Histology of the Female Reproductive Tract PDF

Histology of the female reproductive tract Joyce El-Haddad [email protected] @orientatewithjoyce Lecture Outline • Overview of the female reproduc3ve tract • Ovary • Uterine Tube • Uterus • Cervix • Vagina • Mammary Glands • Clitoris Overview of the female reproductive tract Ovary • 2 o...

Histology of the female reproductive tract Joyce El-Haddad [email protected] @orientatewithjoyce Lecture Outline • Overview of the female reproduc3ve tract • Ovary • Uterine Tube • Uterus • Cervix • Vagina • Mammary Glands • Clitoris Overview of the female reproductive tract Ovary • 2 ovaries • Almond shaped glands located on the lateral walls of the lesser pelvis • Histologically, consists of a cortex and medulla. • Function: ØProduction of gametes ØProduction of hormones (oestrogen, progesterone, relaxin) Histology of the ovary • Ovarian surface is covered by germinal epithelium/ovarian surface epithelium • The ovary is poorly divided into an outer cortex and an inner medulla • Under the surface epithelium = DICT aka the tunica albuginea CORTEX AND MEDULLA OF OVARY • The cortex is normally filled with numerous ovarian follicles in various stages of development. • Medulla = highly vascularized region • Demarcation between cortex and medulla = ambiguous. Ovarian Cortex The ovarian cortex contains: 1. 2. 3. 4. Stroma Ovarian follicles Corpus luteum Corpus albicans Menstrual Cycle Primordial follicles Light micrograph (LM) of the surface of the ovary. The ovarian surface epithelium (OSE) consists of one layer of cuboidal to columnar cells. A basement membrane separates them from underlying tunica albuginea (TA). 390×. H&E. Primordial follicles FC LM of part of the ovarian cortex. Markedly cellular connective tissue stroma surrounds primordial (PF), primary (1F), and secondary (2F) ovarian follicles. 295×. H&E. FC O O Stroma LM of a primordial follicle in the ovarian cortex. One layer of squamous follicular cells (FC) surrounds a primary oocyte (O). The oocyte has a large vesicular nucleus. The clear space between oocyte and follicular cells is a cell shrinkage-related preparation artifact. 790×. H&E. LM of a primary follicle. One layer of cuboidal follicular cells (FC) envelops an oocyte (O). Surrounding stroma is highly cellular and contains elongated cells, some of which will become theca interna cells. The space between oocyte and follicular cells is a preparation artifact. 790×. H&E. Primordial Follicles • Primordial follicles are formed during fetal life • They have 3 major components: 1- A primary oocyte with a large nucleus and prominent nucleolus 2- Follicular cells: A single layer of the flattened cells (squamous cells) enveloping the primary oocyte 3- Basal lamina: • Surrounds the follicular cells • Marking a clear boundary between the follicle and the vascularized stroma and acts as a blood-follicle barrier • These follicles are located just underneath the tunica albuginea • After puberty, 20 primordial follicles become activated during the menstrual cycle each month (Gonadotropin Releasing Hormone DEPENDENT) • On average, one follicle from here becomes dominant and goes on to become a primary follicle • BEFORE puberty, some primordial follicles can develop into primary under the influence of GH. This is Gonadotropin Independent Recruitment. Primary Follicles PF Primary follicles TA (X200; PT; Primary follicles) • PF: primordial follicles • UF: unilaminar primary follicles • F: follicle cells • Arrows: epithelial follicular cells 2F Stroma (X200; PSH; A multilayered primary follicles) (activeof follicular cells) cortex. Markedly cellular connective tissue LMcells of part the ovarian Light micrograph (LM) of the surface of the ovary. The ovarian• G: granulosa • O: oocyte stroma surrounds primordial (PF), primary (1F), and secondary (2F) ovarian surface epithelium (OSE) consists of one layer of cuboidal to columnar cells. • ZP: zona pellucida follicles.membrane 295×. H&E. A basement membrane separates them from underlying tunica albuginea • BS: basement (TA). 390×. H&E. FC FC O O Stroma LM of a primordial follicle in the ovarian cortex. One layer of squamous follicular cells (FC) surrounds a primary oocyte (O). The oocyte has a large vesicular nucleus. The clear space between oocyte and follicular cells is a cell shrinkage-related preparation artifact. 