Female Genital Lecture 2024 PDF

Form and Function 141: HISTOLOGY Female genital system Dr Mandi Alblas & Mrs Jodie Lemphane...

Form and Function 141: HISTOLOGY Female genital system Dr Mandi Alblas & Mrs Jodie Lemphane [email protected] / [email protected] Medicine and Health Sciences | EyeNzululwazi ngezoNyango neMpilo | Geneeskunde en  4 Primary tissues All tissues consist of cells A. Epithelial tissue B. Connective tissue & extracellular matrix (ECM) D. Muscle tissue D. Nerve tissue  Outcomes: Female genital system 1. Identify and demonstrate an understanding of the stages of follicular growth (primordial, primary, secondary, mature) in the ovary. 2.Identify the regional variations in the structure of the oviduct/fallopian/uterine tube. 3.Describe the changes that occur in the ovary during the menstrual cycle. 4. Distinguish the cyclical alterations in the uterine endometrium (secretory and non-secretory phases) and understand their hormonal bases. 5.Describe the histology of the cervix and vagina. 6.Annotate simple sketches (see class notes) and understand the photomicrographs Material which is made available by way of an electronic database may be subject to certain licensing conditions. These conditions normally entail that you may only use the material for your own private study and research at the University and not for any other purpose. It is expected of you to adhere to these conditions at all times. Printed material is also only made available for class discussion, private study and research purposes. Further reproduction of such material is prohibited  Female system structure: Divided into 4 major functional components: 1.2x 3.1x uterus ovaries  maintains embryo  release eggs Secondary female Primary female reproductive reproductive organs organs 4.1x cervix  conduct sperm  neck of uterus Secondary female 2.2x reproductive organs oviducts (fallopian tubes) 5.1x vagina  conduct eggs  receives sperm  NB for Secondary female childbirth General pathway General pathway of of egg: sperm: 3 uterus 2 oviduct (fallopian tube) 4 cervix sp 1 ovary erm 5 vagina cyte oo  Ova Ovaries (Gonads) ry Primary female reproductive organs Exocrine portion – produce the ova Contain a number of follicles Each follicle encloses an ovum Endocrine portion – Function of produce ovary oestrogen & Produce ova progesterone  Ovary Covering: simple cuboidal epithelium (germinal epithelium), also called mesothelium of helicine ovary outer zone of ovarian stroma = consists of arteries ovarian follciles -enter the hilum of ovary Medulla central zone of ovarian stroma = consists of loose connective tissue & blood and lymphatic vessels along with nerve fibers Capsule: tunica Stroma albuginea Dense (atypical connective connective tissue layer tissue) between germinal layer & cortex (continuous with mesothelium of ovary) Numerous ovarian follicles (various sizes & stages of development)  Ovary: Oogenesis Oogenesis = formation & growth of ovum in ovary Germ cells migrate into ovaries during embryonic Young development Towards end of gestation = they divide by meiosis forming primary oocytes (2n) At birth up until puberty mainly primordial follicles in ovarian cortex. At birth = ± 2 million Ol oocytes d At puberty = ± 400 000 400 ovulate during reproductive life  Ovary cortex: medium magnification Ovary: overview Germinal epithelium Simple cuboidal epithelium Tunica albuginea Primordial follicle Primary follicle Secondary  Follicles in ovary (ovarianSecondary cycle) 2. 3. developing follicle Primary developing follicle 1. Primordial 4. Graaffian follicle follicle 7. Corpus albicans Ovulating follicle 6. 5. Mature corpus 8. Early corpus luteum Artretic luteum follicle  1. Primordial follicles undeveloped follicles (inactive stage) Structure: Composed of primary oocyte surrounded by single layer of flattened (squamous) granulosa cells. Zona pellucida not yet formed Development Stage: Earliest stage of follicle development, present in ovaries from birth Remain in inactive state until they receive hormone follicle-stimulating hormonal signals to grow Hormonal Influence: Minimal hormonal activity; not responsive to FSH until activated Function: Serve as reserve pool of oocytes for future maturation FSH stimulates oocyte and follicle to enlarge = (not involved in hormone granulosa production) cells start to surround oocyte = become primary follicle  2. Primary follicles Primary undeveloped follicles (active stage) developing Primary developing follicles follicles (multilaminar) (unilaminar) Structure: