Female reproduction system Flashcards
Ligamnets of the female reproductive system
The reproductive tract is suspended in a sheet of peritoneum called the broad ligament.
It is attached to the dorsal body wall
Carries blood vessels, nerves and lymphatics to the reproductive organs
Subdivided into segments supporting individual parts of the reproductive tract
Broad ligament is divided into the following:
Suspensory ligament of the ovary
Mesovarian, Mesosalpinx, Mesometrium
Round ligament
Ovaries are
Are the primary organs of reproduction in the female located in the abdomen near the kidneys
Normal size and shape varies from species to species and even among individuals within a species
Ovaries have two min functions
Production of ova
Production of the female sex hormones
Production of the ova are
The ovary has a predetermined number of oocytes within the ovary; these develop prior to birth. This is the total number available for the females’ lifetime. At each heat cycle oocytes are used.
Older oocytes have a greater chance of being damaged by toxic environments
Hormones produced by the ovaries
Estrogens
Progetins
Estrogen in the ovary is
Produced by developing follicle cells
Cause physical and behavioral changes that prepare an animal for breeding and pregnancy
Progestins in the ovary are
Primarily progesterone
Produced by corpus luteum (CL)
CL is the remnant of an empty follicle that has released an ova
Help prepare the uterus for implantation
Help maintain pregnancy after implantation
Ovarian cycle is
Cyclical pattern to the production of ova
An oocyte develops in a follicle → ovulation → CL forms → CL degenerates
Two hormones affect this cycle: FSH and LH (from anterior pituitary)
In all species, many follicles start to develop at the beginning of each cycle. Most fail to mature.
Uniparous spp means
: one oocyte and one offspring. i.e., horse, cow, human
Multiparous spp means
litters. i.e., dog, cat, pig
Primordial follicle is
Immature oocyte surrounded by a single layer of follicular cells
Many will be found in an ovary
Develop into primary follicles
Ovarian cycle- primary follicle is
With FSH, a primordial follicle becomes stimulated
Cells change shape from flat to cuboidal- called granulosa cells
Follicle is now a primary follicle
Only a few follicles respond to each FSH wave
Called follicular recruitment or follicular activation
In uniparous species, only one follicle will become dominant
Rest will regress and degenerate
Called follicular atresia
Ovarian cycle- secondary follicle is
Cells divide to create several cell layers around oocyte
Follicle is now a secondary follicle
Producing increasing amounts of estrogen to prepare for breeding and pregnancy
Develops a fluid-filled space between oocyte and granulosa cells – called the antrum
Primary oocyte divides producing a secondary oocyte
Ovarian cycle- mature follicle are and are called
Mature or Graafian follicle
Large, blister-like structure on ovary
At maximum estrogen production
Oocyte
Sits on stack of granulosa cells and is covered by thin layer of granulosa cells
Ovulation is
Rupture of surface of follicle
Explosive release of secondary oocyte also called the immature ovum
Spontaneous ovulators are
Some animals ovulate during a specific time in their estrus cycle
Induced ovulators are
In some animals like cat, rabbit and ferret, ovulation requires breeding
Corpus luteum is
Continued high LH levels cause corpus hemorrhagicum to change
Granulosa cells continue to multiply
What does the corpus luteum for in ovulation
Follicle fills with blood → clots → forms corpus hemorrhagicum
Stimulated by rising LH levels in most animals
Corpus luteum
Develops into a large, yellowish mass of cells known as the corpus luteum
Produces progestin hormones
Primarily progesterone
Important for maintaining pregnancy
Will regress quickly if does not receive signal from uterus that ovum has been fertilized and implanted
Oviduct is and does
Aka: uterine tube, fallopian tube
Paired convoluted tubes that extend from the tips of the uterine horns
Lumen of uterine horn is continuous with lumen of oviduct
They capture and transport ova from the ovary to the uterus and serve as the normal location for fertilization
Is the oviduct attached to the ovary and why
Not attached to the ovary
When ovulation takes place, the ova are expelled from the ovary and caught by the funnel shaped end of the uterine tube known as the infundibulum
They are then carried to the oviduct where fertilization normally occurs
Oviduct is composed of
The oviduct is composed of smooth muscle lined with highly folded mucus membrane with many ciliated cells
Both the cilia and muscle move the ova and possibly the spermatozoa.
What happens to ovulated eggs in the oviduct
Ovulated eggs are captured by the infundibulum although some occasionally sneak out through the opening into the peritoneal cavity
Usually disintegrate but sometimes become an ectopic pregnancy (implantation of fertilized ovum outside of the uterine cavity)
The oviducts gently conduct the fertilized ovum to the uterus for implantation
Uterus function and shape
A hollow muscular Y-shaped organ
Receives the fertilized ovum
Nourishes and houses the developing embryo
Expels the mature fetus through the birth canal.