790×. H&E. LM of a primary follicle. One layer of cuboidal follicular cells (FC) envelops an oocyte (O). Surrounding stroma is highly cellular and contains elongated cells, some of which will become theca interna cells. The space between oocyte and follicular cells is a preparation artifact. 790×. H&E. Histology of primary follicles • Stromal (supporting) cells immediately outside each growing primary follicle • Differentiate to form the two distinct vascularized tissue around the follicle: 1. 2. Theca interna § A well-vascularized endocrine tissue § With typical steroid-producing cells secreting androstenedione § Nuclei = round Theca externa § A fibrous tissue with fibroblasts, macrophages, and smooth muscle merges gradually with the surrounding stroma § Nuclei = flat Zona pellucida: • A layer between oocytes and follicular cells • Containing 4 glycoproteins (ZP1, ZP2, ZP3, ZP4) secreted by the oocyte. (X200; PSH; A multilayered primary follicles [monkey]) • GC: granulosa cells • ZP: zona pellucida Primary follicles • Slightly larger than primordial follicles • The oocyte is now surrounded by cuboidal cells which have a busy cytoplasm – a granular appearance. • The cuboidal granular cells = granulosa cells. • The stromal tissue around the follicle differentiates into a concentric sheath of theca interna cells. (TI) • TI have receptors for luteinizing hormone How to spot a primary follicle: Growth of a small group of primordial follicles each month (beginning in puberty): 1. Growth of the oocyte 2. ProliferaJon and changes in the follicular cells There are two types of primary follicles: • Unilaminar primary follicle: § A simple cuboidal epithelium (follicular cells) around the growing oocyte • MulJlaminar primary follicle: § A straJfied follicular epithelium (granulosa) § Follicular cells: now termed granulosa cells (sJll avascular and surrounded by a basement membrane) Secondary Follicle Secondary (Antral) Follicles • As the primary follicles grow, they move deeper into the ovary cortex • From here we get the secondary follicles • They are demarcated by the presence of an antrum (cavity) (X100; H&E; Antral follicle) • A: antrum • O: oocyte • ZP: zona pellucida • G: granulosa cells • TI: theca interna • TE: theca externa (X100; PT; A slightly more developed antral follicle) • A: antrum • O: oocyte • CR: corona radiata • CO: cumulus oophorus • G: granulosa layer • TI: theca interna • TE: theca externa Histological features of the secondary follicle 1- Primary Ooctye 2- Granulosa cells - 3 locations – 3 descriptions: A. Stratum granulosum: Line the follicular wall B. Cumulus oophorus: The hillock of granulosa cells around the oocyte C. Corona radiata: The tightly adhering granulosa cells immediately surrounding the zona pellucida Leave with the oocyte at ovulation 3- Antrum – fluid filled cavity 4- Follicular theca: A. Theca interna – receptors of LH B. Theca externa (X100; H&E; Antral follicle) • A: antrum • O: oocyte • ZP: zona pellucida • G: granulosa cells • TI: theca interna • TE: theca externa (X100; PT; A slightly more developed antral follicle) • A: antrum • O: oocyte • CR: corona radiata • CO: cumulus oophorus • G: granulosa layer • TI: theca interna • TE: theca externa (X400; PT; Wall of antral follicle) • A: antrum • G: granulosa cells • BS: basement membrane • TI: theca interna • TE: theca externa • S: stroma Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health (X85; H&E; Secondary/antral follicle) • A: antrum • GC: granulosa cells • TI: theca interna • TE: theca externa Mature Follicle Mature (Graafian) Follicle Features: 1- germ cell/gamete: • Secondary oocytes 2- granulosa cells: A. Membrana granulosa / Stratum granulosum B. Cumulus oophorus C. Corona radiata (ovulate with the oocyte) 3- Antrum: a single large vesicle • Rapidly accumulates more follicular fluid • Expands to a diameter of 2cm • Forms a bulge at the ovary surface visible with ultrasound imaging 4- Follicular theca: A. Theca interna B. Theca externa Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health (X45; H&E; Mature Graaffian follicle) • A: antrum • CO: cumulus oophorus • SG: stratum granulosum • TI: theca interna Ovulation • A hormone-stimulated process by which the oocyte is released from the ovary • Dominant follicle usually