ERS22 Histology Of Female Reproductive System Flashcards
Functional anatomy of female reproductive system
Internal genitalia (Ovaries + Reproductive tracts)
- Ovaries
- produce female germ cells / eggs
- produce sex hormones
Reproductive tracts
- Uterine tube
- sites for fertilisation
- transport embryo to uterus - Uterus
- harbours fertilised egg during gestation (maintain conceptus)
- provide nutrition + protection to fetus - Vagina
- connect internal genitalia with exterior - Accessory glands
- **Greater vestibular gland
- **Minor vestibular glands - External genitalia
- collectively aka Vulva: Labia majora + Labia minor + Mons pubis + Clitoris
- protection of internal genital organs + allow sperm to enter body
Ovary: Structure + Function
House maturing ovum
- Cortex
- highly cellular outer layer
- ***Ovarian follicles containing Oocytes (various stages of development) —> embedded in CT stroma (cellular rich CT)
- no distinct boundary with Medulla - Medulla
- richly vascularised loose CT —> ***transport hormones in blood vessels
- nerves
- lymphatics
- no distinct boundary with Cortex - Tunica albuginea
- dense, irregular CT capsule —> whitish colour
- protect ovary
- covered by Germinal epithelium - Germinal epithelium
- **Simple cuboidal —> continuous with **Simple squamous mesothelial cells of outer peritoneum
- modified ***Mesothelium
- sitting on BM - Suspensory ligament
- Ovarian vessels - Ovarian ligament
- remnant of Gubernaculum —> connect Ovary to Uterus —> ***continuous with Round ligament of uterus
Timeline of development of female gonads
Before birth:
- Oocytes in ***Prophase 1 until menarche
- Incompletely developed reproductive organs —> remain in rest until ***Gonadotropic hormones (LH, FSH) by Pituitary gland —> signal initiation of puberty
After menarche:
- Cyclic changes of reproductive system
- Menstrual cycle repeated each month throughout reproductive years unless interrupted by pregnancy
After menopause:
- Menstrual cycle becomes irregular —> cease
- Slow involution of ovaries
Follicular growth
Begins in embryo
—> Stop
—> Restart in puberty
Follicles:
- Granulosa cells: surrounding follicle (initially 1 layer —> few layers later)
- Theca cells: differentiated from Fibroblasts (from Stroma outside)
- Antrum: fluid accumulation between cells
3 phases:
- Follicular phase
- follicle mature - Ovulation phase
- mature follicle rupture —> expel egg - Luteal phase
- Corpus luteum: temporary endocrine gland, remnants of follicle —> degenerate into Corpus albicans
Ovarian cycle
Primordial follicle (Oocyte + Granulosa cells (single layer))
—> Primary follicle (Granulosa cells (large cuboidal then enlarges —> > 1 layer) + Zona pellucida form around oocyte)
—> Secondary follicle (Fluid-filled vesicles formed among Granulosa cells + Theca cells formation) (Theca: External + Internal)
—> Mature follicles (Antrum: fluid-filled vesicles fused together): Oocyte located within Cumulus mass
—> Oocyte released during ovulation along with some surrounding Granulosa cells (in Cumulus mass) called ***Corona radiata
After ovulation:
Granulosa cells divide + enlarge
—> Corpus luteum
—> Corpus albicans (if degenerate)
Atretic follicles:
5-7 million Oogonia (before birth)
—> 1 million Oogonia surrounded by Follicle (at birth)
—> 400,000 Primary follicles (menarche)
—> 450 oocytes released (throughout reproductive life)
—> Many follicles degenerate before reaching maturation
—> undergo atresia at any stage
—> phagocytosed by macrophages
—> space occupied by fibroblast —> collagenous scar
Reproductive tracts: Structure + Function
Uterine tube:
- Transport fertilised egg to uterus (Fimbria of ciliated epithelium + Muscular wall of uterine tube)
- Transport spermatozoa to reach primary oocyte
- Site of fertilisation (Ampulla)
- Produce Trophic substance / Nutrition for oocyte / conceptus
- Extensive mucosal folds covered with **Ciliated Simple Columnar epithelium + **peg cells (secretory) —> produce nutritious mucus for suitable environment for fertilisation
Uterus:
- House + Nourish embryo during pregnancy
- Perimetrium
- Myometrium —> expel baby during labour
- Endometrium —> implantation of embryo
- ***Stratum Basalis —> remaining residual cells that proliferate to produce new mucosa cells i.e. Functionalis
- ***Stratum Functionalis —> mucosa of uterus: shed with menstrual flow —> menstruation after 14 days of ovulation
Vagina (muscular canal):
- Receives penis during copulation
- Menstrual flow
- Birth canal
- Non-keratinised Stratified squamous epithelium
***Epithelial lining of Reproductive tracts
- Uterine tube —> Simple columnar, ciliated / non-ciliated (peg) cells
- Uterus —> Simple columnar, with ciliated cells
- Cervix
—> Uteral part: Tall columnar, mucus secreting
