Lecture 11: Female reproductive system Flashcards
What is the function of the female reproductive system
- to produce offspring and ensure continuity of the genetic code
- to produce eggs, or female gametes, each can unite with male gamete to form the first cell of an offspring
- to provide nutrition and protection to the offspring for up to several years after conception
What are the 4 parts that make up the female reproductive system
- Gonads
- Hormones
- Organ systems
- Reproductive cycles
What are the Gonads
- ovaries (oogenesis occurs here)
- gamete: 2nd oocyte (can lead to ovule)
What are the hormones of female reproductive sys.
- Estrogen & Progestrone
- Inhibin & Relaxin
What are the 3 parts of the organ system
- Internal genitalia (ovaries & duct system)
- External genitalia (Vulva)
- Accessory organs (mammary glands)
What are the 3 independent reproductive cycles of female repro sys
- Ovarian cycle (oogenesis & developmentt of folicles)
- Menstrual cycles (shedding of the endometrium of the uterus)
- Hormonal cycle (control of the other 2 cycles & mammary gland -> secretion and production)
what is structure and location of ovaries
- site of female gamete production
- homologus to the testes of the male
- held in peritoneal cavity by many ligaments
What are the 3 ligaments holding ovaries in place
- Broad ligament (attaches the ovaries to the uterus)
- Ovarian ligament (holds ovary to uterus)
- Suspensory ligament (attaches the ovaries to the pelvic wall)
How does irrigation work in the ovaries
- abdominal aorta sends to the ovarian artery
- internal iliac artery sends to a branch of the uterine artery
- ovarian veins form the PAMPINIFORM plexus
Structure of germinal epithelium in ovaries
- external covering
- continuous w/ peritoneum
- cuboidal or squamous epithelium
- covering ovaries
What is structure of tunica Albuginea of ovaries
- internal capsule
- made of c.t.
what is structure of cortex of the ovaries
- dense layer
- highly vascularized
- containing ovarian follicles
What do the ovarian follicles contin
- Oocytes (immature future ovules at diff stages of devel) & a few layers of epithelial tissue that surrounds them
- all devel in first 6 months of fetus life
- have ~ 400, 000 total but only 400 survive
- 400/ 12 mnths = 33 years after puberty to have a baby
What is structure of medulla of ovaries
loose tissue housing blood vessels & nerves
What does oogenesis genrate
the female gamete
What is the progress of oogenesis
primary oocyte -> secondary oocyte -> ovum
How many Oocytes develop at a time and how does this differ from spermatogonium
-1 oocyte will develop at a time
vs
-4 spermatozoa
What happens to first and second polar bodies
they are broken down and then reabsorbed
What is first form of follicular phase
-primordial follicle
then becomes primary follicle
When does primordial follicle become primary follicle
when the 1 layer of follicular cells surround oocyte
What happens when follicular cells of primary follicle proliferate
- they become stratified
- take on a new name : Granulosa cell
What is the name of the connective tissue (c.t.) that forms around the primary follicle
Theca cells (internal & external)
What do the internal theca cells secrete
androgens
What do Granulosa cells do to androgens secreted by the internal theca cells
converts them to estrogen
What does the external theca cells transform into
fibrous capsule
What forms the thick transparent membrane around the primary oocyte aka ZONA PELLUCIDA
granule cells secrete a rich substance in glycoproteins (receptors for spermatozoa)
When the ZONA PELLUCIDA is secreted around the primary oocyte what stage of follicular phase is that
secondary follicle
What is the ANTRUM
a cavity between granule cells filled with follicular liquid
What do you call the granulosa cells that surround the zona pellucida that is secreted by the oocyte
corona radiata
What is name for follicle at maximum size
Vesicular (Graafian) follicle
10-12mm
What is size of ovum
~120um
-which = ~ 250,000 times the size of sperm
Why does Graafian follicle bulge from surface of the ovary
so that it will rrupture
What is released into the peritoneal cavity after the Graafian follicle ruptures from the ovary and what is this process called
- secondary oocyte and corona radiata are released
- this is called ovulation
What is the process called Atresia
-many follicles are at different stages of maturation but only 1 becomes the dominant follicle and continues on to ovulation while the others degenrate
What comes after follicular phase
Luteal phase
What happens to Graafian follicle after the evacuation of follicular liquid (luteal phase)
- Graafian follicle flattens
- antrum if filled with coagulated blood
- blood is absorbed by granulosa cells (corpus hemorrhagicum)
What happens after granulosa cells absorb blood in luteal phase
Granulosa cells hypertrophy
- fuses w/ the internal theca cells
- forms the corpus luteum
- “yellow body”
What is the transient endocrine gland formed in the luteal phase
corpus luteum
What does the Corpus Luteum secrete