reaches the most developed stage of follicular growth and undergoes ovulation, while the other primary and antral follicles undergo atresia • Normally occurs midway through the menstrual cycle (around the 14th day of a typical 28-day cycle) @orientatewithjoyce Corpus Luteum A temporary endocrine gland in the ovarian cortex Formed by: 1- Granulosa cells • Change to granulosa lutein cells • Invaded by capillaries • Increase greatly in size, without dividing, and eventually comprise about 80% of the CL • Secrete large amounts of oestrogen, progesterone, and inhibin 2- Theca interna • Change to theca lutein cells • Half the size of the granulosa lutein cells • Typically aggregated in the folds of the wall of CL • Becomes well vascularized • Produce large amounts of progesterone and androstenedione (X15; H&E; Corpus Luteum) • CL: corpus Luteum • BC: blood clot (X100; H&E; Corpus Luteum) • GL: Granulosa lutein cells • TL: theca lutein cells Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health Female human corpus luteum of menstruation Corpus Luteum in pregnancy If pregnancy occurs: • Uterine mucosa does not undergo menstruation to prevent spontaneous abortion of pre-embryo. • Production of human chorionic gonadotrophin (hCG) by embryo § Maintains and promotes further growth of the corpus luteum At months 4-5 of pregnancy: • Production of progesterone (and estrogens) at levels adequate to maintain the uterine mucosa by placenta • CL degenerates and is replaced by a large corpus albicans Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health (X12; H&E; Human corpus Luteum) • Cav: follicular cavity • Arrows: theca interna (X240; H&E; Human corpus Luteum) • GLC: granulosa lutein cells • TLC: theca lutein cells Corpus Albicans Without further LH s.mula.on and in the absence of pregnancy: • • Reduced steroid produc8on in CL Apoptosis and regression of CL (X60; H&E; Corpus albicans) • CA: corpus albicans Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health (X125; H&E; Corpus albicans of a human ovary) Follicular Atresia Follicular atresia • Degenerative process happens in most ovarian follicles: § Apoptosis § Removal by phagocytic cells Ovarian reserve when menopause begins: >1000 follicles What histological features do you noJce here? (X200; PT; An atretic follicle) • GC: apoptotic granulosa cells • O: degenerative oocyte • A: antrum UTERINE TUBES (Oviducts) Four regions in the following sequence from ovarian end to uterine end: 1- Infundibulum: • Fringed with finger-like extensions called fimbriae proximal to the ovary 2- Ampulla: • The longest and expanded region • Where fertilization normally occurs 3- Isthmus: a more narrow portion proximal to the uterus 4- Uterine / intramural part: • Passes through the wall of the uterus • Opens into the uterine cavity UTERINE TUBES (Oviducts) 1- Mucosa: • Numerous branching, longitudinal folds which are most prominent in the ampulla • Smaller in the regions closer to the uterus and are absent in the intramural portion of the tube Epithelium: simple columnar epithelium § Ciliated cells: ü Ciliary movements sweep fluid toward the uterus § Secretory peg cells: ü Non-ciliated and often darker staining ü Secrete glycoproteins of a nutritive mucus Lamina propria: loose connective tissue 2- Muscularis: Thick, with interwoven circular (or spiral) and longitudinal layers of smooth muscle 3- Serosa: Thin, covered by visceral peritoneum with mesothelium UTERINE TUBES (Oviducts) (X140; H&E; Uterine tube wall) • C: circular layer of smooth muscle • L: longitudinal layer of smooth muscle • LP: lamina propria • Arrows: simple columnar epithelium (X200; PT; Oviduct mucosa) • E: simple columnar epithelium • LP: lamina propria • L: lumen (X400; PT; Oviduct epithelium) • CC: ciliated cells • PC: peg cells UTERINE TUBES (Oviducts) Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health (X16; H&E; Human uterine tube) • BV: blood vessels (X640; H&E; Human uterine tube) • Above the point of the arrow: ciliated cells • Below the point of the arrow: non-ciliated cells UTERUS Three histological layers: 1- Endometrium / Mucosa 2- Myometrium 3- Perimetrium UTERUS HISTOLOGY: Endometrium The Mucosa/endometrium of the uterus consists of: Epithelium: simple columnar epithelium • Ciliated cells • Secretory cells Lamina propria or stroma Zones