HIST AA Male Genital Lecture 2024 PDF

Form and Function 141: HISTOLOGY Male genital system Dr Mandi Alblas [email protected] Medicine and Health Sciences | EyeNzululwazi ngezoNyang...

Form and Function 141: HISTOLOGY Male genital system Dr Mandi Alblas [email protected] Medicine and Health Sciences | EyeNzululwazi ngezoNyango neMpilo | Geneeskunde en Gesondheidswetenskappe  ion Primary tis sue revis 4 Primary tissues All tissues consist of cells & extracellular matrix (ECM) A. Epithelial tissue B. Connective tissue D. Muscle tissue D. Nerve tissue  Outcomes: Male genital system 1. Identify the structure-function relationship of the male structures with regards to the: a. Testis b. Ductal system c. Glands 2. Distinguish germ cells at different steps of spermatogenesis in the seminiferous tubule, and explain which steps involve meiosis, and which involve cellular differentiation into sperm (spermiogenesis). 3. Describe Sertoli cells and Leydig cells, and explain their roles in production of sperm and regulation of male reproductive system. 4. Describe the pathway that sperm will follow from production to ejaculation. 5. Describe the histological organization of the prostate gland. 6. Annotate simple sketches (see class notes) and understand the photomicrographs Material which is made available by way of an electronic database may be subject to certain licensing conditions. These conditions normally entail that you may only use the material for your own private study and research at the University and not for any other purpose. It is expected of you to adhere to these conditions at all times. Printed material is also only made available for class discussion, private study and research purposes. Further reproduction of such material is prohibited  my Male system structure: a to An Divided into 4 major functional components: 1. Duct system 3. Accessory glands  Seminiferous tubule  2x seminal vesicles  ductuli efferentes  1x prostate gland (secrete  epididymis nutritive & seminal fluid)  ductus (vas) deferens  2x bulbourethral gland (of  ejaculatory duct (converge in urethra) Cowper) (secrete alkaline  Penile urethra lubrication) 4. 1x Penis 2. 2x Testes –organ of copulation –for production of Semen spermatozoa & Fluid expelled during ejaculation testosterone Consist of: 1. Seminal fluid 2. Spermatozoa 3. Flaked off duct lining cells  General Ducts structure: 7 Prostate 6 Ejaculatory duct 8 Prostatic ducts 5 Duct of seminal vesicles 9 Bulbourethral gland 4 Ampulla of ductus deferens 10 Cavernosum urethrae 3 Ductus deferens / vas deferens 11 Urethra 2 Ductus epididymis 1 Seminiferous tubules  Testis Septa (S) = form testicular lobules Rete testis RT = connected to epididymis Capsule = tunica albuginea (TA) Sperm pathway seminifero rete testis ductulus ductus us tubules efferente epididymis vas bulboureth prostate seminal deferen urethra ral glands gland vesicles s  y to lo g Testis Hi s Capsule = tunica albuginea (TA) = irregular dense connective tissue Groups of seminiferous tubules Seminiferous tubules divided by septa (S) = form testicular lobules Rete testis RT = connected to epididymis Epididymis (E) on posterior aspect Sperm pathway seminifero rete testis ductulus ductus us tubules efferente epididymis vas bulboureth prostate seminal deferen urethra ral glands gland vesicles s  Testis: Wall -general structure Tunica Vaginalis Double layer of mesothelium (Parietal & Visceral Layers) Carries investing layer of peritoneum Separated by serous fluid that is secreted by mesothelial cell Peritubular F: Lubrication connective F: Allows movement of testis tissue With muscle Tunica Albuginea cells Dense fibrous capsule Contains: fibroblasts, myofibroblasts F: Rhythmic contraction Give rise to incomplete collagenous septa F: Divide testis into lobules Tunica Vascularis Loose connective tissue layer Deepest F: F:Contain blood & lymphatic supply  Testis: g y Cells in seminiferous tubules o l o i st H Highly convoluted tubules Lined by: A. Germ Cells (developing gametes) – spermatogenic stages B. Non-Germ Cells - Sertoli cells: supporting cells for spermatozoa in Cross tubule section - Leydig cells: interstitial spaces  Testis: g y Cells in seminiferous tubules o l o i st H Spermatogenesis and Spermiogenesis Synchronized Sequential waves of activity Smooth Basement membrane muscle - supports basal germ layer cells - lamina propria - surrounded by myofibroblasts - spindle shaped - surrounded by fibroblasts Spermatogenesis & Spermiogenesis Spermiogenesis Spermatogenesis Spermiogenesis Spermatogenesis Spermatids transformed into Production of haploid cells via two meiosis spermatozoa cycles - Cycle 1: Duplication of chromosomes - Cycle 2: Split