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Justin Cabrera P.6 Reproductive system - Coggle Diagram
Justin Cabrera P.6
Reproductive system
Major functions of the Reproductive system (male and female)
Doesn't function continuously like other organ systems
Not active until puberty
4 tasks of Reproductive organs
Bring gametes from male and female together through sexual intercourse
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
Form specialized cells for sexual reproduction call gametes
Ova(eggs): gametes in females
Sperm: gametes in males
Support development of fetus (gestation) and birth of baby (parturition)
Male and female reproductive structures are homologous structures
Examples
male penis and female clitoris
male testes and female ovaries
Share a common origin during development
Spermatogenesis
process of forming male gametes
Begins at puberty
Occurs in seminiferous tubules
Anatomy of male reproductive structures
Primary sex organs (gonads)
Vital in development and function of reproductive organs and other organs/tissues, sexual behavior, sexual drives
testes (male)
Sex hormones (steroid hormones)
Testosterone (males)
Gametes
sperm (male)
mature in epididymis
highly coiled
pass slowly through at rate that takes ~ 20 days, when they finally gain ability to swim
Anatomy
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
sperm-producing male gonads that lie within the scrotum
Anatomy
Testis Tunics
Tunica albuginea
inner layer forms fibrous capsule
Tunica vaginalis
outer layer derived from peritoneum
Septa divide testis into ~250 lobules, each containing one to four seminiferous tubules
Site of sperm production
Sperm is conveyed from seminiferous tubules to straight tubule to rete testis to efferent ductules to epididymis
Epididymis is made up of the head, the body, and the tail
Sperm are stored in the tail until ejaculation
Sperm are stored in the tail until ejaculation
Accessory reproductive organs
ducts
carry sperm from testes to body exterior
Ductus deferens
Passes through inguinal canal to pelvic cavity
Joins duct of seminal vesicle to form ejaculatory duct
~ 45 cm long
Ejaculatory duct
Conveys both urine and semen
Epididymis
During ejaculation, epididymis contracts, expelling sperm into ductus deferens
Smooth muscle in walls propels sperm from epididymis to urethra
Urethra
external genitalia
The Scrotum
Sac of skin and superficial fascia
Midline septum divides scrotum into two compartments, one for each testis
Contains paired testes
Lower temperature necessary for sperm production
3°C lower than core body temperature
Scrotum is affected by temperature changes
Hangs outside abdominopelvic cavity at root of penis
Penis
male copulatory organ
Consists of
Prepuce, or foreskin: cuff of loose skin covering glans
Root and shaft that ends in glans penis
Corpora cavernosa
paired dorsal erectile bodies
Corpus spongiosum
surrounds urethra and expands to form glans and bulb of penis
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
Erection
erectile tissue fills with blood, causing penis to enlarge and become rigid
glands
prostate
Consists of smooth muscle that contracts during ejaculation
Secretes milky, slightly acid fluid
Plays a role in sperm activation
Enters prostatic urethra during ejaculation
Contains citrate, enzymes, and prostate-specific antigen (PSA)
Makes up one-third of semen volume
Encircles urethra inferior to bladder
bulbo-urethral glands
Lubricate glans penis
Neutralize traces of acidic urine in urethra
Produce thick, clear mucus during sexual arousal
seminal glands
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
Contains smooth muscle that contracts during ejaculation
Semen
Milky-white mixture of sperm and accessory gland secretions
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
Delivery of sperm
ductus deferens
ejaculatory duct
epididymis
urethra
Anatomy of female reproductive structures
Primary sex organs (gonads)
ovaries (female)
Sex hormones (steroid hormones)
estrogens and
progesterone (females)
Gametes
ova (females)
paired structures flank the uterus, are almond shaped and about twice as large
Ligmanets
Suspensory ligament
anchors ovary laterally
to pelvic wall
Ovarian ligament
anchors ovary medially to uterus
Suspensory ligament and mesovarium are part of broad ligament that supports uterine tubes, uterus, and vagina
Ovarian follicles
tiny saclike structures embedded in cortex
Each month a ripened follicle ejects oocyte in event called ovulation