of endometrium: A. Stratum Functionalis (Functional layer): undergoes profound changes during the menstrual cycles B. Stratum Basale (Basal layer): remains relatively unchanged during the menstrual cycles Two types of arteries in endometrium: 1- Straight arteries: supply only the basal layer 2- Spiral arteries: progesterone-sensitive; bring blood throughout the functional layer Endometrium (X100; Mallory trichrome; Basal layer of endometrium) • B: basal layer • G: uterine glands • A: arteries • M: myometrium (X100; Mallory trichrome; Functional layer of endometrium) • G: uterine glands • A: arteries (X400; Mallory trichrome; Functional layer of endometrium) • SE: surface epithelium • S: stroma UTERUS HISTOLOGY: Myometrium and Perimetrium Myometrium: • A thick tunic of highly vascularized smooth muscle • Interwoven layers, with fibers of the inner and outer layers Perimetrium: • Largely: serosa covered by mesothelium • In some areas: adventitia (X100; Mallory trichrome; Basal layer of endometrium) • B: basal layer • G: uterine glands • A: arteries • M: myometrium Changes in the endometrium Secretory Proliferative Menstrual a (upper panel: X15; lower panel: X55; Proliferative phases) b (upper panel: X20; lower panel: X60; Secretory phases) • Arrows: mucus secretion c (upper panel: X15; lower panel: X55; Menstrual phases) Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health Menstrual ProliferaJve Secretory Changes in the endometrium 1. Proliferative/Follicular/Estrogenic Phase • 8-10 days on average • Increase in the thickness of uterine mucosa (from ~0.5 mm to 2-3 mm thick) • Coincides with the rapid growth of a small group of ovarian follicles growing as vesicular follicles • Estrogens act on the endometrium, inducing regeneration of the functional layer lost during menstruation 2. Secretory/luteal Phase • Starts as a result of the progesterone secreted by the corpus luteum • Maximum thickness (5 mm) of endometrium during the secretory phase as a result of the accumulation of secretions and edema in the stroma 3. Menstrual Phase • Day 1 of the menstrual cycle = the day when menstrual bleeding appears • Lasts 5 days on average • Caused by reduced circulating levels of progesterone and estrogens when fertilization and implantation do not occur/regression of the corpus luteum Cervix (X35 and X400; H&E) o Lower, cylindrical part of the uterus o Extending between internal and external os: • Cervical canal Histologically: 1- Endocervical mucosa 2- Exocervical mucosa (X45; H&E) Cervix (X120; H&E; Exocervix) (X120; H&E; Transformation zone of the cervix) • Arrow: junction between epithelia • CG: mucus-secreting cervical glands (X10; H&E; Human cervix; a postmenopausal woman) • SCE: simple columnar epithelium • SSE: stratified squamous epithelium • X: mucus secreted from the cervical glands Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health VAGINA 1- Mucosa: • Epithelium: § Non keratinised stratified squamous epithelium § When the cells desquamate, bacteria metabolize glycogen to lactic acid, causing a relatively low pH within the vagina • Lamina propria: § No glands; mucus in the vagina is produced by the cervical glands 2- Muscular layer: • Two indistinct layers of smooth muscle: § Circular bundles: next to the mucosa § Longitudinal bundles: near the adventitia 3- Adventitia: • Rich in elastic fibers • Contains an extensive venous plexus, lymphatics, and nerves (X60; H&E; Vagina) • E: epithelium • LP: lamina propria • M: muscular layer (X200; PSH; Vagina mucosa) • LP: lamina propria VAGINA Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health (X40; H&E; Human vagina) External Genitalia / Vulva Include several structures, all covered by stratified squamous epithelium: Vestibule • A space whose wall includes the tubuloacinar vestibular glands Labia minora • Folds of skin lacking hair follicles but with numerous sebaceous glands Labia majora • Homologous and histologically similar to the skin of the scrotum Clitoris • An erectile structure homologous to the penis with paired corpora cavernosa (H&E; Inner surface of the labia minora) • Ep: non-keratinised stratified squamous epithelium • SG: sebaceous glands • SD: sebaceous ducts • Arrows: smooth muscle bundles Source: Michael H. Ross: Histology: a Text and Atlas, 7th Edition Copyright © 2016 Wolters