Module 1: Female Reproductive System Flashcards
What is the Hypothalamus composed of?
Surge and Tonic Centers
What is the Pituitary (hypophysis) composed of?
- Anterior Lobe (Adenohypophysis)
- Posterior Lobe (Neurohypophysis)
- Is the conduit that connects the brain to the anterior pituitary
- Is made up of two capillary beds, one in the median eminence and the other in the anterior pituitary
- Effect on Adenohypophysis
- Release of neuropeptide into Portal System
Portal System
Release of neuropeptide into capillaries in the Neurohypophysis
Hypothalamus
What hormone is released from the hypothalamus?
GnRH
(gonadotropin-releasing hormone)
What hormones are released from the anterior pituitary (relating to repro)?
- LH (Luteinizing hormone)
- FSH (Follicle-stimulating hormone )
- Prolactin (PRL)
What hormones are released from the posterior pituitary (relating to repro)?
Oxytocin
- GnRH, LH, FSH, Prolactin, Oxytocin
- Bind to Membrane Receptors
- Activate Signaling Cascade
Portein Hormones
- Progesteron, Estradiol, Testosterone
- Cross Plasma Membrane
- Bind to Nuclear Receptors
- Activate Transcription
Steroid Hormones
What hormones cause the testicles to make testosterone?
LH, coming from the pituitary
GnRH stimulates the pituitary gland to produce______________, the hormone responsible for starting follicle (egg) development and causing the level of estrogen, the primary female hormone, to rise
follicle stimulating hormone (FSH)
Does the hypothalamus produce estrogen and progesterone?
The hypothalamus controls estrogen production, but also your progesterone production
Where are Steroids From?
derived from cholesterol
HPG in the Male:
LH stimulates _____________ to use cholesterol to
produce ___________
Leydig cells, Testosterone
What causes a Negative Feedback, in blood, on the LH?
Testosterone
Where does most of the testosterone go to to support spermatogenesis?
Sertoli Cells
What Stimulates Sertoli Cells to mature sperm, produce ABP and Inhibin?
FSH
A protein found in the testicular cytosol or secreted by Sertoli cells in the rete testis fluid
ABP
What is secreted in the lumen of Semeniferous tubule and functions to concentrate testosterone locally?
ABP
Inhibin in blood causes a negative feedback loop on __________
FSH
The hypothalamus of females contains two functional areas responsible for secretion of GnRH
Surge & Tonic Centers
- During which phase does FSH/LH stimulate production of Estradiol by the pre-ovulary follicle?
- High E2 ________ LH surge
- Follicular Phase
- trigger
- During which phase FSH/LH stimulate production of Progesterone by Corpus Luteum Progesterone?
- High P4 ___________ GnRH/LH secretion
- Luteal Phase
- inhibits
HPG in the Female:
LH stimulates _________ to use cholesterol to produce ____________
Theca cells, Androgens
What diffuses into the Granulosa Cells?
Androgens
What stimulates conversion of Androgens to Estrodiol and secretion of Inhibin?
FSH
Inhibin in blood causes negative feedback on _______
FSH
What can have (+) or (-) feedback on GnRH/LH secretion depending on concentration and presence /absence of CL/Progesterone?
Estradiol
Low estradiol (E2) in the presensce of CL causes ___________ on GnRH
Negative feedback
High estradiol (E2) during estrus (+) the Surge Center to release lots of _____________and cause LH surge
GnRH
HPG in the Female, the two cell types are:
Theca Cells
Granulosa Cells
HPG in the Female, the two gonadotropin System are:
LH
FSH
- Is the major regulator of the female reproductive system.
- This regulation begins when GnRH is released from the hypothalamus at the onset of puberty, which stimulates LH and FSH production at the anterior pituitary.
The HPO axis
The Fate of Steroid Hormones:
Steroids secreted by gonad –> Steroid enters blood and goes to target tissue –> Steroid causes change in target tissue –> Steroid in blood passes through _________ –> Liver renders steroid H2O soluble (glucuronides and sulfates) –> Reenters blood and enters kidney or enters bile –> Excreted in urine and/or feces as glucuronide or sulfate
liver
The Fate of Steroid Hormones:
Steroids secreted by gonad –> Steroid enters blood and goes to target tissue –> Steroid causes change in target tissue –> Steroid in blood passes through Liver –> Liver renders steroid H2O soluble (glucuronides and sulfates) –> Reenters blood and enters ___________ or ___________ –> Excreted in urine and/or feces as glucuronide or sulfate
kidney, enters bile
In what species is the ovary “reversed” ?
Horse
produce gametes and hormones that influence the rest of the reproductive tract
Ovaries
optimal environment for fertilization and optimal pre-attachment
development of the early embryo
Oviduct
environment for sperm transfer, early Embryogenesis and site for attachment of the Conceptus
Uterus
barrier that secretes mucous in estrus and produces cervical seal in pregnancy
Cervix
copulatory organ that provides mucous for lubrication during estrous
Vagina
How many layers does the oviducts, uterus, cervix and vagina have?