Composed of primary oocyte surrounded by single layer of cuboidal granulosa cells Zona pellucida begins to form around oocyte (when multilaminar) Development Stage: Follows primordial follicle (is initial stage of follicular development in response to hormonal signals) = are actively growing Hormonal Influence: Hormonal activity is low compared to later stages; but, follicles begin to to FSH (granulosa cells multiply =form zona granulosa) Function: Someoocyte Prepare primary forfollicles furtherenlarge and form maturation antrum = but & development, Surrounded by one no become secondary significant hormone follicles production occurs at this stage. Surrounded by double layer of cuboidal layer of cuboidal follicle cells follicle cells  3. Secondary follicles developing follicles (active stage) Structure: Contains primary oocyte surrounded by multiple layers of cuboidal granulosa cells Follicular Antrum (FA)(fluid-filled space) begins to develop between granulosa cells (indicate advanced state of follicle maturation). Development Stage: Secondary follicles develop from primary follicles under influence of FSH (show more active growth) luteinizing hormone Hormonal Influence: Granulosa cells start to produce oestrogen (respond to FSH & LH) - in smaller quantities compared to mature follicle Follicle is responsive to FSH but has not yet reached full maturity. Function: Crucial for maturation of oocyte and preparation for ovulation Antrum formation is essential for accumulation of follicular fluid Oocyte development: Primary oocyte is arrested in prophase I (support oocyte) of meiosis at this stage  3. Secondary follicles developing follicles (ZG) zona granulosa cells (when ±8-12 layers thick), fluid-filled spaces arise between them (FA) Spaces enlarge = form fluid-filled follicular antrum (still relative small) (O1) Primary Oocyte becomes situated eccentrically in thickened gelatinous/cloud-like area (CO) of ZG (CO) = cumulus oophorus = is crucial structure in follicle that holds oocyte in place and plays a significant role in ovulation and fertilization. (TE & TI) theca folliculi separated from Function of theca & granulosa cells granulosa cells by basement membrane together: Theca cells produce androgens = which are theca folliculi develops into 2 layers: converted to oestrogens by ova 4. Mature/Tertiary (Graaffian) follicles developed follicles Structure: Have large, well-defined antrum (significantly larger than in secondary follicle). (CO) cumulus oophorus (mound of granulosa cells) visible surrounding oocyte. Development Stage: Mature stage of follicular development = ready for ovulation (typically largest follicles in ovary and will release oocyte during ovulation) Hormonal Influence: Produce higher levels of oestrogen due to the increased number of granulosa cells Are influenced by both FSH & LH = especially in lead-up to ovulation Function: Oocyte Release development: secondary oocytePrimary oocyte undergoes for fertilisation Meiosis 1 to form secondary oocyte (haploid=n) just before ovulation  4. Mature (Graaffian) follicles developed follicles Follicle becomes mature when antrum cross section is ±1cm. (FA) Follicular antrum enlarges (ZG) zona granulosa forms even thickness layer around periphery of follicle Z T G cumulus oophorus diminishes leaving I O C oocyte (O 2) surrounded by layer R 2 several cells thick of (CR) corona radiata that remains F attached to zona granulosa by thin A bridges of cells protein Oocyte resumes meiosis in response to LH surge and supplyII,to ovum 1st meiotic progresses to metaphase completing division (ZP)justZona pellucida before ovulation = forms protective layer around ovum  Summary of difference in Follicle follicles Primordial Secondary Primary follicles Mature follicles follicles follicles Granulosa significantly more 1 layer double layer mutilayered cell shape & mutilayered squamous cells cuboidal cells cuboidal cells layers cuboidal cells Zona absent starts to form present present pellucida preparing for Activity quiescent actively developing ready for fertiisation fertiisation oocyte is arrested in metaphase II still primary Oocyte stage still primary oocyte still primary oocyte (secondary oocyte) oocyte just prior to ovulation have increased Hormone no hormonal little hormonal hormonal activity & produce highest production activity activity can produce levels of oestrogen oestrogen antrum start to large prominent Antrum size no antrum no antrum develop antrum  5. Corpus luteum After ovulation, ruptured