Contain immature egg (oocyte) encased by one or more layers of very different cells
Vital in development and function of reproductive organs and other organs/tissues, sexual behavior, sexual drives
Accessory reproductive organs
ducts
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
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
Regions of uterus
Body
major portion
Fundus
rounded superior region
Isthmus
narrowed inferior region
Cervix
narrow neck, or outlet; projects into vagina
Cervical canal
Uterine body via internal os
Vagina via external os
Function is to receive, retain, and nourish fertilized ovum
Uterine wall
Myometrium
bulky middle layer consisting of interlacing layers of smooth muscle
Contracts rhythmically during childbirth
Endometrium
mucosal lining
Fertilized egg burrows into endometrium and resides there during development
Simple columnar epithelium on top of a thick lamina propria
Perimetrium
outermost serous layer (visceral peritoneum)
Uterine tubes(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
glands
Mammary Glands
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
external genitalia(vulva or pudendum)
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
Counterpart of penis, body of clitoris has erectile tissue
anterior to vestibule
Perineum
Diamond-shaped region between pubic arch and coccyx
Reproductive role of female more complex because of pregnancy
Internal genitalia
Events of the female hormonal cycles (be sure to include all categories)
Oogenesis
production of female gamete
Fetal period
Primary oocytes
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
Ovarian follicle
functional unit of ovary that encloses a single oocyte
Follicles go through stages of development
Secondary follicles
have multiple layers of granulosa cells surrounding primary oocyte
Vesicular (antral) follicles((tertiary follicles))
have a fluid-filled cavity called an
antrum
Antrum: large cavity that is formed when all fluid coalesces
Antrum continues to expand with fluid isolating oocyte
Before ovulation primary oocyte inside vesicular follicle resumes meiosis and becomes secondary oocyte
Primordial follicle
single layer of squamous pre-granulosa cells surrounding primary oocyte
first to develop in fetus
Primary oocytes are arrested in prophase I
Only small fraction recruited into pool
Primary follicle
Primary follicle now called secondary follicle
Oocyte secretes glycoprotein-rich substances that forms zona pellucida that encapsulates oocyte
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
Maturation processes occurs in two phases
Phase 1: gonadotropin-independent pre-antral phase involves intrafollicular paracrines
antral phase stimulated by FSH and LH
Dominant follicle is selected
Primary oocyte resumes meiosis I
Ovarian cycle
monthly (~28 day) series of events associated with maturation of egg
Phases
Follicular phase
period of vesicular follicle growth (days 1–14)
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
Other non-dominant follicles will undergo atresia
Dominant follicle outcompetes other follicles and is only one to continue on
Primary oocyte of dominant follicle completes meiosis I to form secondary oocyte and first polar body
Luteal phase
period of corpus luteum activity (days 14–28)
Follicular phase varies, but luteal phase is always 14 days from ovulation to end of cycle
Remaining cells form corpus luteum
After ovulation, ruptured follicle collapses, and antrum fills with clotted blood
Corpus luteum secretes progesterone and some estrogen
If no pregnancy occurs, corpus luteum degenerates into corpus albicans
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
Hormonal Regulation of the Ovarian Cycle
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
3.Negative feedback inhibits gonadotropin release
GnRH stimulates FSH and LH secretion
4.Positive feedback stimulates gonadotropin release
Estrogen levels continue to rise as a result of continued release by dominant follicle
Triggers LH surge
5.LH surge triggers ovulation and formation of the corpus luteum
Shortly after ovulation
LH transforms ruptured follicle into corpus luteum
LH stimulates corpus luteum to secrete progesterone and some estrogen almost immediately
Progesterone helps maintain stratum functionalis
Maintains pregnancy, if it occurs
Estrogen levels decline
Negative feedback inhibits LH and FSH release
If no fertilization occurs
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