4 Layers
- secretes substances vital for function of each region
- lined with different type of epithelium depending on organ
Mucosa
- Contains blood vessels, nerves and lymphatics
- Supports muscularis layer
Submucosa
- Circular (external) and longitudinal (internal) layers of smooth muscle
- Provides the organ the ability to contract which is essential for moving secretory products, gametes, embryos, and the fetus at parturition
Muscularis Layer
- continuous with peritoneum
- Single layer of squamous cells
Serosal Layer
In the cortex of the ovary you can find:
- Follicles
- Oocytes
- Theca
- Corpus lutea
In the medulla of the ovary you can find:
- Nerves
- Arteries and Veins
What does the Corpus Lutea produce?
- Relaxin
- Inhibin
- Oxytocin
- Activin
What is in the outer layer of the ovary (a connective tissue layer) ?
Tunica albuginea
What is a depression in Ovarian Medulla and site of Oocyte release in the mare?
Ovulation fossa
What is not part of the broad ligament, but is an attachment of the Ovary to the Uterus?
Utero-ovarian ligament or proper ligament of the ovary
Supports the ovaries and supplies the blood vessels, lymphatics, and nerves to the ovaries and forms the hilus
Mesovarium
- Thin, serous part of the broad ligament
- Supports the oviducts
- Forms a bursa that surrounds the ovary
- Orients the Infundibulum so that the Ova released at Ovulation have a high probability of entering the Oviduct
Mesosalpinx
In what species does the Mesosalpinx form a nearly complte ovarian bursa enveloping the ovary and keeping the ovary from view?
In the Bitch
- Largest and most conspicuous part of broad ligament
- Supports the uterine horns and body of uterus
Mesometrium
What are the three parts to the Uterine Tube? Describe
- Infundibulum
- contains the largest and it is the thinnest wall
- contains fibria to collect the Oocyte that is ovulated from the ovarian cortex - Ampulla
- Internal surface has many fern-like mucosal folds with ciliated epithelium
- intermediate region of the uterine tube - Isthmus
- Smaller than the ampulla
- More muscular wall and less mucosal folds than ampulla
** Uterotubal Junction is a critical in preventing unfertilized oocytes from entering the uterine horn.
- Two cervical canals that divide each horn into a distinct compartment
- A single vaginal canal that opens to exterior with two types of divisions
Duplex uterus
- Two uterine horns and a small uterine body with a single cervix
- Length of uterine body is dependent on degree of fusion between the paramesonephric ducts in the developing female fetus
Bicornuate Uterus
- Separation between the uterine horns is lacking
Simplex uterus
Name the species with Duplex uterus:
- Marsupials
- Rabbits
(two cervices)
Name the species with Bicornuate uterus:
Poorly to moderately developed uterine horns
- Mare
- Cow
Highly developed uterine horns
- Bitch
- Queen
- Sow
Name the species with Simplex uterus:
Primates (no uterine horns)
Can produce prostaglandin F2α during critical times of estrous cycle which causes regression of the Corpus Luteum if the animal is not pregnant
Endometrium
Ruminants have areas on the endometrium that are:
- Non-glandular
- Very vascular
- Protrude from surface of uterus
- Give rise to maternal portion of the placenta
Caruncles
- Develop from mucosa and become coiled in submucosa
- Secretory waxing and waning depending on stage of estrous cycle
Uterine Glands
- Endometrial folds
- Provide uterine surface for attachment of placenta
Sows and Horses
- Placental scars which are pigmented areas of endometrium which are previous placental attachment
- Bands around inside of uterus that are indicators of zonal placentation
- Zones of uterine repair that become less obvious with time
Queens
- Thick walled, non-compliant organ
- Primary function is to provide a barrier to spermatozoa in some species
- Isolates uterus in pregnancy using a layer of viscous mucous
Cervix
The cervix provides a barrier to which species?
Ewe
Cow
Bitch
The cervix is NOT a great barrier for spermatozoa in which species?
Mare
Sow
Serves as a copulatory organ and a site of expulsion during parturition
Vagina
In what species does the cervices protrude into the cranial vagina forming a Crypt known as the Fornix Vagina?
Mare
Cow
Bitch
a small tubular gland, pit, or recess
crypt
- Extends from external urethral orifice to labia
– Can thicken during estrous to mechanically protect vagina during copulation and prevent micro-organisms from entering the sub mucosa
– Can be secretory depending on the stage of estrous
Caudal Vagina or Vestibule
What can be used to determine the stage of the estrous cycle in the bitch, and can be determined by swabbing the vagina and examining the exfoliated cells?
