Female repro anatomy Flashcards
Location of the ovaries?
Lie adjacent to proximal ends of uterine horns
Are attached to broad ligament
Two functions of the ovaries
Production of gametes and hormones
Ovary structure
Outer cortex:
- Collagen fibres provide support (ovarian stroma)
- Ovarian parenchyma (follicles and various interstitial cell types)
Central medulla:
- Blood vessels
- Lymphatics
- Nerves
- Connective tissue
Follicle contains
1 oocyte + surrounding follicular cells
Stages of follicular development
- Primordial follicle
- Primary follicle
- Secondary follicle
- Tertiary follicle
- Antral follicle
- Ovulating follicle
- Corpus luteum
- Corpus albicans
Primordial follicles
One layer of flattened follicular cells surrounding oocyte
Form before the female is born - further development does not occur until puberty
Primary follicle
Onset of follicular maturation (develop as soon as the animal starts to be reproductive)
Flattened cells now form cubodial epithelium (also called granulosa cells)
Zona pellucida becomes visible
Zona pellucida
Glycoprotein coat surrounding oocyte designed to prevent polyspermy
Secondary follicle
Follicles with straified epithelium, enclosing oocytes with a distinct zona pellucida
Small fluid-filled spaces become visible between granulosa cells
These spaces will fuse to form antrum
Thecal cells: epitheliod cells outside follicle intermeshed with stroma - form a wall around follicle - start to produce oestrogen - stimulates follicle to keep growing
Tertiary follicle
Follicular epithelium produces fluid
Eventually forms an antrum
Antrum follicle
Increases further in size
Oocyte floats in antrum
~12h before ovulation a small ‘bump’ forms on surface of the follicle (stigma)
Follicle ruptures at stigma and oocyte released
Ovulating follicle
Follicle ruptures at stigma and oocyte is released
Emptied follicle filled with blood
Wall of follicle collapses & folds in
Cell lutenization and proliferation occurs
(blood in follicle only lasts about 12 hours)
Corpus Luteum
Vascularisation
Cell differentiation
Endocrine organ - progesterone
Very large relative to ovary
- If the egg is fertilized corpus luteum remains and produces progesterone to support pregnancy
Corpus Albicans
Scar from old corpus luteum
The wall of the entire female genital tract consists of 3 concentric layers:
- Mucosal tunic (inner tunic)
- Muscular tunic (middle tunic)
- Serosal (outer tunic)
Mucosal tunic (female repro tract wall)
Inner tunic
Forms longitudinal folds in oviduct and non-gravid uterus
Muscular tunic (female repro tract wall)
Middle tunic
Two muscle layers, inner circular and outer longitudinal layer separated by a highly vascular layer
- help move sperm and ova via muscle contraction
Serosal tunic (female repro tract wall)
Outer tunic -
composed of peritoneum, covering surface of oviduct
Infundibulum
- Thin-walled funnel cranial extremity of oviduct
- Free-edge of funnel ragged & tags (fimbriae) come into contact with ovary
- Captures ovum
- Finger-like projections catch the egg
Uterine tube/ Oviduct
- Narrow and flexuous tube
- Fertilisation occurs in oviduct
- Joins apex of horn of uterus at uterotubal junction
Uterus
Y-shaped (bicornuate) with paired uterine horns in domestic species
Consists of:
- Uterine horns
- Body (usually quite small)
- Cervix (thick walled)
3 layers lining uterus:
- Endometrium (mucosal layer) - Uterine glands present - provide nourishment for early embryo
2 .Myometrium (fibromuscular layer)
- Serosal layer
In ruminants, the endometrium of the uterus is marked with numerous permanent elevations called….
