4.01 Histology of Uterus and Ovary
Mucosa of endometrium
*Simple columnar epithelium* with apical cilia Lamina propria with type III collagen fibers, fibroblasts, ground substance - *uterine glands* - simple tubular or simple coiled tubular
Surface epithelium of ovaries
*Simple cuboidal* Modified mesothelial cells Line peritoneal cavity
Corpus luteum
Large *temporary endocrine gland* that forms after ovulation Granulosa and thecal layers collapse and fold - invaded by capillaries Blood clot forms within remnant of antrum - replaced by scar tissue Cells change structurally and functionally after exposure to LH - secrete *estrogen, progesterone, androstenedione, inhibin*
Serosa of uterine tubes
Loose CT - covered by mesothelium *letter A in picture
Medulla of ovaries
Loose CT - vessels enter thru hilum
Perimetrium
Serosa of loose CT covered with mesothelium Continuous with ligaments
Theca lutein cells
Small cells in corpus luteum - oval nuclei - darker staining - lipid droplets - cluster in folds *yellow arrow in picture
Menstrual phase
Spiral arteries: - vasoconstriction produces ischemia and rupture of capillaries - limited blood loss Uterine glands: - necrosis Surface epithelium, blood, uterine secretions, and tissue debris are sloughed off
Follicular theca
Stromal cells immediately outside follicle Most prominent around mature follicles 2 layers: interna and externa
Proliferative phase (controlled by estrogen from follicle)
Which phase of uterine cycle? Cells in basal ends of glands proliferate, migrate, and form new epithelium. Uterine glands: - lengthen and *straighten* - nearly empty lumens Vessels: - spiral arteries lengthen
Secretory phase (controlled by progesterone from corpus luteum)
Which phase of uterine cycle? Glandular cells secrete and accumulate glycogen - dilate glandular lumens - glands become *coiled* Stroma: - cells enlarged and pale staining Vessels: - spiral arteries extend to surface - lacunae present Maximum thickness via accumulation of secretions and edema in stroma
Muscularis of uterine tubes
2 layers of smooth m. - inner circular - outer longitudinal *letter B in picture
Granulosa lutein cells
80% of corpus luteum Polyhedral cells - round nuclei - lipid droplets - lipofuscin (gives corpus luteum yellow color) *red arrow in picture
*Functional layer* of mucosa of endometrium
Distinct layer of mucosa of endometrium *Simple columnar* Spongy lamina propria with uterine glands Supplied by *spiral arteries* - branch into capillaries - lead to vascular lacunae - drained by efferent veinules *Significant changes during menstrual cycles*
Mucosa of uterine tubes
Branching longitudinal folds - prominent in ampulla - decrease in height and complexity closer to uterus - absent in intramural part *Simple columnar epithelium* - 2 cell types: ciliated cells and peg cells Lamina propria of loose CT *letter C in picture
Secondary / Antral follicle
Deeper in ovarian cortex Primary oocyte with zona pellucida Granulosa: - stratified cuboidal - secrete follicular fluid - *cumulus oophorus* - small cluster of granulosa cells that protrudes into antrum Antrum: - irregular fluid-filled space between granulosa layers - follicular fluid - *progesterone and estrogens*
Follicular atresia
Degeneration of follicle Oocyte undergoes autolysis Granulosa undergoes apoptosis and detachment Zona pellucida collapses Theca cells become vascularized cords replaced by CT Glassy membrane forms from basement membrane thickening Most prominent just after birth, during puberty, and pregnancy
Tunica albuginea of ovaries
Dense irregular CT capsule - deep to surface epithelium
*Basal layer* of mucosa of endometrium
Distinct layer of mucosa of endometrium *Adjacent to myometrium* Highly cellular lamina propria with basal ends of uterine glands Supplied by *straight arteries* *Relatively unchanged* during menstrual cycle
Theca externa
Fibrous layer (fibroblasts and smooth m) Merges with surrounding stroma *letter D in picture
Primordial follicle
Formed during fetal life In superficial ovarian cortex Primary oocyte: - spherical with large nucleus Follicular cells: - simple squamous epithelium Basal lamina: - clear boundary between follicle and stroma
Mature / Graafian follicle
Forms bulge at ovary surface visible via ultrasound Primary or secondary oocyte with zona pellucida Granulosa: - layers appear thinner - cumulus oophorus - corona radiata - surrounds zona pellucida Antrum is one large space Follicular theca - thick layers
Cortex of ovaries
Highly cellular CT where ovarian follicles reside
Peg cells
Part of mucosa of uterine tubes Nonciliated, darker staining *Apical bulge into lumen* Secrete *glycoprotein rich mucus* - nutritive and protective functions for oocyte and sperm - *capacitation factors activate sperm* *# 2 in picture
Ciliated cells
Part of mucosa of uterine tubes Spherical nuclei Apical cilia sweep oocyte and fluid toward uterus
Corpus luteum of menstruation
Persists for part of only 1 menstrual cycle Remnants from regression are phagoytosed by macrophages Fibroblasts invade area and produce corpus albicans
Multilaminar primary follicle
Primary oocyte - microvilli extend into zona pellucida Zona pellucida: *produced by the oocyte* - glycoprotein ECM layer between oocyte and granulosa cells - required for sperm binding and fertilization Granulosa: - stratified cuboidal - microvilli extend into zona pellucida
Primary follicle
Primary oocyte: - larger with more mitochondria, ER, and larger golgi - *cortical granules with proteases* Follicular / granulosa cells: - simple or stratified cuboidal - cytoplasm appears granular 2 types: - unilaminar - multilaminar
Corpus albicans
Remnant of corpus luteum Dense irregular CT scar (collagen + fibroblasts)
Myometrium
Thickest layer of uterus 3 layers of smooth m: - inner longitudinal - middle circular - outer longitudinal Also in the layer: - CT - venous plexuses and lymphatics
Corpus luteum of pregnancy
Very large and occupies most of ovary Secretes progesterone Maintained by HCG for several months Degenerates and replaced by large corpus albicans
Theca interna
Well-vascularized endocrine tissue - steroid-producing (*secrete androstenedione*) Round cells: - round nucleus - lipid droplets - lightly stained