follicle transforms into corpus luteum The corpus luteum is characterized by: Lutein Cells: enlarged granulosa & theca cells that secrete progesterone & oestrogen Vascularization: It is richly supplied with blood vessels Early corpus luteum It typically lasts for about 10 to 14 days if pregnancy does not occur Function: Play crucial role in menstrual cycle Late corpus luteum Persist longer during pregnancy (remains active for approximately 10 to 12 weeks, until the placenta takes over hormone production) Function: essential for hormone production (primarily (is yellow due to high fat concentration) progesterone) to support early pregnancy 5. Corpus luteum of menstruation Degeneration of Corpus Luteum: If no fertilization corpus luteum degenerate This process usually starts about 10 to 14 days after ovulation. Remnant of post-ovulatory blood clot (B) forms in centre Granulosa lutein cells (G) is formed by remaining granulosa cells after ovulation & is penetrated by septa S Progesterone & oestrogen levels fall Withdrawal of ovarian hormones If pregnancy does not occur, the corpus luteum causes menstruation and new cycle degenerates into the corpus albicans begins New follicles begin to grow breakdown of uterine lining= resulting in Corpus albicans Degenerated corpus luteum forms corpus albicans (collagenous scar) As corpus luteum degenerates, granulosa lutein cells (G) break down and are replaced by fibrous connective tissue (collagen), leading to formation of corpus albicans Structure small, white, fibrous scar tissue No vascularisation No cellular activity Function No hormone production Serve as remnant of corpus luteum Signifies that ovulatory phase has concluded 6. Corpus luteum of pregnancy If Fertilization Occurs: Corpus luteum CL is greatly enlarged (occupies most of ovary) Granulosa lutein cells formed by remaining granulosa cells = tend to enlarge & then calcify as pregnancy progresses Maintenance of Corpus Luteum: When ovum is fertilized, embryo begins to produce human chorionic gonadotropin (hCG) shortly after implantation. hCG signals corpus luteum to continue functioning & to produce hormones. Hormone Production: continues to produce progesterone, essential for maintaining uterine lining & supporting early pregnancy until placenta takes over hormone production.  Overview of Menstrual cycle Divided into phases based on changes in ovaries & endometrium Ovari ovaries es Follicular phase: menstruation follicular phase= crucial for Follicular ovulation day I until ovulation development of oocyte & phase Luteal phase preparation of uterine lining for Ovulation possible pregnancy. Luteal phase: ovulation until day I of menstruation Withdrawal of ovarian hormones (progesterone & oestrogen) causes endometriu menstruation and new cycle begins (breakdown of uterine lining= resulting in menstruation) New follicles begin to grow Endometr m ium Menstrual Proliferativ e Secretion (early &  Ovarian cycle of Follicular phase menstruation From menstruation day until Ovulation phase FSH stimulates Graafian Luteal phase From ovulation (15-28) until ovulation (1-14) follicle to enlarge day 1 of menstruation Average for menstruation 4 – 5 Rapid oestrogen increase Following ovulation empty days Ovaries contain only triggers LH secretion on follicle stimulated by LH primordial & primary follicles day 13 It forms corpus luteum Granulosa cells secrete LH surge triggers follicle Progesterone levels rise oestrogen Oestrogen levels rupture on day 14 rapidly following ovulation – highest 2 days before ovulation Ovulation occurs and peak in luteal phase Some follicles grow and become secondary oocyte is Peak is approx 1 week after secondary follicles released ovulation One follicle from one ovary becomes Graafian follicle  Fallopian tube Oestrogen and (Oviduct) progesterone influences Movement of cilia Smooth muscle contractions Secretion of mucus from peg cells Function of oviduct Propels egg from ovary to uterus  Fallopian tube (Oviduct) Uterine / interstitial part (medial end) Opening into uterine wall Simple columnar epithelium with cilia & without cilia Highly muscular (inner circular & outer longitudinal) Isthmust Narrowest part Simple columnar epithelium with cilia & without cilia Highly muscular (inner circular & outer longitudinal) Ampulla Widest part Site of fertilisation Simple columnar epithelium with cilia & without cilia Less muscular (inner circular & outer longitudinal) Infundibulum (lateral end) Funnel-shaped end Has fimbriae (fingerlike processes) to catch