Female Reproductive Anatomy & Histology PDF

Female Reproductive Anatomy & Histology Gabin: [email protected]  Vulva The vulva (pudendum) refers to the external female genitalia. Functions include sensation during sexual intercourse, directing flow of urine in micturition, protection of internal reproductive tract from infection S...

Female Reproductive Anatomy & Histology Gabin: [email protected]  Vulva The vulva (pudendum) refers to the external female genitalia. Functions include sensation during sexual intercourse, directing flow of urine in micturition, protection of internal reproductive tract from infection Structures Mons pubis = subcutaneous fat pad anterior to the pubic symphysis. Fusion of the labia majora Labia majora = two hair-bearing external skin folds ○ Extends posteriorly to the posterior commissure (depression over perineal body) ○ Derived from labioscrotal swellings Labia minora = two hairless folds of skin, which lie within the labia majora ○ Fuse anteriorly to form the hood of the clitoris ○ Extend posteriorly either side of the vaginal opening ○ Merge posteriorly into a a fold of skin known as the fourchette Vestibule = area enclosed by labia minora (contains openings of vagina and urethra) Bartholin’s glands = secrete lubricating mucus during sexual arousal. Located either side of vaginal orifice Clitoris = located under clitoral hood. ○ Formed from erectile corpora cavernosa tissue - engorged during arousal ○ Embryologically derived from genital tubercle Vulva Neurovasculature Arterial supply = internal and external pudendal arteries Venous drainage = pudendal veins (+ tributary labial veins) Lymphatic drainage = superficial inguinal nodes Innervation ○ Sensation Anterior = ilioinguinal nerve + genitofemoral nerve (genital branch) Posterior = pudendal nerve (perineal branch) + posterior cutaneous nerve of the thigh ○ PNS Clitoris and vestibule = cavernous nerves (from uterovaginal plexus  Vagina Distensible muscular tube which extends posterosuperiorly from the external vaginal orifice to the cervix Anatomical relations Anterior - bladder and urethra Posterior = rectouterine pouch, rectum and anal canal Lateral = ureters and levator ani muscle Structures Vagina appears as a H shape in the sagittal plane Posterior fornix (horn/ dome) = natural reservoir for semen after ejaculation Anterior fornix Histology (4 layers) Stratified squamous epithelium Elastic lamina propria Fibromuscular layer of smooth muscle ○ Inner circular ○ Outer longitudinal Adventitia = fibrous outer layer Vagina Neurovasculature Arterial supply = uterine artery + vaginal artery (branches of internal iliac artery) Venous drainage = vaginal venous plexus → uterine veins → internal iliac vein Lymphatic drainage ○ Superior = external iliac nodes ○ Middle = internal iliac nodes ○ Inferior = superficial inguinal nodes Innervation ○ Autonomic (SNS and PNS) = uterovaginal plexus (subsidiary of inferior hypogastric plexus) ○ Inferior ⅕ receives somatic innervation = deep perineal nerve (branch of pudendal nerve) Cervix Lower portion of the uterus, connecting the vagina to the main body of the uterus. Anatomically and histologically distinct from the uterus Structure Ectocervix = portion of cervix which projects into vagina ○ Non-keratinized stratified squamous epithelium ○ Separated from endocervical canal by external os (orifice) Endocervical canal/ endocervix = proximal part of cervix ○ Mucus-secreting simple columnar epithelium ○ Separated from uterus by internal os Neurovasculature Arterial supply = uterine artery Venous drainage = uterine vein Lymphatic drainage = iliac, sacral, aortic and inguinal lymph nodes Innervation = uterovaginal plexus Uterus Thick-walled muscular organ connected distally to the vagina and laterally to the uterine tubes. Divided into 3 parts: Fundus = top of uterus, above entry point of fallopian tubes Body = site of implantation of blastocyst Cervix = lower part of uterus linking to the vagina Anatomical position = posterior superior to bladder and anterior to rectum Anteverted = rotated forward with respect to the vagina Anteflexed = flexed anteriorly with respect to the cervix Uterus Neurovasculature (same as cervix) Arterial supply = uterine artery Venous drainage = uterine vein Lymphatic drainage = iliac, sacral, aortic and inguinal lymph nodes Innervation = ovarian and uterine plexus (from inferior hypogastric plexus) Uterus The uterus can be divided into 3 layers: Outer serosa/ adventitia ○ Depending on area of uterus, it can either be: Serosa = connective tissue and visceral peritoneum Adventitia = connective tissue only Myometrium = thick layer of smooth muscle ○ Normally about 2cm thick ○ Grows significantly during pregnancy due to hypertrophy and hyperplasia Endometrium = inner mucosal layer Endometrium Consists of an epithelium and lamina propria ○ Epithelium = simple columnar epithelium with ciliated and secretory cells ○ Lamina propria = contains