Student Female Reproduction PDF

Dr. Jacqueline Mobley AHS 2220 Female  Reproduction   Learning Learn Goals Names, locations, functions of each part of the female reproductive system Learn The developmental stages and important structures in creating...

Dr. Jacqueline Mobley AHS 2220 Female  Reproduction   Learning Learn Goals Names, locations, functions of each part of the female reproductive system Learn The developmental stages and important structures in creating the ovum Learn The stages and hormonal influence of the estrous cycle  Introduction More complex than male anatomy Role: Make gametes Support pregnancy Support lactation      The Broad Ligament ▪ The reproductive tract is suspended from the dorsal body wall by sheets of peritoneum ▪ The broad ligaments ▪ Mesovarium → supports the ovaries ▪ Mesosalpinx → supports the oviduct ▪ Mesometrium → supports the uterus   Other ligaments ▪ Suspensory ligament: ▪ Cranial attachment of the broad ligament is to the body wall near the last rib ▪ Stretched/torn to allow for exteriorization of the ovary during OVH ▪ Round ligament ▪ Cord of fibrous tissue & smooth muscle on the free edge of the broad ligament ▪ Cut during OVH   OVH   Ovaries ▪ Ovaries are the female gonads ▪ Location: dorsal abdomen near kidneys ▪ Shape varies This Ph oto by Unknown Author is licensed und er CC BY ▪ Almond (most species) ▪ Bean (horse) ▪ Sow (grape clusters)  Ovarian Function ▪ 1) Produce gametes (oogenesis) ▪ 2) Produce hormones ▪ Estrogens ▪ Produced by follicles ▪ Behavioral changes & preparation for breeding/pregnancy ▪ Progestins ▪ Produced by corpus luteum ▪ Prepare uterus for implantation and maintaining pregancy ▪ Animals are BORN with a set number of oocytes  The Ovarian Cycle  ▪ Ova are produced in a cycle, as opposed to sperm which are produced constantly ▪ Cycle of events: ▪ Development of ova in a follicle ▪ Ovulation (release of ova from follicle) ▪ Formation of the corpus luteum (produces hormones to support pregnancy) ▪ Degeneration of unripened follicles ▪ Degeneration of corpus luteum   Ovarian cycle ▪ Hormones that control the cycle? ▪ Anterior pituitary gland ▪ Follicle stimulating hormone (FSH) ▪ Luteinizing hormone (LH) ▪ Quantity of eggs produced depends on species ▪ Uniparous species (horse, human, cattle) → one ova ▪ Multiparous species (cats, dogs, sows) → multiple ova   Follicular development – primordial follicle ▪ Primordial follicle = oocyte + thin layer of flat follicular cells ▪ FSH is released from anterior pituitary and acts on the follicular cells ▪ Only a few primordial follicles develop despite thousands present ▪ Known as follicular recruitment or follicular activation ▪ Growing follicle: an activated primordial follicle ▪ Zona pellucida (glycoprotein layer) forms around the oocyte ▪ Follicular cells grow and multiply, and turn into granulosa cells ▪ Granulosa cells produce estrogen ▪ Follicle continues to grow and produce greater amounts of estrogen ▪ A fluid filled space (antrum) is formed around the follicle  The mature follicle ▪ Mature follicle: a follicle at its maximal size ▪ AKA Graafian follicle and vesicular ovarian follicle ▪ Looks like a blister on the surface of the ovary ▪ Inside the follicle ▪ Oocyte sits on the cumulus oophorus (mound of granulosa cells) ▪ Zona pelucida is surrounded by the corona radiata (thin layer of granulosa cells) ▪ Large volume of fluid fills the antrum ▪ Peak estrogen production ▪ Ready for breeding  Ovulation ▪ Rising LH from the anterior pituitary triggers ovulation ▪ Follicle ruptures ▪ Oocyte is released into the oviduct ▪ Once ovulation occurs, oocyte become ovum ▪ Induced ovulators ▪ Will not ovulate unless breeding occurs ▪ Cats, camels, rabbits, ferrets   Corpus The ruptured follicle fills with blood & clots hemorrhagicum Forms the corpus hemorrhagicum (CH) Granulosa cells lining CH multiply due to LH hormone Granulosa cells form a solid structure THE CORPUS LUTEUM (CL) Corpus luteum “Yellow body” Produces progestins (progesterone) Progesterone is the hormone of pregnancy A fertilized ovum tells the CL to stick around, otherwise it degenerates  Follicular atresia ▪ Follicles partially develop during the cycle but never were ovulated ▪ These follicles degenerate ▪ Process is known as follicular atresia  Oviducts (“Fallopian tubes” or “Uterine tubes”)  ▪ Oviduct is the site of fertilization ▪ Tips of uterine horns (infundibulum) catch the ovum and carry it down the oviduct ▪ Fimbriae are muscular finger-like projections ▪ They feel along the ovary to the location of the follicle so catching the ovum is successful ▪ Oviduct delivers the egg to the uterus ▪ Lined with cilia ▪ Walls are made of smooth muscle fibers ▪ Spermatozoa are present in the oviduct   Uterus ▪ Functions ▪ Womb, grows and protects fetus ▪ Pushes the fetus out during birth ▪ Forms the placenta ▪ Y shaped in most domestic animals (body + uterine horns) ▪ Endometrium – inner layer, simple columnar epithelium and simple tubular glands ▪ Myometrium – thickest layer, smooth muscle This Ph oto by Unknown Author is licensed und er CC BY ▪ Perimetrium – outmost layer, covered in visceral peritoneum   Cervix ▪ Smooth muscle sphincter ▪ Located between the body of the uterus and the vagina ▪ Protects the uterus & fetus from infection from outside world ▪ Closed tightly except during ▪ Estrus (heat) ▪ Parturition (birth) This Ph oto by Unknown Author is licensed und er CC BY  Vagina ▪ Vagina is the tube that receives the penis during breeding ▪ Also the birth canal during parturition ▪ Lined with mucous glands  Vulva  ▪ External portion of the female reproductive system ▪ 1) Vestibule ▪ The entrance to the vagina ▪ Urethra open on the ventral portion of the vestibule ▪ 2) Clitoris ▪ Located on the floor of the vestibule, closer to the exterior ▪ Equivalent to the male penis ▪ 2 roots, glandular tissue, erectile tissue ▪ 3) Labia ▪ Lips, forms external boundary of the vulva   Estrus vs. Estrus “heat” Estrous cycle The period when the female is receptive to the male Physical and behavioral changes Estrous The time from the beginning of one heat to the beginning of the next heat Controlled by FSH & LH FSH: Stimulate ova to mature (FSH) FSH: Stimulate cells to produce estrogen to bring about estrus LH: Triggers ovulation LH: Stimulates production of the corpus luteum, which produces progestins   Estrous cycle Polyestrous Cycle continuously repeats throughout the year if not bred intervals Cycle continuously repeats Seasonally at certain times of the year if not bred polyestrous Cats, horses, sheep 2 cycles per year (spring & Diestrous fall) Dogs 1 cycle per year Monoestrous Foxes & mink   Stages of Estrous cycle ▪ 4 stages ▪ Proestrus ▪ Estrus ▪ Metestrus ▪ Diestrus ▪ Anestrus – stage between breeding seasons   Proestrus ▪ Period of follicular development in the ovary ▪ Estrogen begins to be produced and increases as follicle grows ▪ Physical changes during proestrus ▪ Thickening and development of the linings of the repro tract ▪ Oviduct ▪ Uterus ▪ Vagina ▪ Cornification of the vaginal epithelia (keratinization) ▪ Can be used to determine stage of estrous   Estrus ▪ Heat period ▪ Peak estrogen levels ▪ Physical and behavioral changes signal to the male ▪ Ovulation occurs near the end of This Ph oto by Unknown Author is licensed und er CC BY-SA-NC estrus in most species ▪ Except induced ovulators  Metestrus ▪ Period after ovulation ▪ Corpus luteum develops under influence of LH ▪ The CL produces progesterone ▪ Physical changes of metestrus ▪ CL grows ▪ Progesterone inhibits follicular development ▪ Uterus lining grows in preparation of implantation of embryo ▪ Loss of cornified epithelium in vagina ▪ Dogs & cats don’t have a discernable metestrus  Diestrus ▪ Active luteal phase ▪ CL is maximum in size with highest production of progesterone ▪ If embryo implants, it sends a signal for CL to continue ▪ If no pregnancy, the CL degenerates ▪ After diestrus, either proestrus occurs or anestrus ▪ Pseudocyesis – false pregnancy ▪ Prolonged diestrus,common in bitches   Anestrus ▪ Period of temporary ovarian inactivity ▪ Animals are not capable of breeding/pregnancy during anestrus This Ph oto by Unknown Author is licensed und er CC BY-NC-ND   Clinical relevance: Pyometra ▪ Pyometra is an infection of the uterus. Pus fills the uterus. ▪ Clinical signs: PU/PD, anorexia, vomiting, vulvar discharge (if open pyometra), enlarged abdomen ▪ Diagnosis: Abdominal ultrasound or radiography ▪ Treatment: OVH ▪ Without treatment? Death https://www.pdsa.org.uk/pet-help-and-advice/pet-health- ▪ Recommendation: spay your dogs! hub/conditions/pyometra-infected-womb-in-dogs   The end