egg Highly convoluted simple columnar epithelium with cilia & without cilia Lowest layer of muscle (inner circular & outer longitudinal)  Fallopian tube  Mucosa (Oviduct) Folded (mostly in ampulla & infundibulum) Lined by 2 cell types: simple columnar epithelium with cilia (F: propels egg to uterus) simple columnar epithelium (Peg cells) – not ciliated (F: secrete nutrient-rich fluid to support egg in travels) Lamina propria (thin layer)  Muscularis (M) 2 layers = inner circular (very thick in isthmus) & outer longitudinal  Serosa (S) With bloodvessels, nerves Continuous with broad ligament BL. Serosal layer & BL have mesothelium = serosa  Fallopian tube (Oviduct)-  Mucosa Ampulla Lined by 2 cell types (E): simple columnar epithelium with cilia (F: propels egg to uterus) simple columnar epithelium (Peg cells) – not ciliated (F: secrete nutrient-rich fluid to support egg in travels) Lamina propria (thin layer) ST Epithelial cells with cilia Peg cells without cilia  Uter us Continuous with uterine tube lumen Pear-shaped muscular organ between bladder & rectum Grows cyclically as a result of oestrogen and progesterone stimulation Shed during menstruation  Uter us functional layer Endometrium functional layer (mucosa) basal layer Epithelium & areolar connective tissue basal layer Myometrium (muscularis) Smooth muscle layer Perimetrium (serosa) Epithelium &  Uterus: Endometrium Mucosa  Covered with simple columnar epithelium some ciliated (F: help move mucus/ fluids/ ova) some have microvilli  Stromal cells (atypical connective tissue) spindle-shaped with plump spindle-shaped nuclei and scanty cytoplasm.  Uterus: Endometrium Structure of the Uterus - YouTube Uterus wall: Uterus: Myometrium main bulk of the uterus consists of smooth muscle composed of interlacing bundles of long slender fibres arranged in ill-defined layers contains bundles of smooth muscle fibres in: transverse (T) longitudinal (L) oblique sections (O) Uteral (endometrium) cycle of menstruation Menstrual Proliferation Early Late phase phase Secretory Secretory  Menstrual Phase: Onset of menstruation In (Day 1-4) absence of implantation:  termination of oestrogen & progesterone secretion  constriction in spiral arterioles of functional layer Cause ischaemia  degeneration of superficial layers of endometrium  & leakage of blood into stroma Stromal cells disaggregate & endometrial glands collapse  Proliferative Phase (Day 5-14) Early proliferative phase Functional layer (stratum functionalis) becomes enlarged Basal layer (stratum basalis) no change Tubular glands become coiled & more closely packed Late proliferative stage: endometrium doubles in thickness  Secretory Phase (Day 15-28) After ovulation: secretory phase - has glands Cytoplasmic vacuoles = on luminal aspect of cell & nucleus at base vacuoles have glycogen & glycoproteins - apocrine-type secretion. Stroma becomes highly vascular & interstitial fluid accumulates between stromal cells  Early vs late Secretory Early Phase Late secretory secretory functional layer basal layer  Cervix Uterus narrows to form a (neck) cervix (endocervix- start at internal os) (ectocervix – start at external os) Cervix opens into the vagina Physical barrier between vagina & uterus is a plug of cervical mucous Structure of the Uterus - YouTube  Cervix (low magnification) Endocervical canal (EC) = lined by simple tall columnar epithelium (mucus-secreting) Junction (J) between ecto- & endocervical epithelium At area/junction where cervix is exposed to vagina (V) = ectocervix - lined by stratified bulk of cervix have squamous Function epithelium` of cervix collagenous tissue with a little Produce mucus (for sperm & smooth muscle.  Vagina (low 1. magnification) 1. Mucosa a) lined by unkeratinised a. stratified squamous epithelium b) fibrous lamina propria have b. many elastic fibres & rich plexus of small 2. Muscularis layer veins & no 2. glands muscle = smooth bundles c) ill-defined inner c. circular d. d) & outer longitudinal 3. Adventitia layers Adventitial layer merges with adventitial layers of bladder anteriorly 3. & rectum posteriorly Function of vagina Canal that connects cervix to  Vagina (high magnification) Epithelial layer = Vacuolized = contain glycogen granules During menstrual cycle, this undergoes cyclical changes in glycogen levels The superficial cells produce glycogen that is anaerobically metabolized by vaginal commensal bacteria to form lactic acid  Summary ovary Fallopian tube Uteru Proliferati s ve Early Late Cerv Vagina secretory sceretory ix