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