Veterinary Anatomy I - Male Reproductive Microanatomy 2024 PDF

Veterinary Anatomy I - 1555 Male Reproductive Microanatomy Rafa Sosa 2024 x3235 [email protected]...

Veterinary Anatomy I - 1555 Male Reproductive Microanatomy Rafa Sosa 2024 x3235 [email protected] The male reproductive system Testes Epididymis Accessory Ductus deferens + sex glands Penis  Testis Stroma 1 1 2 6 5 3 Bull Human 5 4 6 Visceral vaginal tunic 1. Capsule Tunica albuginea 5 2. Mediastinum testis 3. Septa 2 4. Lobe 2 3 4 1 Seminiferous t. 5. Parenchyma Interstitial tissue 6. Rete testis 3 4  Testis Parenchyma Two compartments = two functions Spermatogenesis Seminiferous tubules Ram lt. Testis Rat testis, SEM Ram testis, H&E Lateral v. Testis Interstitial tissue Steroidogenesis  Testis The seminiferous tubules - Seminiferous epithelium  Testis The seminiferous tubules - Seminiferous epithelium SERTOLI CELLS GERM CELLS (somatic cells) Seminiferous epithelium  Testis The seminiferous tubules - Seminiferous epithelium Germ cells Elongated spermatids Rounded spermatids Spermatocytes Spermatogonia Intercellular bridges Rhesus macaque spermatogonia Ram  Testis The seminiferous tubules - Seminiferous epithelium Sertoli cells -Provide physical & nutritional support to germ cells -Mediate movement of cells & molecules across the epithelium -Phagocytize degenerating germ cells -Secrete molecules into the epithelium & the interstitial tissue Ram  Testis The seminiferous tubules - Seminiferous epithelium The blood-testis barrier (BTB) Cell membrane of Sertoli cells & tight junctions between adjacent Sertoli cells -Creates two different compartments in the epithelium -Protection of germ cells (spermatocytes, spermatids & sperm) from autoimmune response -Sequestering & secreting of proteins, ions & carbohydrates that are required by specific types of germ cells Adluminal compartment Spermatocytes Spermatids BTB Basal compartment Spermatogonial stem cells Differentiating spermatogonia  Testis The seminiferous tubules - Seminiferous epithelium The blood-testis barrier (BTB) Multidirectional secretion of Sertoli cells Fructose Lactate Pyruvate Intratubular Adluminal TF compartment compartment Ceruloplasmin ABP TF = Transferrin Basal BTB compartment SCF SCF = Stem cell factor GDNF GDNF = Glial derived neurotrophic factor MIS = Mullerian inhibiting Estrogen substance Interstitial tissue & blood MIS ABP = Androgen binding vessels Inhibine protein ABP  Testis The seminiferous tubules – Tubular wall Relaxed Peritubular myoid cells Contracted Mouse (Smooth muscle) Smooth Muscle Actin -Tubular wall formation & tubule support -Contraction of tubules = flow Ram -Stimulation of Sertoli cells (PModS)* *PModS = Peritubular factor modulator of Sertoli cells  Testis The seminiferous tubules – Tubular wall Made of: Sertoli cell -Laminin -Fibronectin -Collagen Peritubular myoid cells Basal lamina  Testis The interstitial tissue Leydig cells Blood vessels Lymphatic vessels Nerves Macrophages Human Leydig cells – synthesis & secretion of androgens Ram Boar  Testis The seminiferous tubules Spermatogenesis (SSCs) n=1 Spermatocytogenesis Spermiogenesis n = 4096 Ram  Testis Sperm are carried by fluid through excurrent ducts to the epididymis Excurrent ducts – Rete testis & efferent ducts 5 1. Seminiferous tubules 2. Tubuli recti 4 3. Rete testis 5 4. Efferent ducts 3 2 5. Epididymis 1 5 Tubuli recti: simple, low columnar or cuboidal epithelium devoid of germ cells.  Testis Excurrent ducts – Rete testis & efferent ducts Rete testis Efferent ducts -Flattened channels; -Columnar ciliated cells & cuboidal ciliated cells columnar cells with microvilli -Absorption of seminiferous fluid  Epididymis -Sperm maturation: head & body a) Forward motility 5 Fibroeslatic connective tissue 4 b) Fertilization -Sperm storage: tail Sperm 2 1 Stereocilia 3 Principal cells Epididymal duct 1. Head (caput) 2. Body (corpus) Smooth muscle 3. Tail (cauda) 4. Efferent ducts 5. Ductus deferens Sperm Length (m) Basal cells Stallion 72 - 81 Pseudostratified columnar Dog 5-8 epithelium Epithelium ‘Myenteric plexus’ in Tail – ejaculation  Ductus deferens Spermatic cord 5 -Convey sperm to the 4 pelvic urethra Stereocilia 1 2 3 1. Parietal vaginal tunic 2. Visceral vaginal tunic 3. Cremaster 4. Testicular vessels 5. Ductus