- Progesteron
- a bit of Estrogen
- Inhibin (suppress FSH and development of more follicles)
What happens to Corpus Luteum if there is NO pregnancy
- begins to degenerate after 10 days
- stops producing hormones
What happens to Corpus Luteum if there IS pregnancy
-it will be active until placenta is ready to secrete hormones in its place
~ the end of 3 months where corpus luteum will degenerate & ovaries will remain inactive until delivery (parturition)
What hormone regulates ovarian cycle
fluctuation of gonadotropin levels
Ovarian cycle is correlated with what other cycle
uterine cycle
Fluctuations of what hormone levels will cause endometrial changes
fluctuations of ovarian hormone levels
What are the hormones involved with ovarian cycle
FSH: follicle stimulating hormone
LH: luteinizing hormone
-both peak at ovulation day 14
Uterine cycle is a series of what and occurs in response to what hormones
- series of cyclic modifications that occur to the uterus’ endometrium
- occurs each month in response to estrogen and progestrone
Uterine cycle occurs in how many phases
3
When does uterine cycle occur
before ovulation
-corresponds to follicular phase
what are the phases of uterine cycle
- Menstrual
- Proliferative
- Secretory
What is the Menstrual phase
- shedding of endometrium
- about 3 - 5 days
- cycle start at 1st day of menstruation
- ordinarily sterile
- production of fluid ~ 50-150ml
What is menstrual flow composed of
- blood
- interstitial fluid
- mucus
- epithelial cells of the endometrial functional layer
What Triggers menstrual phase
-decreases in estrogens & progesterone to their lowest levels
What is the proliferative phase
- rebuilding endometrium after ovulation
- corresponds to luteal phase
- with estrogen stimulation basal layer generates new functional layer (proliferation of endometrial cells)
How long does proliferative phase last
~ 9 days but is most variable phase
What are signs of ovulation at the end of proliferative phase
- increases in temperature (~0.5 degrees C)
- changes in cervical mucus from changes in estrogen and progesterone (clearer, more crystalline favoring passage of spermatozoa)
When does fertility peak in regards to temp
24hrs after temp spike
What is the Secretory phase
- endometrium is preparing for implantation of embryo
- lasts 14 days
what happens in secretory phase if there is no fertilization
-corpus luteum degenerates & the functional layer falls
What happens in secretory phase if there is fertilization
- corpus luteum is maintained
- implantation takes place & the development of the placenta progresses
What regulates the GnRH (gonadotropin-releasing hormone)
the Hypothalamus
What regulates the FSH & LH gonadotropins
- anterior pituitary
- estrogen / progesterone
What regulates inhibin / relaxin
-granulosa cells / corpus luteum & placenta
What is another word for menstruation
Menarche
What happens after 1st menarche
- adult secretion cycle is reached
- regular pattern reached around 3rd year
What are other names for the uterine tubes
- fallopian tubes
- Oviduct
What are he uterine tubes
- tubes that bring secondary oocyte to uterus
- NOT in direct contact with ovary
- supported by broad ligament
- measure ~ 10cm
What are the 3 layers of the wall of the uterine tubes
- Mucosa
- Muscularis
- Serosa
What is structure and function of mucosa layer of the uterine tubes
- simple columnar epithelial w/ ciliated cells
- w/ numerous folds
- ciliated cell facilitate movement of secondary oocyte
What is structure and function of muscularis layer of uterine tubes
- smooth muscle
- peristaltic movement of offspring toward uterus
What is the serosa layer of the uterine tubes
visceral peritoneum
What are the 4 secondary ovocyte collectors
- Isthmus
- Ampulla
- Infundibulum
- Frimbriae
What is the Ampulla
the normal site for fertilization
- from there zygote takes 3-7 days to get to uterus
- many divisions made on this journey but it arrives as the Blastocyst
What happens if the zygote does not reach a proper are like the uterus
= Ectopic pregnancy if zygote in: -uterine tubes -ovaries -peritoneal cavities -cervix
What is the usual end result of ectopic pregnancy
-spontaneous abortion with abundant hemorrhaging
What is the uterus
-hollow organ with thick walls functioning to receive, house & nourish zygote
Where is the uterus located
- between the rectum an base of urinary bladder, ordinarily inclined towards the front
- supported by ligaments & muscles
What are the ligaments that support the uterus
- broad, uterosacral & round (paired)
- anterior, posterior (single) ligaments
- Mesometrium (broad ligament)
What is a retroverted uterus
when uterus is inclined toward the back
-more likely in older women
What is uterine prolapse
when muscles tear during delivery
-uterus drops down up to cervix and bulges out from the vagina
Where do the Uterine arteries branch from
they are a branch of the internal iliac artery (hypogastric artery)
- right and left
- forms vascular layer of myometrium
What does the straight artery of uterus supply