Corpus luteum degenerates when LH levels start to fall
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
Rising estrogen levels prompt generation of new stratum functionalis layer
As layer thickens, glands enlarge, and spiral arteries increase in number
Ovulation occurs at end of proliferative phase on day 14
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
Gonadotropin levels are beginning to rise
Stratum functionalis detaches from uterine wall and is shed
Menstrual flow of blood and tissue lasts 3–5 days
Ovarian hormones are at lowest levels
By day 5, growing ovarian follicles start to produce more estrogen
Disorders associated with the reproductive system (including STI’s)
Testicular cancer
Risk Factor
Cryptorchidism is most common risk factor
Nondescent of testes
Having mumps that lead to orchitis (inflammation of testis) could be a risk factor
Rare, but most common cancer in men age 15–35
Treatment
radiation / chemotherapy
Sign: painless, solid mass in testis
Prostatitis
Prostate cancer
Digital exam screening
Treated with surgery and sometimes radiation
Metastatic prostate cancer treated with drugs that block testosterone synthesis or action
Cervical cancer
Gardasil: three-dose vaccine; protects against HPV
Risks
STIs, including HPV
frequent cervical inflammation
multiple pregnancies
Breast Cancer
Risk factors
No pregnancies or first pregnancy late in life
No or short periods of breast feeding
Early onset of menstruation and late menopause
Family history of breast cancer
10% due to hereditary defects, including mutations to genes BRCA1 and BRCA2
Usually arises from epithelial cells of smallest ducts that eventually metastasize
Treatment
Radiation/ Chemotherapy
Removal of breast
Menopause
No equivalent to menopause in males
Declining estrogen levels cause:
Has occurred when menses have ceased for an entire year
Treatment: estrogen-progesterone preparations has been given for years
Methods and Classification of contraceptives
Mechanical
Internal Condom
A pouch worn inside the area of insertion such as the vagina or anus
External Condomn
A latex covering that is over the penis to prevent sperm from entering the vagina
Diaphragm
dome-shaped silicon cup inserted in the vagina hours before sex
Chemical
Injectables
A shot inserted into the arm, hip, or beneath the skin & injects progesterone derivatives to prevent maturation and ovulation
Spermicide
A chemical put within the vagina to kill sperm
Behavioral
Pill
Voluntary regulation of number of offspring via medication
Fertility awareness
Method which involves monitoring fertility
Withdrawl
Method to remove penis prior to ejaculation
Surgical
Sterilization
Female
A small section of the fallopian tubes is removed
Vasectomy(Male)
A small section of the vas deferens is removed
IUD
a t-shaped device of plastic inserted into the uterus to provide birth control
Hormones of the reproductive system (male and female)
Hypothalamic-Pituitary-Gonadal (HPG) Axis
Inhibin
released from gonads of both male and female
Exerts negative feedback on FSH release from anterior pituitary
Sex hormones
estrogen and progesterone (females)
act at target tissues in body
Exert negative feedback on hypothalamus and anterior pituitary
Pregesterone
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
Estrogen
Support rapid short-lived growth spurts at puberty
Induce secondary sex characteristics
Growth of breasts
Increased deposit of subcutaneous fat (hips and breasts)
Widening and lightening of pelvis
Exert anabolic effect on female reproductive tract
Estrogen also has metabolic effects:
Maintains low total blood cholesterol and high HDL levels
Facilitates calcium uptake
Promote oogenesis and follicle growth in ovary
testosterone (males)
Male secondary sex characteristics
features induced in nonreproductive organs by male sex hormones
Boosts basal metabolic rate
Basis of sex drive (libido) in males
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
Skeletal muscles increase in size and mass
Bones grow, increase in density
Deficiency leads to atrophy of accessory organs, semen volume declines, and erection/ejaculation are impaired
treatment: testosterone replacement
Prompts spermatogenesis and targets all accessory organs
Has multiple anabolic effects throughout body
Gonadotropin-releasing hormone (GnRH)
Released from hypothalamus reaches anterior pituitary cells via hypophyseal portal system
Luteinizing hormone (LH)
gonadotropins released from anterior pituitary
Follicle-stimulating hormone (FSH)