of chromosomes  Testis: Cells in seminiferous tubules Germ cells Spermatogonia type A Sparse cytoplasm, condensed chromatin A Always on b.m. A F: Undifferentiated germ cells, Maintain gene pool mitosis B Spermatogonia type B Sparse cytoplasm, central nucleolus mitosis F: Undergoes Mitosis, Migrate to abluminal compartment (Committed to production of 1° sperm) 1st meiosis Primary spermatocytes largest nucleus, rough chromatin, 2° F: First meiotic division 2nd meiosis Secondary spermatocytes Usually not visible under microscope 2° F: Rapidly undergo second meiosis Spermatids Small round nucleus, little heterochromatin, near lumen Looks like mature sperm-same pyknotic nucleus F:Spermiogenesis (Maturation) Mature spermatozoa  Testis: Cells in seminiferous tubules Sertoli cells Rest on basement membrane (b.m.) Highly irregular cytoplasm that constantly changing Nucleus – oval, perpendicular to b.m. Bound together by junctional complexes = Zona occludens Thus seminiferous tubule divides into 2 compartments (on outside of zonula occludens) 1. basal compartment (isolated by blood-testis barrier) (on inside of zonula occludens) 2. adluminal compartment (ad lumen= towards lumen) Testis: Cells in seminiferous tubules Sertoli cells Function of Sertoli cells: Creates blood-testis barrier Feed, support & protect developing gametes Secrete androgen binding proteins (ABP) Produce inhibin & activin Produce limited oestrogens Produce plasminogen activator needed to form plasmin for spermiation Supply fluid for transport of spermatozoa  Testis: Blood testis barrier 3. Spermatogonia type A 1. Basal compartment 2. diploid mitosis Spermatogonia type B 2. 5. 7. mitosis 3. Primary spermatocytes 1st meiosis To adluminal compartment 6. 4. Secondary spermatocytes adluminal compartment 2nd meiosis haploid 1. 5. Early spermatids 6. Late spermatids 7. Spermatozoa  Testis: Blood testis barrier Prevent exposure of gametes to immune system Formed by Sertoli cells Innermost cells (in adluminal compartment) are adluminal compartment therefore protected from cells and proteins of on inside of z.occludens immune system (present from blood in interstitium) Reason? After meiosis, the developing cells have a different combination of genes (halpoid) from Basal compartment on outside of z.occludens the rest of cells (diploid) THUS can be recognised as foreign to the body Result in an immune response against sperm cells Sertoli cells z. occludens (This does happen after trauma of testis)  Testis: Cells between seminiferous tubules Leydig cells In interstitial spaces between seminiferous tubules = endocrine cells Embedded in connective tissue between blood & lymph vessels Found either singly /in groups in supporting tissue. Secretory activity controlled by pituitary gonadotrophic hormone, luteinising hormone Function of Leydig cells: Produce and secrete testosterone  Sperm pathway seminifero rete testis ductulus ductus us tubules efferente epididymis vas bulboureth prostate seminal deferen urethra ral glands gland vesicles s  Rete testis Network of small tubes Epithelium & lamina propria simple cuboidal epithelium with microvilli F: Epithelium – resorbs protein and potassium F: Microvilli action – aid progression of spermatozoa Myoid cells F: Contracts to mix spermatozoa and to move spermatozoa to epididymis Function: helps move sperm cells from testicle to epididymis  Ductus efferente 15-20 convoluted tubules within head of epididymis Drains Rete Testis Epithelium & lamina propria Simple columnar epithelium some tall ciliated columnar. F: Ciliary action: propels spermatozoa others short, non-ciliated. F: Non-ciliary action: resorption Smooth Muscle Thin band of circularly arranged surrounding each ductulus F: aids propulsion of spermatozoa towards epididymis Function: Propels spermatozoa into epididymis  Epididymis Highly convoluted tubules Posterior aspect of testis – continuous with vas deferens Epithelium & lamina propria Pseudostratified columnar epithelium F: resorption Smooth Muscle Circularly arranged smooth muscle surrounds each ductulus F: aids propulsion of spermatozoa towards epididymis. Function of epididymis For accumulation, storage & maturation of spermatozoa Spermatozoa develop motility here  Epididymis Gradual changes in epididymis from proximal head to distal tail: Epithelium & lamina propria Head = tall pseudostratified columnar Tail = shorter pseudostratified cuboidal Each principal cell of epididymis epithelium has stereocilia. F: of stereocilia: involved with absorption of excess fluid from testis Smooth muscle increases from head to tail Proximal aspect Singular circular layer F: Slow rhythmic/ gentle movements Distal Aspect Inner/outer longitudinal (L) & Intermediate circular (C) layers F: Intense rhythmic contractility during ejaculation  Mudfix? simple epithelial layer = some tall ciliated columnar and others short and non- ciliated. pseudostratified columnar epithelial layer with stereocilia  Ductus (Vas) deferens Epithelium & lamina propria Pseudostratified columnar epithelium with long stereocilia F: Ciliary action: propels spermatozoa F: Non-ciliary action: resorption I CO Lamina propria creates longitudinal folds. LP F: permit expansion during ejaculation Smooth Muscle Very thick 3 layers Inner (I) & outer (O) longitudinal layer Intermediate circulatory (C) layer F: Produce strong pulsations Function of vas deferens Conduct spermatozoa from epididymis to urethra  Mudfix? I M O Smooth muscle layers: L C L Inner (I) longitudinal (L) smooth muscle Outer (O) longitudinal (L) smooth muscle  Accessory glands 1. Seminal vesicles (30% seminal fluid) alkaline fluid = neutralize acid from female tract 2. Prostate gland (60% seminal fluid) citrate = energy source for sperm motility enzymes = break down semen clot once in female tract 3. Bulbourethral glands (10% seminal fluid) mucus for lubrication  Prostate gland Surrounds: Neck of bladder Prostate urethra: merge with ejaculatory duct Function of prostate gland Anterolateral view Secrete citrate = energy source for sperm motility Contains prostaglandins = cause contractions of uterus in female (plays a role in transport of sperm). Enzymes = break down semen clot once in female tract Posterolateral view  Prostate gland 1. Capsule (posterolateral aspect) 2. irregular dense connective tissue with smooth muscle cells which contract during 3. ejaculation partial fibrous septa to separate gland into lobules Fibromuscular stroma (anterior-apical aspect) Collagenous connective tissue between glands Also contains smooth muscle cells Glandular tissue = consists of 3 separate groups of branched compound tubulo-acinar glands arranged around urethra in a convoluted pattern, i.e. 1. mucosal, 2. submucosal 3. main prostatic glands  Prostate gland: zones Zones: Transition – around proximal prostate urethra Central – posterior to transition zone & encircles ejaculatory ducts Peripheral – makes up bulk of gland Anterior fibromuscular stroma – no glandular tissue urethra (lies centrally, surrounded by fibrous stroma) ejaculatory ducts (lie in central stroma - towards junction with prostatic urethra)  Prostate gland Capsule (Cap) around peripheral zone (PZ) (makes up bulk of gland) urethra (U) (lies centrally, surrounded by fibrous transition zone (TZ) stroma (St)) (surrounds 1st part of prostatic urethra) central zone (CZ) (posterior to transition zone & encircles ejaculatory ejaculatory ducts (ED) (lie ducts) in central stroma - towards junction with prostatic partial fibrous septa (Sp) urethra) (separate gland into lobules)  Penis: General structure (c.s) Consist of erectile tissue Arranged in Columns Corpora Cavernosa (CC) Dorsal columns Corpus Spongiosum (CS) Ventral Column Fibrocollagenous Capsule (F) Encloses erectile tissue Within erectile tissue Enclosed in a sheet of skin (S)  Penile urethra (c.s.) Epithelium Stratified columnar epithelium (distal) Pseudostratified columnar epithelium (prox) Paraurethral Glands Mucoid secretion Lubrication Bulbourethral glands P Lubrication U penile urethra P paraurethral glands seminifero rete testis ductulus ductus us tubules efferente epididymis vas bulboureth prostate seminal deferen urethra ral glands gland vesicles s  Summary Organ Main components Cell types Functions Testis Seminiferous tubules Spermatogenic series cells Production spermatozoa Support cells for Sertoli cells spermatogenesis Interstitium Leydig cells Synthesis of androgenic hormones Rete testis Cuboidal epithelium with cilia Convey spermatozoa to ductules Smooth muscle coat efferentes Epididymis Columnar epithelium with stereocilia Store and mature spermatozoa Smooth muscle coat Vas deferens Columnar epithelium Carry sperm to urethra during Smooth muscle coat, three layers ejaculation Prostate Central, transition and peripheral Epithelium with two cell layers, luminal tall Produces secretions that mix zones & anterior fibromuscular columnar layer and basal cell layer with seminal fluid stroma Seminal Cuboidal to columnar epithelium with Produce seminal fluid vesicle muscular wall Penis Corpus spongiosum Spongy fibrous tissue containing Erectile tissue Corpora cavernosa anastomosing vascular sinuses Urethra Lined by urothelium proximally Duct for ejaculation Pseudostratified columnar epithelium distally  Summary Seminiferous Tubules Rete Testis Ductuli Efferentes Seminal Gland Epididymis Ductus Deferens Penile Urethra Prostate Gland