Function of the mesovarium
Attaches the ovaries to the posterior surface of the broad ligament
Function of the suspensory ligaments
Attaches the superior pole of the ovaries to the pelvic wall and carries ovarian vessels and nerves
Function of the ovarian ligaments
Attaches the inferior pole of the ovaries to the uterus
When does a primary oocyte become a secondary oocyte
Meiosis I is completed at ovulation to form the secondary oocyte This will only happen to one dominant follicle (unless its twins)
When does a primary follicle become a secondary follicle
When fluid begins to fill the follicle
When are the number of oocyte at their peak
2-5 months gestation
Phase of meiosis that oocytes are arrested in at birth
Prophase I Once ovulated, they will enter meiosis II and remain in metaphase II until they are fertilized
Products of meiosis in oogonia
1 ovum and 2-3 polar bodies
Histology of primordial follicles
Surrounded by simple squamous cells (flattened looking cells) Contain balbiani body —> all the organelles in the cell are pushed to one sideContain annulate lamellae —> stacking of membranes
Histology of primary follicles
Surrounded by simple cuboidal cells Will start out as unilaminar (single layer of cuboidal cells) and then become multilaminar (more than one layer of cuboidal cells) —> cells are referred to as granulosa cells once they are mulilaminar —> granulosa layer is avascular and separated from surrounding cells by a basal lamina Oocyte begins to develop and contain cortical granules, balbiani body disperses Nucleus is still arrested in meiosis I (condensed chromatin) Zona pellucida is secreted by oocytes and is between the oocyte and the granulosa cells
Function of granulosa cells
Have FSH receptorsConvert androgens (made by thecal cells) to estrogens via aromatase Remain in contact with the oocyte through long processes and provides nutrients, signals for growth and maturation Later in ovulation, granulosa cells of the dominant follicle will eventually become responsive to both LH and FSH
Theca interna
Begin to present around a mulilaminar follicle Highly vascular layer of cuboidal secretory cells that respond to LH to produce androgens Cells begin as squamous cells than then turn into cuboidal cells as they become more active
Theca externa
Outer layer to theca interna A CT layer with smooth muscle and collagen bundles Smooth mm is involved in ovulation —> contraction will help propel the oocyte out of the ovaries
Histology of theca interna cells
Have features typical of steroid secreting cells (sER, mitochondria, lipid droplets)
Histology of secondary (antral) follicles
Appearance of fluid filled cavities (follicular antrum) —> will eventually lead to separation of the granulosa layer Still contains a primary oocyte Call-exner bodies (precipitations of fluid) may be seen in the granulosa layer
Oocyte maturation inhibiting (OMI) factor
Secreted by granulosa cells into antral fluid in the secondary follicle Inhibits further growth of the oocyte
Factors required for secondary follicle growth
FSH, EGF, IGF1 and calcium
Corona radiata
Inner layer of granulosa cells (surrounding the oocyte) after the secondary follicle antrum fills with enough fluid to seperate the granulosa layer
Cumulus oophorus
A mound of granulosa cells that attach the corona radiata to the rest of the granulosa layer
Histology of a graafian (mature) follicle
Follicle greater than 10mmExpanded antrum Thinner appearing granulosa layer More prominent thecal layers
Selection of a dominant follicle
Dominant follicle secretes follicular regulatory protein —> retards the growth of other follicles Sometimes, more than one follicle will reach maturity, resulting in release of more than one ovum Drugs can stimulate follicular growth and result in maturation of more than one follicle
Factors leading to ovulation
About 24h before ovulation, LH/FSH surge prepares the dominant follicle to prepare for ovulation —> causes the primary oocyte to become a secondary oocyte Glycosaminoglycans will begin to be deposited between the oocyte-cumulus cells and the granulosa layer —> leads to fluid accumulation and increase in follicle size —> LH and FSH simulates release of proteolytic enzymes and increasing follicular size leads to proteolysis of the follicular wall (where there is decreased blood flow) —> contraction of smooth mm in the theca extrna will push fluid and the oocyte outside the ovary —> ovulation —> oocyte is now a secondary oocyte
Events in the follicle after ovulation
Granulosa cells form deep folds —> bleeding into the cavity from vessels in the theca interna forms a central clot —> corpus hemorrhagicus —> connective tissue invades the follicular cavity —> theca interna and granulosa cells change morphologically —> the structure becomes the corpus luteum —> main function is to produce progesterone in preparation for potential fertilization
Process of fertilization
