CVM 710 27: Female Repro

Female Reproductive System

• Ovaries

• Uterine tubes

• Uterine horns

• Uterine body

• Cervix

• Vagina

• Vestibule

Broad ligament

• Made up of mesenteries

  • Mesometrium

  • Mesosalpinx

  • Mesovarium

Mesometrium

• Uterine horn

• Uterine body

• Cervix

• Cranial vagina

Mesosalpinx

Uterine tube

Mesovarium

Ovary

Ovary

• Flattened, firm, ellipsoidal

• Suspended by mesovarium

Location of ovaries

• Dorsal part of abdomen, close to the caudal poles of the kidneys

• Right ovary more cranial than the left (similar to kidneys)

Best way to remove ovaries

• Find left ovary (easier to remove since it is more caudal), then follow uterus to right ovary

  • Makes it easier to avoid removing kidneys or ligating ureters

Functions of ovary

• Gamete production (exocrine)

• Endocrine gland (estrogen, progesterone, androgens, etc)

Structure of ovary (in most species)

• Outer cortex

  • Follicles with oocytes

  • Tunica albuginea

• Inner medulla

• Hilus

Ovaries in horses

• Flipped order:

  • Outer medulla

  • Inner cortex (still has oocytes)

• Ovulation fossa: permits oocytes to be ovulated from center of ovary

Ovarian structures

• Follicles (produce estrogen)

• Corpus hemorrhagicum (CH)

  • Follicle post ovulation, forms a bloody body or CH form

• Corpus luteum (CL)

  • Produce progestone (used to maintain pregnancy)

  • Formed from CH after a few days; bloody body is remodeled into bright yellow structure

• Corpus albicans

  • CL goes through regression and starts breaking down, forms a scar/white body on the ovary

Ovulation in felines

• Seasonally polyestrous

  • Long-day breeder

• Induced ovulators (have to undergo copulation to ovulate, which is triggered by barbs on cat penis)

Ovulation in canines

• Monoestrous

• 1-4 estrous cycles per year

  • Typically only 2 per year

• Spontaneous ovulators

Suspensory ligament of ovary

• Thickened free/cranial edge of the mesovarium that attaches the cranial pole of the ovary to the dorsal body wall

• Needs to be strummed / broken down in order to exteriorize the ovary during a spay

• Very important clinically

Proper ligament of ovary

• Attaches caudal pole of ovary to uterine horn

• Keeps ovary in place and makes sure it doesn't float in abdomen

Round ligament of uterus

• Thickening of mesometrium that passes down the inguinal canal

• Similar to spermatic cord in males

Blood supply of ovaries

• Ovarian artery

  • Branch of descending/abdominal aorta

Where does left ovarian vein drain into?

Left renal vein

Where does right ovarian vein drain into?

Caudal vena cava

Uterine tubes

• Three segments:

  • Infundibulum

  • Ampulla

  • Isthmus

• Suspended by mesosalpinx

• Blood supply: Ovarian artery

Infundibulum

• Funnel-like structure

• Fimbriae (“catcher’s mitt)

  • Finger-like structures around the edge

• Abdominal ostium

Ampulla

Site of fertilization

Isthmus

• Terminal section

• Uterotubal juction: “functional” closure to uterus

• Forms a papilla in dogs, cats, and horses

Ovarian bursa

Infundibulum forms bursae in certain species

• Cats: ovary exposed

• Dogs: ovary encased in substantial bursa

Uterus

• Bicornuate (two uterine horns)

  • Internal and external bifurcation of horns

  • Puppies implant in uterine horns (unlike humans)

• Short uterine body

• Cervix

• Suspended by mesometrium

  • Round ligament of uterus

    • Association with the vaginal process

Layers of the uterine wall

• Perimetrium (serosa)

  • Thin layer

• Myometrium

  • Outer longitudinal and inner circular smooth muscle layers

  • Allows uterus to relax and contract

• Endometrium (thick layer)

  • Submucosa and mucosa

  • Endocrine function: Makes Prostaglandin F2 alpha (kills corpus luteum)