Kluwer Health Mammary Glands Highly modified apocrine sweat glands Each mammary gland: • 15-25 lobes of the compound tubuloalveolar type Each lobe: • Consists of many lobules, sometimes called terminal duct lobular units (TDLU) • A separate gland with its own excretory lactiferous duct Histologic structure: • During Puberty (nonpregnant adults) • During Pregnancy & Lactation • Post-lactational Regression in the Mammary Glands Breasts During Pregnancy & Lactation (X60; H&E; Adult, nonpregnant female) • L: lobule • CT: connective tissue (X60; H&E; during pregnancy) • L: lobule • CT: connective tissue • A: adipocyte (X60; H&E; during lactation) • A: glandular alveoli • D: excretory ducts • Arrows: small septa Actively Developing and Lactating Alveoli (X400; H&E; Glandular alveoli) • A: alveoli • M: myoepithelial cells • D: intralobular ducts • Arrow: milk • L: lymphocytes • V: venules • P: plasma cells (X400; PT; Glandular alveoli) • LD: lipid droplet • V: venule • CT: connective tissue Histology of the Male Reproductive Tract [email protected] @orientatewithjoyce Lecture Outline - Male reproductive system overview - Histology of the testes - Histology of the epididymis and vas deferens - Histology of the seminal vesicle and prostate LEARNING OUTCOMES: LO1: To understand and identify the basic components of male reproductive system LO2: To understand and describe the histological features of testis LO3: To identify cells of the germinal epithelium of the seminiferous tubule: Sertoli cells, spermatogonia, spermatocytes, spermatids and spermatozoa LO4: To understand and identify the structural features of epididymis and vas deferens LO5: To understand and the seminal vesicle, and prostate Overview of male reproductive system Three key functions of this system are production of spermatozoa, delivery of these cells via semen and production of testosterone TESTES Testes – Overview Schematic of tubules and ducts. Vas deferens • • • Ovid gland that sits within the scrotum After spermatozoa are produced in the testes, they travel a long, tortuous route: from seminiferous tubules to the paired rete testis, efferent ductules (ductuli efferenti), epididymis, ductus (vas) deferens. Encased in a thick capsule of dense fibroelastic CT known as tunica albuginea (white) Seminiferous tubules Efferent ductules Rete testis Tubulu recti Lobule Epididymis Epididymis TA Tunica albuginea Testis Vas deferens Light micrograph (LM) of part of the testis at low magnification. A thick capsule—the tunica albuginea (TA)—covers it externally. Parts of the ductus Tunica a LM of a seminiferous tubule in transverse section. A capsule (arrows) surrounds seminiferous epithelium. Spermatogonia (Sg) are at the tubule base; large spermatocytes (Sp) and smaller spermatids (S) are closer to the lumen. Pillar-shaped Sertoli cells (SC) are interspersed with germ cells. A clump of Leydig cells is in adjacent stroma. 450×. H&E. Testes - Seminiferous Tubules - Surrounded by a CT capsule with myoid cells SC Leydig cells Seminiferous tubule Epithelium is stratified epithelium with 2 types of cells: S 1. Spermatogenic cells (germ cells) Sp Sg 2. Sertoli cells 17.4 HISTOLOGY OF SEMINIFEROUS TUBULES A distinct connective tissue capsule, a layer of flattened myoid cells, and a basement membrane surround seminiferous tubules. The seminiferous epithelium is an unusual, complex stratified epithelium with two cell populations: spermatogenic (or germ) cells and nonproliferating Sertoli cells. In a seminiferous tubule, germ cells are at various stages of spermatogenesis. The cells closest to the basement membrane with spherical nuclei are spermatogonia. Larger cells with spherical nuclei but with distinctive Ch017-NB86.indd 381 spaghetti-like chromatin are primary spermatocytes. The haploid secondary spermatocytes are seldom seen; almost as soon as they form they divide and produce spermatids. During a transformation period, spermatids attach to the relatively few Sertoli cells, which are tall and pillar-like. The bases of the Sertoli cells rest on the basement membrane; the free ends of the cells extend radially and reach the lumen. Spermatids, which are known as early and late, do not divide but mature into spermatozoa, which are released into the lumen and carried into efferent ducts. 