1. Final capacitation of sperm occurs prior to binding to receptors in the zona pellucida2. Binding triggers acrosome reaction —> release of acrosomal enzymes 3. Degradation of components of the zona pellucida allows sperm to penetrate 4. Fusion of sperm membrane and entry into ovum —> discharge of cortical granules that were being produced by the oocyte; oocyte cell membrane (oolemma) becomes impermeable to other sperm due to depolarizaiton; perivitelline barrier forms in zona pellucida and sperm binding receptors degrade
Factors that maintain the corpus luteum during pregnancy
Ovarian luteotropins: estrogens, IGF1 and IGF2Endocrine luteotropins: hCG*, prolactin, insulin
Maintenance of the corpus luteum during menstruation
Remains active for 14 days and then degenerates —> corpus albicans
Histology of the corpus luteum
Formerly granulosa cells become granulosa lutein cells —> secretion of progesterone Formerly theca interna cells become theca lutein cells and stain deeply, are small, and located in the periphery —> secretion of estrogen
Histology of corpus albicans
No more nuclei can be seen Sometimes, a thickening of the basement membrane between the granulosa and thecal cell layer will remain —> glassy membrane
Atresia
Occurs at any stage of follicular maturation; mediated by apoptosis of the granulosa cells Primary follicles: oocyte degenerates —> breakdown of granulosa cells Larger follicles: cessation of follicular cell mitosis —> follicular wall degenerates —> phagocytes digest the oocyte and zona pellucida —> follicle becomes invaded by connective tissue cells
Interstitial glands of the ovary
Luteal cells remaining after atresia that produce steroid hormones Occur in the first year of life and during early puberty —> involute at menarche when there is an increase in follicular atresia
Ovarian hilar cells
Found in the hilum and contain Reinke crystals Analogous to leydig cells Respond to hormonal changes and may secrete androgens
Predominant hormone of the proliferative phase of menstruation
Estrogen
Predominant hormone of the secretory phase of menstruation
Progesterone
Regulators of the ovarian cycle
LH and FSH Surge ~24h before ovulation
Function of the uterine (fallopian) tubes
To transmit the ovum form the ovaries to the uterus Provides a suitable environment for fertilization and initial development
4 regions of the uterine tube
Infundibulum Ampulla Isthmus Intramural
Mucosal layer of the uterine tube
Most pronounced in the ampulla Exhibits prominent folds Lined by simple columnar epithelia with two cell types: peg cells (non ciliated) and ciliated cells
Function of peg cells in the uterine tube
Facilitates sperm capacitation Provides nutrients for ovum and early embryo Inhibits movement of microorganisms to the oviduct and peritoneal cavity Growth is stimulated by progesterone
Function of ciliated cells in the uterine tube
Cilia beat toward the uterus to propel the ovum or early embryo to the uterus Ciliogenesis is stimulated by estrogen
Muscularis layer of the uterine tube
Consists of an inner thick circular layer and an outer longitudinal layer of muscle —> peristalsis propels the ovum/embryo to the uterus Inner layer becomes thinner as the tube nears the isthmus Contain blood vessels (esp. veins) that constrict during ovulation and engorge —> leads to bending of the infundibulum and ovary to allow oocyte to enter the tube more easily
Histology of the isthmus
Thinner epithelium Less prominent mucosal layer (less folds)
Function of the uterus
Environment for fetal development
Regions of the uterus
BodyFundusCervix
Layers of the uterine wall
1. Endometrium (mucosa)2. Myometrium 3. Perimetrium
Regions of the endometrium of the uterine wall
Stratum functionalis (sloughed off during menstruation)Stratum basalis (regenerative source of stratum functionalis) Made of simple columnar epithelium with secretory cells and ciliated cells Contains glands and lots of ground substance Lamina propria contain glands that are simple branched, tubular —> glands become very coiled during secretory phase of menstruation
Regions of the myometrium of the uterine wall
3 layers of smooth mm 1. Inner longitudinal 2. Middle circular (stratum vasculare — where all the vessels are located) 3. Outer longitudinal
Regions of the perimetrium of the uterine wall
Consists of mesothelium and CT Covers the posterior surface and part of the anterior surface Remainder of the uterus is covered by adventitia
Blood supply of the endometrium
Uterine artery —> accurate arteries —> radial branch —> 1. Small, straight arteries (supply stratum basalis) 2. Spiral arteries (supply stratum functionalis during proliferation)
Factors that contribute to uterine growth during pregnancy
1. Hypertrophy of existing muscle cells 2. Division of existing muscle cells and differentiation of musenchymal cells to become muscle cells 3. Increase in the amount of CT
Histology of the proliferative phase of menstruation
Re-epithelization of functionalis from the basalis layer Straight tubular glands Arteries become slightly coiled Glycogen accumulates in the epithelial basal cells Lamia propria is highly cellular without abundant reticular fibers
Histology of the secretory phase of menstruation
Enlarged, corkscrew shaped glands Secretory products are present in the lumen of glands (rich in glycogen) Few mitotic figures Hypertrophy of epithelia cells Lengthening and coiling of spiral arteries Edema of endometrium (fluid accumulation in the lacunae)