Caudal vagina or vestibule
– External part of female reproductive tract
– Consists of two labia that meet medially to form two commissures
– Skin of labia is part of the integument
– Labia has adipose tissue and constrictor vulvae muscle that hold the labia together
Vulva
- In ventral commissure of the vulva
– Houses erectile tissue
– Covered with stratified squamous epithelium
– Wells supplied with sensory nerve endings
Clitoris
The three patterns of cyclicity are:
- Polyestrus
- Seasonally polyestrus
- Monoestrus
List species for Polyestrus cyclicity:
- Cattle
- Pigs
- Rodents
List species for Seasonally Polyestrus cyclicity:
- Horses
- Goats
- Sheeps
List species for Monoestrus cyclicuty:
- Dog
- Wolves
- Bears
List species for Seasonally Polyestrus cyclicity (Long Day):
Mare
** Spring breeding season
List species for Seasonally Polyestrus cyclicity (Short Day):
- Ewe
- Doe
- Elk
- Nanny
** Autumn breeding season
- Either promotes or inhibits reproduction depending on the species
- Is made by the Pineal Gland during the Dark
Melatonin
Melatonin is made during the dark, therefore in LONG DAYS breeders, more light means _______________ melatonin
Less
In what species is melatonin an inhibitory, therefore promoting cyclicity when there is lack of melatonin?
Mare (Long Day Breeders)
In what species does melatonin promote cyclicity?
In SHORT DAY breeders, LESS light means MORE melatonin
- Ewe
- Doe
- Elk
- Nanny
In SHORT DAY breeders, melatonin ___________ cyclicity, so they cycle during months that have _________ daylight (fall and winter)
promotes, less
↑ Daylight –> ↓ Melatonin –>↑ GnRH–> ↑ Ovarian Activity
Long Day Breeder
↓ Daylight –> ↑ Melatonin –> ↑ GnRH –> ↑ Ovarian Activity
Short Day Breeder
What are the Two phases of the Estrous Cycle?
- Follicular Phase (Estrus)
- Luteal Phase (Diestrus)
- Follicles are the dominant ovarian structure
- 20% of the estrous cycle
- Primary reproductive hormone is estradiol (E2)
Follicular Phase
- Period from ovulation until corpora lutea regression
- 80% of the estrous cycle
- Primary reproductive hormone is progesterone (P4)
Luteal Phase
Transition from period of Progesterone dominance to period of Estrogen dominance
Proestrus
Period of sexual receptivity and mating
Estrus
Transition from Estrogen dominance to Progesterone dominance
Metestrus
Period of maximum luteal function
Diestrus
List the four estrous cycle stages:
- Proestrus - Development of follicles
- Estrus - period of sexual receptivity
- Diestrus - CL formation
- Metestrus - Sustained, high progesterone secretion
Condition when female no longer exhibits regular cycles
Anestrus
Pregnancy, Lactation, Presence of offspring, Season, Stress and Disease are examples of:
Anestrus
is the longest stage of the estrous cycle because recognition of pregnancy happens during this phase
Diestrus
Oogenesis:
Where do the Primordial germ cells develop?
Yolk Sac
the production or development of an ovum
Oogenesis
The __________________ develop in the yolk sac and then migrate into the hindgut and finally to the UNdifferentiated Gonad
Primordial germ cells
Oocyte are arrested in ________________
Metaphase II
(T/F) Buhner Stitch doesn’t have to be removed prior to parturition
False
the vaginal discharge you have after giving birth
Lochia
In an induced ovulator species, which hormone must be triggered by the event of mating to induce ovulation?
LH
What is the site of PRODUCTION of Inhibin
Dominant Follicle
What is the site of the PRODUCTION of Progesterone
Ovaries
During oogenesis, the oocyte undergoes two meiotic arrests. What causes (triggers) the resumption of meiosis in each arrest, respectively?
LH surge; Fertilization
Which hormone is the primary luteolysin in the cow?
PGF2a
(T/F) Melatonin suppresses cyclycity in the short day breeder
False
Which are the criterias required to pursue medical management of pyometra in the bitch?
- Valuable breeding animal
- +/- Open cervix
- Young
- Good body condition
- Normal renal function
- No evidence of endotoxemia
In primary oocyte there are 4 (4n) cells that are _______________ at the end of first meiotic prophase
Nuclear arrest
(females are born with all 4 of these cells (they are arrested = not replicating))
(T/F) The ovaries of a mare are smaller than that of a fetus
True
(T/F) Standing heat in the bitch occurs in the presence of ELEVATED progesterone and DECREASED estradiol
True
After puberty there is ____________
LH surge
the ovarian structure that forms immediately after ovulation in known as a:
Corpus Hemorrhagicum
The endometrium corresponds to which layer of the uterus?
mucosal layer
Where is the SITE OF ACTION of the GnRH
Anterior Pituitary
Where is the SITE OF ACTION of the Inhibin
Anterior Pituitary
Males don’t have the ________ surge
LH
Where is the SITE OF ACTION of the LH
Thecal cells
Where is the SITE OF ACTION of the FSH
Granulosa cells