the basal layer
what does the spiral artery of uterus supply
- the functional layer
- undergoes repeated degeneration & regeneration
- their spasm promotes the desquamation
What do the veins of the uterus form
- an extended network
- a few sinuses
What is the fundus
rounded top part above the uterine tubes insertion point
what is the Body of the uterus
largest part
-has the uterine cavity where implantation happens
what is the Isthmus
-narrow part btw the cervix and body
What is the cervix
-very narrow (neck), opening of the uterus
what do you call the cavity of the cervix and what does it do
CERVICAL CANAL
-communicates w/ vagina by external os & w/ uterus via internal os
What do the glands in mucosa of cervix in uterine wall produce
- cervical mucus
- forms the cervical plug preventing vaginal bacteria & spermatozoa to enter the cervix
What makes up the cervical mucus in uterine wall
H2O glycoproteins proteins lipids enzymes organic salt
What happens to cervical mucus during ovulation
- becomes alkaline to promote safe-haven for vagina (acidic) fleeting sperm
- provides nutrients for sperm & may have role in their capacitation
What are the 3 parts of the uterine wall
- Endometrium
- Myometrium
- Perimetrium
What is the myometrium of the uterine wall
- thick layer
- 3 layers of smooth muscle (intertwined bundle-circular, longitudinal, oblique)
- contract under oxytocin (hormone of posterior pituitary) during delivery
What is the perimetrium of uterine wall
-thin serosa (membrane)
What is structure of the vagina
~ 10 cm
- located btw the urinary bladder & rectum
- under epithelium there is a layer of c.t. with many ridges called Rugae
What is function of the vagina
-serves as a passage to and from uterus
What is the Hymen
- fold of vascularized mucosa situated at vaginal orifice
- often stretched w/ 1st sexual intercourse
What is the role of rugae
-stimulate the penis during sexual intercourse
What are the 3 parts of the vaginal wall
- Mucosa
- Muscularis
- Adventitia
What is the mucosa layer of the vaginal wall
- non keratinized stratified squamous epithelia (protection against friction)
- no glands: (lubricated by vestibular glands, epithelial cells release glycogen that is transformed by bacterial flora in lactic acid to maintain ph)
- PH (protect against infections)
What is the muscularis layer of vaginal wall
- 2 layers of smooth muscle capable of stretching alot
- circular, longitudinal
What is adventitia layer of vaginal wall
fibroelastic
(vulva)
what is mons pubis and role
adipose tissue, hair
-protects pubic symphyses during sexual intercourse
What is Labia and role
Labia majora
- homologous of male scrotum
- skin (adipose tissue, sweat glands, hair)
- protect genitalia
Labia minora
- skin
- no hair, sebaceous glands
What is the clitoris
- homologous of male penis
- small mass of erectile tissue that has 2 corpora cavernosa
- covered w/ prepuce and can swell following sexual arousal
What is the bulb of vestibule
- homologous to bulb & corpus spongiosum of male penis
- 2 masses of erectile tissue under labia majora on each side of vaginal orifice
- during sexual intercourse, bulb fills up w/ blood & tightens the vaginal orifice
What is the vestibule of the vulva
- space btw labia minora
- includes vaginal orifice, urethral orifice & openings to the skene glands and greater vestibular glands
What are the skene glands
- aka Paraurethral / vestibular minor
- homologus to the male prostate
- in wall of urethra, open on each side of urethral orifice
- secretes mucus
What are the greater vestibular glands
- aka Bartholin
- homologous of male bulbourethral glands
- opens on each side of vaginal orifice
- secrete mucus (lubrification during sexual intercourse)
What are mammary glands
modified sweat glands found in breast
-non funtional but present in males
What is structure of mammary glands
- 15 to 25 lobes separated by adipose tissue
- each lobe has many lobules containing breast milk
What determines volume of breast
- capacity to produce milk
- also quantity of adipose tissue
why do breasts get bigger when pregnant
- non pregnant female has underdeveloped lobules and ducts
- these develope perinatal
What is the areola
bumpy & pigmented region around the nipple
- rich in sebaceous glands that protect the nipple during feedings
- autonomic nervous system controls smooth muscle fibers of areola & nipple (promotes erection w/ tactile stimulation)
What is lactation
production of milk & its ejaculation
What is the milk excretion path
- alveoli (production) -> secondary tubules -> intralobar ducts -> lactiferous ducts w/ lactiferous sinuses (storage of milk btw feedings) -> nipple
- Colostrum is produced initially (IgA) then real milk after
When estrogen, progesterone & lactogen ( placental hormones) increase near end of prego it stimulates what to release
PRH (prolactin releasing hormone) by hypothalamus
- then the anterior pituitary secretes prolactin
What is released by hypothalamus in the positive feedback mechanism for the let down reflex (ejection of milk)
oxytocin