Blood supply of Uterus

• Uterine branch of Ovarian artery

• Uterine artery (branch of Vaginal artery)

• Both anastomose within the broad ligament

Cervix

• Caudal, thick-walled segment of the uterus

• In dogs, the cervical canal is somewhat vertically oriented

• Two openings:

  • Uterine opening = internal uterine orifice/ostium

    • Between uterine body and cervix

  • Vaginal opening = external uterine orifice/ostium

    • Between cervix and vagina

Cervix (dogs)

• Dorsal median fold in the vagina extends to the cervical tubercle (vaginal portion of the cervix)

  • Pseudocervix; paracervix

• The external uterine ostium is ventral to the tubercle

Vagina

• Extends through the pelvic canal and projects caudoventrally beyond the ischiatic arch

  • Caudoventral orientation

• Fornix

• Irregular longitudinal folds

• Terminates at the level of the urethral tubercle (vestibulo-vaginal junction)

  • Hymen

• Blood supply: Vaginal artery

Fornix

• Cranial part of vagina

• Ventral to cervix in dogs

• Blind pouch that someone can get stuck in when trying to reach cervix

Longitudinal folds of vagina

Allows vagina to stretch without tearing (also can collect sperm)

Hymen

Transverse mucosal fold present at the vestibulo-vaginal junction

Vestibule

• Continues the caudoventral slope of the vagina

• Last portion of internal genitalia

• Vestibular bulbs

Cranial extent of vestibule

Urethral tubercle (at the level of the ischiatic arch)

Caudal extent of vestibule

Vulva

Vestibular bulbs

• Collection of glandular tissue

• In the floor and ventrolateral wall of vestibule

• Close to the body of the clitoris

• Homologous to bulb of the penis

• Engorges with blood and helps with tie to male

How to insert pipette or speculum

Craniodorsal insertion for vagina (just cranial would go into urethra)

External genitalia: Vulva

• Caudal-most barrier of the reproductive tract

  • Ventrally-positioned in bitch

• Two labia connected by:

  • Dorsal commissure - rounded

  • Ventral commissure - pointed

• Rima pudendi - external urogenital orifice

  • The opening between the labia / opening of the vulva

• Clitoris

Clitoris

• Homologous to penis

• Dogs:

  • Paired crura, body and glans clitoridis

• Fossa clitoridis (clitoral fossa)

  • In the floor of the vestibule, near the vulva

  • Surrounds the glans clitoridis

Ovariohysterectomy (OHE/OVH; Spay)

• Break down suspensory ligament of ovary and exteriorize ovary

• Exteriorize uterine horn

• Ligate ovarian and uterine vessels

• Transect uterus/cervix (don’t remove cervix)

• Pros: Decreases/removes chance of pyometras

• Cons:

  • Invasive procedure

  • May mistake other organs for uterus/ovaries

Ovariectomy (OE)

• Similar to OHE, but without removing the uterus

• Ligate, transect and remove ONLY the ovaries

  • Make sure no remnants left behind, can increase chance of pyometra from ovarian hormones

Laparoscopic OHE

Less invasive than celiotomy

Open pyometra

Vaginal/vulvar discharge

Closed pyometra

• No discharge

• Miore dangerous: Can rupture uterus and/or cause peritonitis

Dystocia (trouble with whelping)

• C-section

• Breed pre-dispostion

  • Bulldogs and Frenchies

Benign ovarian masses

Cysts (luteal, follicular)

Neoplasia ovarian masses

• Dysgerminoma

• Teratoma

• Granulosa cell tumor

Pregnancy in Dogs and Cats

• Litter bearers - polytocous

  • Litter size varies with species, breed, parity

    • Parity: How old the mother is / how many litters she has had

      • Older females tend to have bigger litters than younger females

• Zonary placenta

  • Each fetus has its own placenta

• Umbilical cord

  • 2 arteries

  • 1 vein

  • Urachus (fetal urethra)

• Diagnosis: Ultrasound (works earlier in pregnancy- around 28-32 days of pregnancy), radiographs (only works after 45 days of pregnancy for dogs), abdominal palpation, parturition

Zonary placenta

Location of vasculature