7/3/2007 11:18 Testes – Spermatogenic cells - The cells closest to the Basement membrane are spermatogonia LM of a seminiferous tubule in transverse section. A capsule (arrows) surrounds seminiferous epithelium. Spermatogonia (Sg) are at the tubule base; large spermatocytes (Sp) and smaller spermatids (S) are closer to the lumen. Pillar-shaped Sertoli cells (SC) are interspersed with germ cells. A clump of Leydig cells is in adjacent stroma. 450×. H&E. SC Leydig cells Seminiferous tubule S - Larger cells with spherical nuclei are primary and secondary spermatocytes Sp Sg - Spermatocytes produce spermatids - Spermatids mature into spermatozoa which are released into the lumen 17.4 HISTOLOGY OF SEMINIFEROUS TUBULES A distinct connective tissue capsule, a layer of flattened myoid cells, and a basement membrane surround seminiferous tubules. The seminiferous epithelium is an unusual, complex stratified epithelium with two cell populations: spermatogenic (or germ) cells and nonproliferating Sertoli cells. In a seminiferous tubule, germ cells are at various stages of spermatogenesis. The cells closest to the basement membrane with spherical nuclei are spermatogonia. Larger cells with spherical nuclei but with distinctive Ch017-NB86.indd 381 spaghetti-like chromatin are primary spermatocytes. The haploid secondary spermatocytes are seldom seen; almost as soon as they form they divide and produce spermatids. During a transformation period, spermatids attach to the relatively few Sertoli cells, which are tall and pillar-like. The bases of the Sertoli cells rest on the basement membrane; the free ends of the cells extend radially and reach the lumen. Spermatids, which are known as early and late, do not divide but mature into spermatozoa, which are released into the lumen and carried into efferent ducts. 7/3/2007 11:18 Testes – Spermatogenic cells • At puberty: primitive germ cells – spermatogonia – enlarge and become mitotically active and undergo spermatogenesis. • This gives rise to spermatozoa. • During differentiation, spermatozoa move towards the lumen. • This process takes about 64-74 days, is coordinated by Sertoli cells and continues throughout life. YOU DO NOT NEED TO KNOW SPERMATOGENESIS IN DETAIL – YOU DO NEED TO KNOW THE CELLS AND WHERE THEY ARE FOUND HISTOLOGICALLY - - - Testes – SERTOLI CELLS Sertoli (sustentacular) cells phagocytose spermatid remnants and secrete fluid and many substances, including androgen- binding protein (ABP), essential for spermatozoa survival. LM of a seminiferous tubule in transverse section. A capsule (arrows) surrounds seminiferous epithelium. Spermatogonia (Sg) are at the tubule base; large spermatocytes (Sp) and smaller spermatids (S) are closer to the lumen. Pillar-shaped Sertoli cells (SC) are interspersed with germ cells. A clump of Leydig cells is in adjacent stroma. 450×. H&E. Leydig cells Seminiferous tubule S This protein binds testosterone and helps maintain a high concentration of testosterone within the testes. Histologically, Sertoli cells are tall and pillar-like. The bases of the Sertoli cells rest on the basement membrane; the free ends of the cells extend radially and reach the lumen. SC Sp Sg 17.4 HISTOLOGY OF SEMINIFEROUS TUBULES A distinct connective tissue capsule, a layer of flattened myoid cells, and a basement membrane surround seminiferous tubules. The seminiferous epithelium is an unusual, complex stratified epithelium with two cell populations: spermatogenic (or germ) cells and nonproliferating Sertoli cells. In a seminiferous tubule, germ cells are at various stages of spermatogenesis. The cells closest to the basement membrane with spherical nuclei are spermatogonia. Larger cells with spherical nuclei but with distinctive Ch017-NB86.indd 381 spaghetti-like chromatin are primary spermatocytes. The haploid secondary spermatocytes are seldom seen; almost as soon as they form they divide and produce spermatids. During a transformation period, spermatids attach to the relatively few Sertoli cells, which are tall and pillar-like. The bases of the Sertoli cells rest on the basement membrane; the free ends of the cells extend radially and reach the lumen. Spermatids, which are known as early and late, do not divide but mature into spermatozoa, which are released into the lumen and carried into efferent ducts. 