Caruncles
- mark the sites of embryonic attachment
Function of the cervix
Protects the uterus from infection
The cervix can seal off the uterus in two ways:
- Cervical wall - very muscular and capable of contraction
2. Mucous secreting cells - produce material that hardens and seals off the uterus
Vagina
the section of the reproductive tract from the cervix to the entrance of the urethra (urethral orifice)
Long, thin-walled and distensible in length and width (flexibility needed for giving birth)
Fornix
ring-like space (intrusion of cervix into vagina)
Vestibule
extends from urethral orifice to external vulva
Vestibule walls are less elastic than vagina and come together at rest
May be a transverse mucosal ridge (hymen) at junction between vagina and vestibule
Vulva consists of:
- 2 laterally positioned labia (lips – skin folds – protects entrance)
- Bordering a slit-like opening: vulval cleft
Genital system suspended from dorsolateral wall by
Paired broad ligaments
Areas of species differentiation of the uterus
- Presence of two uterine horns in most domestic animals (not humans/primates)
- Length of uterine horns
- Type of placentation
- Cervix: internal structure
Uterine glands produce
Uterine milk - mucus, lipids, glycogen, proteins
Placenta
combination of foetal & maternal tissues for exchange of materials between mother & foetus
Transient organ of pregnancy
What is the foetal component of the placenta derived from?
Chorion
What is the maternal component of the placenta derived from?
Modifications of uterine endometrium
What are the functions of the placenta?
- Provides metabolic requirements of foetus
- Removes waste from foetal circulation
- Prevents mixing of foetal and maternal blood
- Associated with hormone production
List the extraembryonic membranes?
- Chorion (outermost)
- Yolk sac
- Allantois (surrounds amnion)
- Amnion (surrounds and protects the embryo)
Chorion
outermost part of the extra-embryonic membrane (epithelial layer) critical role in the attachment to the wall of the mother’s endometrium
Yolk sac
Storage of nutrients
In most domestic species the yolk sac is only there during early stages of pregnancy
Allantois
Membrane is still growing during early pregnancy from hindgut of foetus
Allantoic cavity will fill with allantoic fluids
Amnion
Surrounds the foetus
Serves as a cushion
Amniotic fluid in cavity protects the foetus from trauma
Chorioallantoic membrane
Chorion fused to allantois
Forms the foetal component of the permanent placenta in all domestic species
What is the functional component of the foetal placenta?
Chorionic villus - projections which interdigitate with villi on the endometrium
Placentation
Attachment of the outer-most foetal membrane to the endometrium
Brings the maternal and foetal blood streams as close together as possible
(there is NO DIRECT CONTACT between maternal & foetal blood)
How does blood enter and leave the foetus?
Via the umbilical cord
Urachus
The part of the umbilical cord that links the allatoic cavity and the urinary bladder
Urachus
The part of the umbilical cord that links the allatoic cavity and the urinary bladder
What type of placenta does a dog have?
Zonary placenta
What type of placenta does a horse have?
Diffuse placenta
What type of placenta do ruminants have?
Cotyledonary placenta
Cotyledonary placenta
Found in ruminants
Has uterine caruncles (mother) - round elevations on endometrial surface
Caruncles are constant in number & specifically located
Caruncles increase in size as pregnancy develops
Only site of attachement:
Caruncle (maternal) + Cotyledon (foetal) = Placentome
Cotyledonary placenta
Found in ruminants
Has uterine caruncles (mother) - round elevations on endometrial surface
Caruncles are constant in number & specifically located
Caruncles increase in size as pregnancy develops
Diffuse placenta
Found in sow and horse
Contains Areolae
- Circular spaces between chorion surface and endometrium, into which uterine milk is released
Areolae increase surface area and allow for more diffusion
Attachment to endometrium occurs over most of the chorioallantois
What do mammary glands develop from?
Sweat glands
Functions of mammary glands
Nourish offspring
deliver maternal antibodies to newborn offspring (in colostrum)
What is the functional unit of mammary glands?
Mammary epithelial cells which secrete milk
Papillary duct
Teat canal
The pathway of milk through the mammary gland
Glandular cells (epithelial cells) - secrete milk
Contraction of myoepithelial cells (via oxytocin) - squeezes milk into intralobular ducts
Interlobular ducts
Lactiferous ducts
Lactiferous sinus (divided into 2 parts: Gland sinus & teat sinus)
Papillary duct (teat canal)
Milk exits through Teat orifice
Zonary placenta
o Found in carnivores
o Attachment occurs along a central band surrounding the embryo
o Maternal epithelial & connective tissue layers are destroyed during implantation – via invasion of villi into uterus wall