Forms part of the placenta, which is the life support system that keeps the fetus alive while it develops
Major components are the body of the uterus, the uterine horns and the cervix.
A mucus membrane lines the uterus.
Its thickness and vascularity depends on hormonal changes from the ovary and pregnancy.
Bovine uterus shape
The mucosa has mushroom like projection or focal elevations called caruncles
Make up the maternal component of the placenta and give attachment to the fetal membranes
The caruncles grow during pregnancy and are used to determine the stage of pregnancy
Cervix is
The cervix projects caudally into the vagina
It is a heavy, smooth muscled sphincter that is tightly closed except during parturition or estrus (heat)
Cervix function
At estrus, the cervix relaxes slightly permitting spermatozoa to enter the uterus and then closes until parturition.
Mucus may discharge from the cervix and be expelled from the vulva at estrus
Mucus production by the cervix increases during pregnancy to prevent infections entering the uterus.
The vagina is not sterile
Vagina is
Extends from the cervix to the vulva
It is the female copulatory organ and part of the birth canal
Structurally it is a muscular tube which contains mucus glands for lubrication.
Vulva consists of
Composed of vestibule, the clitoris and the labia.
Vestibule is
the caudal part of the tubular portion of the reproductive tract, common to both urinary and reproductive system
Clitoris is
the female counterpart of the penis and is located on the floor of the vestibule
Labia on the vulva is
form the external boundary of the vulva
The estrous cycle is defined by
Defined as the time from beginning of one heat period to beginning of the next
Estrous is controlled by
Controlled by FSH and LH from the anterior pituitary gland
Stimulate production of hormones by:
Developing follicle – estrogens
Cause physical and behavioral changes of estrus
Corpus luteum – progestins
Prepares uterus and maintains pregnancy
How does estrous effect breeding
Timing of breeding depends on the estrous cycle of the female
Males can breed at any time
The estrous cycle is naturally timed to coordinate with seasons of food abundance to give greater reproductive success
What can stimulate estrous to begin
Onset may be stimulated by environmental changes, such as increasing daylength or temperature
Releases gonadotrophin-releasing hormone from hypothalamus
Acts on anterior pituitary to stimulate release of FSH
Estrous cycle intervals is classified by
Classified by number of cycles per year and when they occur
Polyestrous
Cycle continuously if not pregnant
Cattle, pigs, humans
Seasonally estrous is
Seasonal variations in cycling
Continuous at some times of year, absent at others
Horse, sheep, cat
Female cats usually cycle from January to late fall
Can start as early as 4 months of age
Diestrous is what
2 cycles per year – usually spring and fall
Dog
Monoestrous is
Usually only one cycle per year
Fox, mink
Stages of estrous is
Continuous process, but roughly divided into stages
Stages can be related to ovarian follicular development
In dogs, examination of vaginal smears can help identify the stage of estrous
Proestrous is
Follicular development in response to FSH
Increasing estrogen output from follicles
Causes physical preparation for ovulation and breeding
Thickening and development of lining of oviduct, uterus, and vagina
Vagina develops cornified layer to protect against trauma from breeding
Early proestrus looks like what on a cellular level
Epithelial cells are of intermediate and parabasal type.
Cells have a large nucleus, and lots of pale blue cytoplasm
Late proestus is
Many RBCs and WBCs (more vascular)
Epithelial cell are losing their nucleus and gaining keratin
Estrus is
Period of sexual receptivity
Peak estrogen levels
LH release and inhibition of further FSH
Mature follicles
Usually, ovulation occurs near end of estrus
Induced ovulators will have prolonged estrus if not bred
Mostly superficial, anucleate, keratinized cells
What will cats do if not breed
Cats are induced ovulators
Will stay in heat up if not bred
Follicle eventually regresses
Typically, in a week
Can be up to 2 weeks
No longer in heat
Can induce ovulation with Q-tip or hormone injection
Spaying is best
Metestrus is caused by
Corpus luteum (CL) develops after ovulation in response to continued LH presence
CL produces progesterone
Causes thickening of uterus lining in preparation for implantation
Inhibits follicular development
Diestrus is caused by
CL at maximum size and effect
If pregnant, CL will be retained in response to signal from developing embryo and uterus
If not pregnant, CL degenerates
fewer superficial cells,more intermediate cells and neutrophils
If CL degeneration is delayed (a common problem in intact bitches), it continues to prepare the body with hormones of pregnancy
Can result in pseudopregnancy
Animals develops enlarged mammary glands, may lactate, pelvis may relax, may nest-build and ‘mother’ stuffed toys
Most resolve spontaneously, but may require hormonal treatment to correct
Anestrus is
Ovarian inactivity between breeding cycles in all but the polyestrus species