7/3/2007 11:18 - - - Testes – Intratubular space LM of a seminiferous tubule in transverse section. A capsule (arrows) surrounds seminiferous epithelium. Spermatogonia (Sg) are at the tubule base; large spermatocytes (Sp) and smaller spermatids (S) are closer to the lumen. Pillar-shaped Sertoli cells (SC) are interspersed with germ cells. A clump of Leydig cells is in adjacent stroma. 450×. H&E. Contains CT and Leydig (interstitial) cells Clusters of eosinophilic Leydig (interstitial) cells Leydig cells Seminiferous tubule S Sp Sg 386 Male Reproductive System 17.4 HISTOLOGY OF SEMINIFEROUS TUBULES A distinct connective tissue capsule, a layer of flattened myoid cells, and a basement membrane surround seminiferous tubules. The seminiferous epithelium is an unusual, complex stratified epithelium with two cell populations: spermatogenic (or germ) cells and nonproliferating Sertoli cells. In a seminiferous tubule, germ cells are at various stages of spermatogenesis. The cells closest to the basement membrane with spherical nuclei are spermatogonia. Larger cells with spherical nuclei but with distinctive The Leydig cells have a foamy, washedout cytoplasm is due to high lipid content, as they store cholesterol for synthesis of testosterone. These large polyhedral cells have an eccentric spherical nucleus with one or two prominent nucleoli, and cell surfaces have numerous small microvilli. SC Ch017-NB86.indd 381 spaghetti-like chromatin are primary spermatocytes. The haploid secondary spermatocytes are seldom seen; almost as soon as they form they divide and produce spermatids. During a transformation period, spermatids attach to the relatively few Sertoli cells, which are tall and pillar-like. The bases of the Sertoli cells rest on the basement membrane; the free ends of the cells extend radially and reach the lumen. Spermatids, which are known as early and late, do not divide but mature into spermatozoa, which are released into the lumen and carried into efferent ducts. ST 7/3/2007 11:18:15 AM Cap Leydig cells ST ST LM eosin intima to out 625× EPIDIDYMIS EPIDIDYMIS • Includes head, body, and tail • Responsible for transmitting spermatozoa from the rete testes to the vas deferens EPIDIDYMIS - The epididymal ducts consists of pseudostra*fied epithelium containing basal cells and tall columnar (principal) cells with long, apical, nonmo:le stereocilia projec:ng into the lumen. - Stereocilia amplify the cell surface area and func:on in absorp:on of excess fluid that accompanies spermatozoa from the tes:s. - In transit, spermatozoa mature and acquire mo:lity and fer:lizing capacity. - Loose connec:ve :ssue and some circularly arranged smooth muscle are also found outside the ducts. - The smooth muscle in the head of the epididymis undergoes spontaneous peristal:c contrac:ons. Epididymal duct Male Reproductive System 389 LM of the duct of the epididymis in transverse section. The wall consists of tall pseudostratified epithelium of uniform thickness with apical nonmotile stereocilia. Spermatozoa are in the lumen. Surrounding lamina propria is loose, richly vascular connective tissue. The rectangle indicates an area similar to that seen below. 320×. H&E. High-magnification LM of the epithelium of the epididymis. The two major cell types of the epithelium rest on a basement membrane. Tall columnar cells have elongated, euchromatic nuclei and long, apical stereocilia. Small, round basal cells (arrows) on the basement membrane do not reach the luminal surface. They are most likely germinative stem cells for the epithelium. Underlying fibrous connective tissue contains smooth muscle. 525×. H&E. Stereocilia Lumen DUCTUS (VAS) DEFERENS DUCTUS (VAS) DEFERENS A long straight tube joins with duct of seminal vesicle to form ejaculatory duct which opens in prostatic urethra 390 Male Reproductive System Mucosa DUCTUS (VAS) DEFERENS Lumen Consists of: o Mucosa; Muscularis Adventitia (some § Epithelium: pseudostratified epithelium cells have sparse stereocilia) § Lamina propria: contains many elastic Higher fibres magnification LM o Muscular wall: § Longitudinal inner layer § Middle circular layer § Longitudinal outer layer o Adventitia Muscularis LM of the ductus deferens in transverse section. Folds of mucosa produce a stellate lumen. Around the mucosa is a prominent three-layer coat of tightly spiraled smooth muscle, the muscularis. Blood vessels, nerves, and lymphatics travel through an adventitia of loose connective tissue that covers the ductus externally. 