Histology Female Reproductive Tract 2024 PDF

Histology of the female reproductive system Author: Dr. Diana A. Vera Estrada Modified: Dr. Flores and Dr. Guzmán Learning Objectives Understand the process of oogenesis Identify the histological features of: Vulva Vagina Ectocervix Transformation zone Endocervix Uterus Fallopian Tube Ovary Ovaries...

Histology of the female reproductive system Author: Dr. Diana A. Vera Estrada Modified: Dr. Flores and Dr. Guzmán Learning Objectives Understand the process of oogenesis Identify the histological features of: Vulva Vagina Ectocervix Transformation zone Endocervix Uterus Fallopian Tube Ovary Ovaries :FUNCTIONS Oogenesis (production of gametes) 1. Oogenesis Oocytes (developing gametes) Ova (mature gametes) 2. Steroidogenesis: Estrogens Progestogens Oogenesis The process of development of female gametes (also called ova or eggs), that takes place in ovaries. The process of oogenesis begins before birth and then development is suspended until puberty. Development resumes with ovulation and the final step (meiosis II) is completed only if fertilization occurs. Folliculogenesis The process by which the female germ cell develops within the somatic cells of the ovary and matures into a fertilizable egg FETAL PERIOD AFTER BIRTH 4th week of gestation: Replication of oogonia begins 4 weeks after All oogonia have formed into primary oocytes Meiosis starts Resulting cell: Oogonium Resulting cell: Primary oocyte The primary oocyte , is arrested in prophase of meiosis I , due to the release of the factor known as oocyte maturation inhibitor by the follicular cells surrounding it Light micrograph of the ovarian cortex (×270) Primordial follicles, ovary, monkey, H&E ×450. squamous follicular cells (F). The nucleus (N) of the oocyte is typically large, oocyte (X). Multilaminar Primary Follicle Several layers of cells around the primary oocyte. Follicular cells are referred to as granulosa cells. ZONA PELLUCIDA The proliferative activity of the granulosa cells is due to the growth factors activin , bone morphogenic protein-15 , and growth differentiation factor-9 produced by the primary oocyte. Histologically: Stains deeply with acidophilic stains and with the periodic acid–Schiff (PAS) reagents. Secondary Follicle Theca externa, composed mostly of fibrous connective tissue. Theca interna a richly vascularized cellular layer. Antrum blood plasma and secretory product Growth of primary oocyte Graafian follicle 100×. H&E. Mature Follicle Corpus luteum Granulosa-lutein cells Theca-lutein cells. Basement membrane disintegrates. Corpus luteum is LH dependent. The fibrous connective tissue that forms in the place of the corpus luteum is known as the corpus albicans Ovarian Structure Composed of: Cortex Medulla Ovarian Cortex: The interstitial compartment housing fibroblast-like stromal cells (also known as interstitial cells). Ovarian follicles in various stages of development. Germinal epithelium The surface of the ovary : simple cuboidal epithelium. The germinal epithelium, is continuous with the mesothelium that covers the ovary (mesovarium). Tumors that arise from the epithelial surface of the ovary account for more than 70% of ovarian cancers. The medulla Composed of fibroblasts loosely embedded in a collagen-rich meshwork containing elastic fibers. Contains also large blood vessels, lymph vessels, and nerve fibers. Hilar cells : contain the same substances in their cytoplasm as Leydig cells of the testes. These cells secrete androgens. Tunica albuginea: A dense irregular connective tissue layer, lies between the germinal epithelium and the underlying cortex. Germinal epithelium (GEp). Tunica albuginea (TA); Primordial follicles (PF ). Growing follicles (SF ), Atretic follicle (AF ), Theca interna (TI), Granulosa cells (GC), Antrum (A). Oviducts (Fallopian Tubes) Four anatomical regions: Infundibulum (with projections called fimbriae). Ampulla Isthmus Intramural region Mucosa (Oviducts) Characterized by many longitudinal folds. Simple columnar epithelium lines the lumen Nonciliated peg cells Ciliated cells Uterus Fundus, body, and cervix. Uterine wall of the body and the fundus is composed of: Endometrium Myometrium Adventitia or a serosa Endometrium Simple columnar epithelium and a lamina propria. Epithelium: Non ciliated secretory columnar cells Ciliated cells. Lamina propria: Branched tubular glands that extend as far as the myometrium. Dense, irregular collagenous connective tissue. Star-shaped cells, macrophages, leukocytes, and an abundance of reticular fibers. Two layers Functionalis thickness ranges between 1 and 7 mm. (Sloughed at menstruation) Basalis. approximately 1 mm in thickness. Regenerates the functionalis layer Myometrium Inner longitudinal Middle circular Outer longitudinal layers SMOOTH MUSCLE Stratum vasculare. (middle layer) ARCUATE ARTERIES As the uterus narrows toward the cervix, the smooth muscle tissue diminishes and is replaced by fibrous connective tissue. At the cervix: dense, irregular collagenous connective tissue. Uterine Serosa and Adventitia Anterior portion is covered by adventitia (connective tissue without an epithelial covering). Fundus and posterior portion of the body are covered by a serosa (layer of squamous mesothelial cells resting on loose connective tissue) Cervix Terminal end of the uterus → extends into the vagina. Lumen: lined by a mucus-secreting simple columnar epithelium (endocervix) External surface: stratified squamous nonkeratinized epithelium (ectocervix) similar to that of the vagina. TRANSITION ZONE Squamocolumnar junction (most common area for cervical cancer; sampled in Pap test) transformation zone squamocolumnar junction Vagina Fibromuscular sheath extending from the cervix to the vestibule (area between the labia minora) Three layers: ✓ Mucosa ✓ Muscularis: Smooth muscle cells ✓ Adventitia: fibroelastic connective tissue Lumen: Thick stratified squamous nonkeratinized epithelium. Epithelial cells are stimulated by estrogen to synthesize and store large deposits of glycogen → released into the lumen. Natural vaginal bacterial flora metabolize the glycogen → lactic acid: responsible for the low pH in the lumen of the vagina External Genitalia stratified squamous epithelium Labia majora, labia minora, vestibule, and clitoris. Labia majora: two folds of skin heavily endowed with adipose tissue and a thin layer of smooth muscle. Labia minora: two smaller folds of skin devoid of hair follicles and adipose tissue. Their core is composed of a spongy connective tissue containing elastic fibers arranged in networks. They contain numerous sebaceous glands and are richly supplied with blood vessels and nerve endings. The vestibule Lesser vestibular glands (also called Skene’s glands), Bartholin’s glands (1cm) They secrete lubricating mucus. Bibliography: Mescher, A. L., Mescher, A. L., & Junqueira, L. C. U. (2018). Junqueira's basic histology: Text and atlas (Fifteenth edition.). New York: McGraw-Hill Education. Gartner, Leslie P. PhD. Female Reproductive System. Textbook of histology. 2017. 4TH Edition. Elsevier. Michael H. Ross. Female Reproductive System. Histology and text Atlas with correlated cell and molecular biology. 6th edition. Lippincott Williams and Wilkins. Images Victor P. Eroschenko. Female Reproductive System. Di Fiore’s Atlas of histology with functional correlations. 11th edition. Abraham L. Kierszenbaum. Histology and cell biology 3rd edition. Elsevier.