Histology of the menstrual phase
Decrease in glandular secretions and stroma edemaStrata functionalis begins to fall apart
Characteristics of the menstrual phase
Periodic contractions of spiral arteries leads to ischemia of stratum functionalis Continued contraction of spiral arteries causes disruption of surface epithelium and rupture of blood vessels
Contents of menstrual flow
Blood, uterine fluid, stroma, epithelial cells
Types of cells found in the internal os and cervix
Simple columnar epithelium with glands Wall is mostly dense irregular CT except during pregnancy, it becomes more pliable due to changes in the fibrous and amorphous components
Types of cells found in the external os
Stratified squamous epithelium
Types of secretions produced in the cervical mucosa
1. Serous (during ovulation) 2. Viscous (non-ovulation and pregnancy)
Cause of nabothian cysts
Clogged cervical glands
Cervix transformation zone
Area where columnar epithelium is replaced by stratified squamous epithelium Location varies, but is close to the external os Lots of lymphocyte can be found here Location of pap smears
Cervical ectropion / cervical erosion
Transitional zone extends too far into the external os
Causes of cervical cancers
HPV (DNA virus that infects keratinocytes of skin and mucous membranes) Virus can more easily get through columnar epithelium —> cause koilocytosis (perinuclear clearing in cells)
Layers of the vaginal wall
1. Mucosa: stratified squamous epithelium, fibroelastic, richly vacularized CT 2. Mucularis: outer longitudinal continuous with that of the uterus and inner circular; a skeletal muscle sphincter is present at the vaginal opening 3. Adventitia: contains an extensive venous and nerve plexus
Characteristics of vaginal epithelium
Stratified squamous; non-keratinizedSurface is lubricated by mucus secretions form the cervical glands and vestibular glands in the vaginal vestibule During proliferative phase under estrogen influence —> epithelial cells accumulate glycogen to maintain flora
Regions of the vaginal lamina propria
Outer, highly vascular loose CT Deeper region: more dense with thin walled veins = erectile tissue Few sensory nerve ending Diffuse lymphatics and nodules (increase at menstruation)
Regions of the vaginal adventitia
Inner dense CT layer with numerous elastic fibers Outer loose CT layer with numerous blood and lymphatic vessels as well as nerves
Histology of labia majora
Stratified squamous epithelium Sebaceous glands Hair follicles
Histology of labia minora
Folds of skin that contain a core of erectile tissue No adipose tissue or hair follicles Sebaceous glands Homologous to the skin of the penis Cells have abundant melanin —> darker colored skin
Vestibule
Cleft between the labia minora that receives the vaginal and urethral openings
Histology of the vestibule
Lined with stratified squamous epithelium Lesser vestibular glands (Skene's) are present near the clitoris and around urethral opening —> mucus secreting Paired bartholin glands (homologous to male Bulbourethral glands) —> mucus secretion
Erectile bodies of the clitoris
Corpora cavernosa: surrounded by a collagenous sheath Glans clitoris is covered by thin skin that contains numerous sensory nerve endings
Mammary glands
Modified apocrine sweat glands that develop under the influence of sex hormones (ducts are stimulated by estrogen, acini are stimulated by progesterone) Consist of lobes —> each lobe is drained by one lactiferous duct (interlobular CT is dense irregular) Lobules consist of secretory acini and it's associated ducts (intralobular CT is loose)
Epithelium of the mammary glands
Intralobular ducts and lactiferous ducts: simple columnar Lactiferous sinus: stratified cuboidal Nipple opening: stratified squamous
Epidermis of the areola and nipple
Highly pigmented keratinized stratified squamous epithelium with long dermal papillae that is richly vascularized and contain free nerve endings Surrounded by dense CT
Glands of the areola and nipple
Sebaceous glands, sweat glands, glands of montgomery
Smooth mm of the nipple
Circular around the nipple Longitudinal along the long axis of the nipple Contraction is involved with milk ejection
Histology of an inactive mammary gland
Mostly ductsMore adipose tissue and CT between ducts Most sarcomas come from the intralobular loose CT
Function of estrogen in mammary glands
Stimulates growth of ducts
Function of progesterone in mammary glands
Stimulates alveoli growth
Histology of a proliferating mammary gland
Many alveoli Less fat accumulation and CT Increase in plasma cells, lymphocytes, and eosinophils
Cells of the alveolus
Cuboidal secretory cells Myoepithelial cells (respond to oxytocin)
Types of secretions of the mammary gland
1. Apocrine —> lipids 2. Merocrine —> protein
Stimulation of milk production
Stimulated by prolactin 4 days following childbirth when estrogen and progesterone levels decrease Also stimulated by handling of the newborn
Histology of mammary gland involuntion
Decrease in alveoli, fibroblasts, collagen, and elastic fibers