radical mastectomy that removes breast, with all underlying muscles, fascia, and associated lymph nodes
Lumpectomy: less invasive and excises only cancerous lump
Some women opt for breast reconstruction
STIs are also called sexually transmitted diseases (STDs) or venereal diseases (VDs)
Latex condoms help prevent spread
STIs are single most important cause of reproductive disorders
U.S. has highest rates of infection among developed countries
Bacterial STI
Chlamydia
Most common bacterial STI in United States
Caused by Chlamydia trachomatis
Can be contracted from birth canal by newborns
Responsible for 25–50% of all diagnosed cases of pelvic inflammatory disease (PID)
Symptoms: urethritis; penile and vaginal discharges; abdominal, rectal, or testicular pain;painful intercourse; irregular menses
Only 20% of women and 10% of men have symptoms
Left untreated, can lead to sterility
Newborns picking bacteria up from birth canal can develop:
Respiratory tract inflammations, including pneumonia
Conjunctivitis, a painful eye infection that can lead to corneal scarring if untreated
Treatment: antibiotics
Gonorrhea
Bacterial infection of mucosae of reproductive and urinary tracts
Caused by Neisseria gonorrhoeae
Most infections are asymptomatic
In males, symptoms can include urethritis, painful urination, discharge of pus from penis (penile “drip”)
Untreated can cause urethral constriction and inflammation of duct system
In females, symptoms can include abdominal discomfort, vaginal discharge, or abnormal uterine bleeding and possible urethral symptoms
Untreated can result in pelvic inflammatory disease and sterility
Treatment: antibiotics, but resistant strains are becoming prevalent
Treatment with at least two antibiotics is now required
Syphilis
Bacterial infection transmitted sexually or congenitally
Caused by Treponema pallidum
Infected fetuses can be stillborn or die shortly after birth
Bacteria invades mucosae or even broken skin
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
Appear for 3–12 weeks, then disappear
Pink skin rash, fever, and joint pain can develop
Disease can enter latent period, which may or may not progress to tertiary syphilis
Tertiary syphilis is characterized by gummas, lesions that develop in CNS, blood vessels, bones, and skin
Treatment: penicillin
Parasitic STI
Trichomoniasis
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
Viral STI
Human Papillomavirus (HPV)
Cause of genital warts
80% of cases of invasive cervical cancer are linked to some strains of HPV
Can also be a cause of some penile, anal and oropharyngeal cancers
Vaccination can guard against most common cancer-causing strains
Recommended for boys and girls before becoming sexually active
Group of ~40 or more viruses is most common STI in United States
Over 50% of adults are infected during lifetime
Genital Herpes
Caused by herpes simplex virus
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
Can be passed on to fetus
Congenital herpes can cause malformations
Treatment: antiviral drugs can reduce duration and intensity of flare-ups
Methods and Classifications of Contraceptives
Diaphragm
Mode of Protection
Mechanical
Effectiveness
typically 82% perfectly 86%
Internal Condom
Mode of Protection
Mechanical
Effectiveness
typically 79% perfectly 95%
21:100
Pill
Effectiveness
COC
typically 93%
perfectly 99.5%
POP
typically 93%
perfectly 99.5%
9:100
Mode of Protection
Chemical
External Condom
Mode of Protection
Mechanical
Effectiveness
typically 88% perfcetly 98%
18:100
Injectables
Mode of Protection
Chemical
Effectiveness
typically 96% perfectly 99.8%
6:100
Side Effects
irregular bleeding
bleeding between periods
loss of bone density
headaches
weight gain
nervousness
dizziness
Fertility Awareness
Effectiveness
typically 76-93%
perfectly 95-99.5%
Mode of Protection
Behavioral
IUD
Effectiveness
Hormonal : 99.9%
Copper 99.5%
Less than 1:100
Side Effects
Copper
spotting
heavier and longer periods
cramps
Progestin
irregular bleeding
no periods
abdominal/pelvic pain
Mode of Protection
Surgical
Withdrawal
Mode of Protection
Behavioral
Effectiveness
typically 80% perfectly 95%
Male Sterilization
Mode of Protection
Surgical
Effectiveness
99.5%
Less than 1:100
Side Effects
bleeding
infection
pain
Spermicides
Mode of Protection
Chemical
Effectiveness
diaphragm 12:100
cervical cap 17-23:100
alone 28:100
sponge 12-24 : 100
Female Sterilization
Effectiveness
99.5%
Less than 1:100
Mode of Protection
Surgical
Side Effects
pain
infection or other complications after surgery
bleeding