simple tubular glands in connective tissue The endometrium can be subdivided into: Functionalis Basalis Part which is sloughed off Part which is retained after menstruation which subsequently during menstruation and proliferates and provides a new epithelium and lamina propria replaced during each for renewal of the endometrium menstrual cycle. Can be Bases of glands which lie deep within the basalis are the source further divided into 2 layers of the cells which regenerate the endometrium ○ Zona compacta ○ Have different morphology depending on stage of the (superficial) menstrual cycle ○ Spongiosum layer ○ Between them, there is connective tissue stroma which (deep) contains mesenchymal-type cells and extracellular matrix Endometrium Follicular/ proliferative phase ○ Estrogen causes mitotic activity in the glands and stroma ○ Increase in endometrial thickness from 2 to 9 mm Luteal/ secretory phase ○ Progesterone causes restriction of mitotic activity ○ This causes endometrial glands to produce and secrete glycogen rich vacuoles causing: Stromal oedema Stromal cell enlargement Spiral arterioles development - lengthening and coiling Fallopian Tubes Fertilisation occurs in the ampullary region of the fallopian tube ○ Implantation occurs in the uterus but may implant ectopically The entrance of the fallopian tube is surrounded by fimbriae ○ An ovary is not directly connected with the fallopian tube ○ When ovulation occurs, hormone activate the fimbriae causing it to swell with blood and sweep an oocyte into the fallopian tube Cilia sweep the ovum into the fallopian tube ○ 50% of cells in the fimbria have cilia The fallopian tube can be divided into 4 segments ○ Fibria ○ Infundibulum = funnel shaped opening near ovary ○ Ampulla = widest section of tube ○ Isthmus = narrowest section connecting to uterine cavity Neurovasculature = same as cervix and uterus Fallopian Tubes Wall of the fallopian tube = 3 layers Mucosa = simple columnar epithelium with ciliated cells and secretory cells ○ Cilia propel the oocyte towards the uterus ○ Secretory cells produce a secretion which promotes capacitation of spermatozoa and nutrient functions for the ovum Lamina propria = loose connective tissue Muscularis = inner circular and outer longitudinal layers of smooth muscle Ovary Female gonads which develop from within the abdomen and descend through the inguinal canal Paired organs attached to the posterior surface of the broad ligament by the mesovarium Structure Surface = simple cuboidal epithelium Outer cortex = connective tissue stroma and ovarian follicles Inner medulla = Lots of connective tissue and rich neurovascular supply Ovary Neurovasculature Arterial supply = ovarian arteries (from abdominal aorta) Venous drainage = ovarian veins ○ Left ovarian vein → left renal vein ○ Right ovarian vein → IVC Lymphatic drainage = para-aortic lymph nodes Innervation ○ ANS = ovarian and uterine plexus (from inferior hypogastric plexus) Ovary Almond shaped Simple/ cuboidal outer epithelium with an underlying tunica albuginea Can be subdivided into the: ○ Cortex (outer) Mostly consists of ovarian follicles at various stages in development Follicle = oocyte surrounded by 1 or more layers of granulosa cells Approximately 200,000/ ovary in a normal woman ○ Approximately 20 follicles enter growth phase each cycle Remainder of cortex = connective tissue stroma with fibroblasts ○ Medulla (inner) Loose connective tissue stroma with a rich vascular bed Large follicles may extend into the medulla The ovaries are covered by visceral peritoneum Follicles Primordial Follicles Primary oocyte surrounded by a simple squamous epithelium of stromal cells/ pre-granulosa cells 30 µm in diameter Found at the periphery of the cortex Primary Follicles Grows to about 75 µm in diameter Epithelium becomes simple cuboidal epithelium Pre-granulosa cells → granulosa cells Secondary Follicles Zona pellucida forms between the follicles and granulosa cells Granulosa becomes a stratified cuboidal epithelium Early Antral Follicles Exhibits the beginnings of the antrum formation (space filled with fluid) Begins to synthesise and secrete estrogen Implanted in the uterine lining ○ Surrounding the oocyte is the cumulus oophorus ○ Surrounding the follicular cells are the thecal cells which produce estrogen Follicles Antral Follicle Complete formation of the antrum Graffian/ mature/ Development of a dominant follicle tertiar/ pre-ovulatory Corona radiata present follicle Restriction of blood flow to the oocyte can cause it the follicle to rupture and be ovulated from the ovary Corpus Luteum and After ovulation, the ruptured follicle is retained in the ovary as the corpus luteum Corpus Albicans ○ Secretes predominantly progesterone and estrogen Develops a rich blood supply If there is no pregnancy, the corpus luteum degenerates into the corpus albicans (fibrous tissue that is gradually reabsorbed in the ovary leaving a visible white scar-like tissue)