deferens 1 2 4 Pseudostratified columnar epithelium 5 3  Accessory sex glands Ampullary Vesicular Bulbourethral Prostate glands glands glands + + + + + + + + - + + + + - + - + - + +  Accessory sex glands Ampullary glands -Secretory epithelium = simple, tall columnar Horse -Secretion = fluid rich in fructose & ergothioneine (antioxidant aminoacid) It may become calcified: corpora arenacea -Secretion maintains sperm viability. -Function & integrity are highly dependent in testicular androgens  Accessory sex glands 2 3 Vesicular glands 1 2 Horse 1. Stroma = fibroelastic capsule (smooth muscle + elastic fibers) that extends as trabeculae 2. Secretory epithelium = simple, tall columnar Non-castrated Castrated 3. Secretion = alkaline viscid fluid rich in fructose & Highly dependent on ‘coagulating’ proteins. Sperm viability & semen testicular androgens consistency  Accessory sex glands Prostate Tubuloalveolar gland 1 3 4 2 2 1 Horse Highly dependent on testicular androgens 1. Stroma = fibroelastic capsule (smooth muscle + elastic fibers) that extends as trabeculae 2. Secretory epithelium = pseudostratified with tall columnar cells & small reserve cells (stem cells) 3. Secretion = slightly acid fluid rich in acid phosphatase, citric acid & proteins for semen ‘liquefaction’ 4. Prostatic concretions = condensed secretion, it may become calcified  Accessory sex glands Bulbourethral glands Tubuloalveolar glands 1 2 Highly dependent on testicular androgens Horse 1. Stroma = Fibrous connective tissue that sends trabeculae & is covered by striated (urethralis m.) & smooth muscle on the outer & inner surface, respectively. 2. Secretory epithelium = simple, columnar 3. Secretion = a clear viscid mucus-like fluid rich in sialoproteins & amino-sugars for urethral cleaning & lubrication before ejaculation.  Penis Musculocavernous Dog 1 1 2 4 3 5 5 3 1 2 1 4 1. Tunica albuginea = fibroelastic connective tissue 2. Cavernous bodies Musculocavernous p. = endothelial-lined spaces Fibroelastic p. = fibroelastic connective tissue 3. Spongy body =endothelial-lined spaces 4. Os penis = bone 5 3 5. Penile urethra One-health & clinical correlates Cryptorchidism Undescended testis Descended testis  One-health & clinical correlates Cryptorchidism Absence differentiating germ cells Undescended Descended Ram  One-health & clinical correlates Dog Testicular tumors Seminoma High presence of ‘germ cells’; round big nuclei & high nucleus to cytoplasm ratio Sertoli cell tumor Leydig cell tumor High presence High of cells with presence nuclei of of cells with irregular shape typical & high Leydig cell cytoplasm to phenotype nucleus ratio  Structure List 1. Testis -Stroma Tunica albuginea Mediastinum testis Septa Lobe -Parenchyma Seminiferous tubule Seminiferous epithelium Germ cells Spermatogonia Spermatocytes Round spermatids Elongated spermatids Intercellular bridges Sertoli cells Blood testis barrier Adluminal compartment Basal compartment Tubular wall Peritubular myoid cells Basal lamina  Structure List -Interstitial tissue Leydig cells -Excurrent duct system Tubuli recti Rete testis Efferent ducts 2. Epididymis Epididymal duct Principal cells Basal cells 3. Ductus deferens Muscular layer Epithelium 4. Penis Tunica albuginea Cavernous bodies Spongy body Urethra Os penis  Structure List 5. Accessory sex glands 6. Clinical correlates -Cryptorchidism -Sertoli cell tumor -Ampullary glands -Seminoma Stroma -Interstitial cell tumor Secretory epithelium Secretion Corpora arenacea -Vesicular glands Stroma Secretory epithelium Secretion -Prostate Stroma Secretory epithelium Secretion -Bulbourethral glands Stroma Secretory epithelium  Topics covered 1. The male reproductive system 2. Testis -Function -Stroma -Parenchyma -Excurrent duct system 2. Epididymis 3. Ductus deferens & testicular cord 4. Accessory sex glands -Ampullary glands -Vesicular glands -Prostate -Bulbourethral glands 5. Penis 6. Clinical correlates -Cryptorchidism -Sertoli cell tumors -Seminoma -Interstitial cell tumors References Aughey E & Frye FL 2001. Comparative Veterinary Histology with Clinical Correlates. Mescher AL 2013. Junqueira’s Basic Histology: Text and Atlas, 13rd ed. Ross et al. 1989. Histology, a Text and Atlas, 2nd ed. Samuelson DA 2007. Textbook of Veterinary Histology, 1st ed.