Female reproductive tract Flashcards
Female reproductive tract
Ligaments • Ovaries (x2) • Oviducts (x2) • Uterus – horns, body & cervix • Vagina • Vestibule • Vulva
Ligaments
- Broad ligaments: • Mesometrium
- Mesovarium • Mesosalpinx
- Proper ligament of the ovary (O to H)
- Suspensory ligament of the ovary (O to wall)
- Round ligament of the uterus
Ovaries
Ovaries
• Produce the female sex cells – Ova (oogenesis)
• Paired organs located in the dorsal abdominal cavity caudal to the kidneys
• Oestrogen and progesterone
• Attached to various areas of the abdomen via ligaments (mesovarium, mesosalpinx, suspensory ligament)
Ovarian artery (branch of the aorta and follows the suspensory ligament to the ovary) • Ovary + uterine tube enclosed in a section of visceral peritoneum known as the mesovarium • Part of the mesovarium forms a pocket like structure known as the ovarian bursa which completely covers the ovary
Ovarian cycle
- Development of ovum (egg) , ovulation, formation of corpus luteum (CL) , and degeneration of un- ripened follicles and CL
- Influenced by follicle stimulating hormone (FSH) and luteinizing hormone (LH)
Oviduct
(Uterine Tube)
• Constructed of smooth muscle
• Ciliated columnar epithelium
• Muscle contractions (peristalsis) and cilia movements guide ovum toward the uterus
• Fertilization→Isthmus
• Open end of the oviduct has modified finger-like processes that ‘catch’ the ova (Infundibulum with finger-like projections are known as Fimbriae
Uterus (Uterine Horns)
Hollow ‘Y’ shaped structure • Body
• Two uterine horns
• Wall of smooth muscle (myometrium) with an inner layer (endometrium)
The two uterine horns come together at the neck which forms a continuous section of uterus known as the body which then leads to the base of the uterus called the cervix
Cervix
- Short, thick walled muscular sphincter between the body of the uterus and the vagina
- Controls access to the lumen of the uterus from the vagina
- Normally tightly closed, except during estrus and parturition
- Relaxes to allow passage of sperm or foetuses
- During pregnancy it is blocked by a mucoid plug which detaches during parturition (labour)
Vagina
- highly dilatable muscular tube caudally from the cervix, leads to the vestibule
Vestibule
is extremely muscular and is thought by some to contribute to the ‘tie’ seen in dogs during mating. The urethra opens on its floor
vulva
The vulva marks the external opening of the urogenital tract. It consists of folds of skin known as the labia
Oestrous
Pertaining to the whole cycle
Oestrus
Pertaining to part of the cycle
Monoestrus
animal that have one oestrous cycle
Polyestrous
animals that cycle continuously throughout the year if
they are not pregnant (cattle and swine)
Seasonally polyestrous
animals with seasonal variations in oestrous cycles (horse, sheep, cat)
The oestrous cycle of the bitch
Acronym = POMDA
Pro-oestrus • Oestrus • Metoestrus • Dioestrus • Anoestrus
Pro-oestrus
The period during which the follicles in the ovary enlarge and become mature
Oestrus
When the follicles rupture and the ova are released (ovulation)
Metoestrus
The period when the corpus luteum starts to form at the site of the ruptured follicle
Dioestrus
When the corpus luteum is established or if the ova have been fertilised = pregnancy
Anoestrus
Period where there is no ovarian activity
Luteinising hormone
(LH) pathway
Graaf follicle causing ovulation> CL forms
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PROGESTERONE: Maintains pregnancy, seals uterus, mammary gland development and RELAXIN: Lig/muscular relaxation end pregnancy
Follicle stimulating hormone
FSH pathway
Graaf follicle \/ OESTROGEN \/ Pro-oestrus signs
(Oestrogens) Oestradiol
Prepare genital tract for reception of fertilised eggs
Progesterone
Essential for maintenance of pregnancy. Produced by the CL (after ovulation + placenta)
Relaxin
Relaxation of ligaments around birth canal. Late pregnancy, produced by the CL
Pseudocyesis (pseudopregnancy or false pregnancy)
Corpus luteum may prolong the production of progesterone and develop a false pregnancy
Signs include:
• Mammary gland enlargement • Milk production
• Nest making
The ewe
- (short day) seasonally polyestrus, polytocous
* 16-17 day cycle
Cattle
Polyestrous, monotocous • 20 day cycles
Mare
- (long day) seasonal polyestrous, monotocous
* 21 day cycles
Oestrus cycle in the queen
• Seasonally polyoestrous
• Long day breeders with a period of anoestrus beginning in late
autumn & resumption of reproductive activity as daylight increases
• Some cats have regular oestrous cycles lasting about 3 weeks, but others show no regular pattern.
• Duration of oestrus is 7-10 days regardless of mating.
• Induced ovulators - mating triggers ovulation
• Mating causes release of LH from the anterior pituitary
• Normally need multiple matings to achieve adequate LH release