—> ***“Transformation zone”
—> Vaginal part: Non-keratinised Stratified squamous - Vagina —> Non-keratinised Stratified squamous
Uterine tubes
Oviducts / Fallopian tubes
- ***Mucosal folds visible on entire length
- ↓ progressively in height + complexity towards uterus
- Intramural portion
- penetrates uterine wall
- open into uterine cavity
- thin muscularis - Isthmus
- short, narrow
- joins each uterine tube to uterus - Ampulla
- **longest, widest
- **site of fertilisation
- ***thick muscularis - Infundibulum
- opens into peritoneal cavity
- Fimbria —> close to Ovary surface —> favour transport of ovulated oocyte into uterine tube
Histology of Uterine tubes
Lumen surrounded by 3 concentric layers
- Mucosa
- mucosal folds greatly ↑ SA
- line lumen
- **Simple columnar
- **Ciliated cells: Cilia beats towards Uterus
- ***Non-ciliated (peg) cells (fewer): Secretory, viscous fluid —> favourable environment
- rest on Basal lamina
- inner Lamina propria (loose CT) - Muscularis
- Inner circular + Outer longitudinal smooth muscle —> peristaltic contraction along oviduct —> movement of sperm + oocyte
- indistinct 2 layer —> vary in thickness (thin in Intramural portion, thick in Ampulla)
- ***Muscularis of Intramural portion merges with Mucosal layer of Uterus - Adventitia
- Outer loose CT
- Mesothelial cells
Fertilisation
- Oocyte must be fertilised within 12-24 hours after ovulation
- Sperm remain ability to fertilise for a few days in female reproductive tract (most reach Ampulla within 3 hours)
Attachments of sperm:
- ***stimulus for oocyte to complete 2nd meiosis
—> Corona radiata retained for some time during passage of oocyte / zygote to Uterine tube
—> fertilised oocyte: Zygote
—> 1st mitotic division (beginning of Embryonic development)
—> Conceptus slowly transported out into uterus
Clinical significance:
Ectopic pregnancy:
- **Tubal pregnancy (Ampulla / Fimbria / Isthmus) —> tube may burst eventually —> **fatal haemorrhage
- problem with transportation / fertilisation
Uterus
Muscular organ
- Fundus
- entrance of uterine tube - Body
- major portion - Cervix
- narrow terminal part
- protrude into vagina
Histology of Uterus
Wall of uterus:
1. Perimetrium (outermost)
- CT
- Perimetrium of fundus / body:
—> covered by **Simple squamous epithelium of parietal peritoneum (Mesothelium)
—> continuous with **Broad ligament
- **Sympathetic ganglia + **Hypogastric plexus nerve fibres
- ***Parasympathetic fibres from Sacral splanchnic nerves
—> supply uterine blood vessels, musculature, endometrial glands
- Myometrium (intermediate)
- thickest
- 3 poorly defined layers: Interconnected smooth muscle separated by CT
- expel baby during labour
- rich blood supply, innervation, lymphatic drainage
- **Longer + Thicker inner smooth muscle during pregnancy
- **Abundant elastic fibres in peripheral myometrium during pregnancy - Endometrium (innermost)
- 2 layers: **Stratum functionalis + **Stratum basalis
- Epithelium: **Columnar secretory cells + **Ciliated cells (on BM)
- Lamina propria: thick with blood vessels + lymphatics, deep invaginations called **glands
- Blood supply: Uterine artery —> Arcuate artery —> Radial artery —> **Spiral artery (出d: supply glands in Functionalis) + ***Straight artery (入面d: supply Basalis)
- implantation of embryo
- specialised mucosa
Menstrual cycle
Cyclic changes in Functionalis layer of Endometrium (Basalis no change)
Menstrual phase (Day 1-4): - Desquamation of functional layer
Proliferative / Follicular phase (Day 4-14):
- Reepithelisation of endometrium lining
Secretory / Luteal phase (Day 14-28):
- Thickening of endometrium
Clinical relevance of Endometrium
- Menorrhagia
- abnormal menstrual bleeding - Uterine fibroid / Leiomyomas
- Benign Smooth muscle tumours
- Treatment: Uterine artery embolisation —> small embolic agent particles are injected to Uterine artery through small catheter —> embolic agents flow to fibroids —> lodge in arteries —> starve tumours - Endometriosis:
- endometrial tissue appears at ***unusual locations in lower abdomen / pelvis
- Cause: endometrial cells peel off during menstrual cycle migrate via Fallopian tube to Peritoneal cavity
- Diagnosis: Laparoscopic surgical visualisation
- Histological grade: determine stage / severity
- Epidemiology: affect puberty —> menopause (mainly between 20-30)
- Symptoms: Pelvic pain, Premenstrual bleeding
Histology of Cervix (different from Body, Fundus)
- Cervical canal
- invaginate with **plicae palmate
- **Simple columnar epithelium
—> with branched mucous secreting glands (similar to Goblets cells in respiratory epithelium)
—> produce cervical mucus (watery during proliferative phase, viscous during secretory phase) - Cervical Os
- open into vagina
- ***Non-keratinised Stratified squamous epithelium