35×. H&E. Adventitia Lumen of the mucosa of the ductus deferens. The highly folded mucosa consists of pseudostratified columnar epithelium, which closely resembles that of the epididymis. Columnar cells with apical stereocilia and a row of small, round basal cells (arrows) are seen. The mucosal folds are due to contraction of underlying smooth muscle. 285×. H&E. Lamina propria Smooth muscle 17.13 HISTOLOGY OF THE DUCTUS (VAS) DEFERENS ductus is more than just a passive conduit for spermatozoa from epididymis to urethra; ultrastructural data suggest that it has both SEMINAL VESICLES Seminal vesicles - Production of semen Seminal fluid is important for semen coagulation, sperm motility, and stability of sperm chromatin and suppression of the immune activity in the female reproductive tract. Male Reproductive System 395 A (20X; H&E; Seminal vesicle) Seminal vesicles • • Arrows: mucosal folds L: lumen B (300X; H&E; Mucosal folds in seminal vesicle) • SM: smooth muscle • LP: lamina propria SM • Mucosa; containing a lot of folds composed of: § Epithelium: simple or pseudostratified columnar epithelial cells rich in LM of the seminal vesicle. The gland’s mucosal folds are complex, and its wall has smooth muscle (SM) secretory granules arranged tightly in inner circular and outer longitudinal Flocculent eosinophilic material fills the lumen. § Lamina propria; thin layer containing layers. 50×. H&E. contains elastic fibers • Muscular layer composed of smooth muscle: § Inner circular layer § Outer longitudinal layer • Adventitia BC Higher magnification LM of the mucosa of the seminal vesicle. The honeycombed mucosa has an epithelium (arrows) composed of columnar cells and basal cells. Semen consists of spermatozoa formed in germinal epithelium of the testis and seminal fluid, the components of which are secreted by the excretory duct sytem and accessory glands. Most of this fluid is produced in seminal vesicles. 280×. H&E. High-magnification LM of the mucosa of the seminal vesicle. The epithelium is usually pseudostratified, but it may be simple columnar in places. Its height varies with age, phase of secretion, and hormonal influence. Columnar cells with eosinophilic, dome-shaped apical cytoplasm (arrows) are normally interspersed with small rounded basal cells (BC). 500×. H&E. PROSTATE PROSTATE • Production of prostatic fluid that contains prostaglandins and prostate-specific antigen (PSA). PROSTATE • Consists of 30-50 tubuloacinar (prostatic glands) glands embedded in a dense fibromuscular stroma in which smooth muscle contracts during ejaculation § The prostatic glands are lined with simple or pseudostratified columnar epithelium • Presence of Small spherical concretions called corpora amylacea in the lumens of many prostatic tubuloacinar glands • Partially calcified and eosinophilic • Increase with age (20X; H&E; Prostate) • S: fibromuscular stroma • G: tubuloacinar glands (122X; H&E; A prostatic gland) • CA: corpus amylaceum • E: secretory epithelium • LP: lamina propria • M: smooth muscle (300X; Mallory trichrome; Corpus amylaceum) • CA: corpus amylaceum • LP: lamina propria PENIS PENIS Function of penis: urination and sexual intercourse. PENIS – HISTOLOGY Two dorsal corpora cavernosa • Each of them surrounded by tunica albuginea A ventral corpus spongiosum • Surrounds the penile urethra • At the end, expands and form the glans of penis § Covered by the prepuce or foreskin • Most of the penile urethra lined with pseudostratified columnar epithelium which become stratified squamous epithelium in glans (15X; H&E; Penis) • CS: corpus spongiosum • U: urethra • CC: corpora cavernosa • TA: tunica albuginea • V: blood vessels • S: skin PENIS – HISTOLOGY Erectile tissues; consist of: • Venous cavernous spaces § Lined with endothelium § Separated by trabeculae with smooth muscle and connective tissue continuous with the surrounding tunic (100X; H&E; Penile urethra) • CS: corpus spongiosum • PU: penile urethra • UG: urethral gland • CC: corpora cavernosa • TA: tunica albuginea • HA: helicine artery (200X; H&E; Erectile tissue) • TA: tunica albuginea • SM: smooth muscle • CS: corpus spaces • HA: helicine artery