Cervix & Vagina normal anatomy & histology 2-25

describe the development of the vagina

forms from the fused paramesonephric ducts (superior part) and the urogenital sinus (inferior part). The mesonephric system normally regresses completely. Sometimes remnants do remain within the mesovarium and/or on the wall of the vagina or uterus (Gartner's cyst). - remnant of mesonephric duct, not fully regressed causing a cyst adjacent to vagina

illustrate the histology of endo/ectocervix

transformation zone or squamocolumnar junction

what can occur if the mammary line does not fully regress?

accessory nipples, ectopic mammary glands (remnants in vulva = papillary hidradenoma, extramammary paget dz)

what is the vulva?

collective external female genitalia: -Mons pubis -Labia majora -Labia minora -Clitoris -Vestibule

describe the histology of the cervix

-Ectocervix is lined with stratified squamous epithelium, just like the vagina. -Endocervix (cervical canal) is lined with simple columnar epithelium -Cervical glands abundant -Junction between these two regions is abrupt = transformation zone or squamocolumnar junction -Before puberty/post menopause location of junction within canal 1. External Os 2. Ectocervix 3. Stratified squamous ep. 4. Endocervix 5. Cervical canal 6. Cervical glands 7. Transformation zone

describe vulva normal histology

All structures lined with stratified squamous epithelium Tissue of labia majora and minor are abundant with large sebaceous glands Vestibule contains numerous small glands - Lesser vestibular glands: near clitoris - Greater vestibular glands *(Bartholin's glands*) -- homologous to bulbourethral glands in males - In lateral wall of vestibule: secrete lubricating mucous

describe the pathogenesis of vaginal adenosis

During embryonic development simple columnar epithelium extends from endocervix to upper part of vagina. This is normally replaced by stratified squamous epithelium that extends from the UG sinus upwards Remnants of the simple columnar epithelium may persist into adulthood causing the adenosis

describe the development of the mammary line

Mammary glands originate from longitudinal thickening that runs between limb buds (aka milk line) Glands develop as thickenings that canalize and appear similar to apocrine sweat glands Normally, the ridge disappears everywhere quickly, except in the pectoral region

describe the histology of the vagina

Mucosal layer- lines inside lumen of vagina. Outside is (non-keratinized) stratified squamous epithelium. Underlying CT projects into epithelium -There are no glands within the lumen of the vaginal—most lubrication comes from the cervical and vestibular glands. -Lamina propria with two regions: one directly below epithelium, another deeper more dense layer containing numerous blood vessels -Many lymphocytes in upper layer of lamina propria, number increases during menstruation Muscular layer: organized into outer longitudinal and inner circular layers.