Male Reproductive Histology Flashcards
(36 cards)
What are the functions of the male reproductive system?
Production, nourishment, and temporary storage of sperm
Synthesis and secretion of male sex hormone and androgens
What is the fx of the testes?
Epididymis, vas deferens, ejaculatory duct, urethra
Accessory glands (seminal vesicle, prostate gland, bulbourethral glands)
Penis
Produce sperm, synthesize and secrete androgens
Form duct system that transports sperm
Contribute fluid secretions to semen, provide nutrients to ejaculated sperm
Copulatory organ, formed of erectile tissue
What are the testis?
What suspends the testis?
What encloses the testis?
What does the thickened portion of the tunica albuginea contain?
Paired organs located in the scrotum
Posteriorly associated with the epididymus; both suspended by spermatic cord
Tunica albuginea
Mediastinum where rete testis are located
What lines the central lumen of seminiferous tubules?
Epithelium is surrounded by ____.
What is found between the seminiferous tubules?
Seminiferous epithelium: stratified epithelium; somatic columnar Sertoli cells with tight junctions interacting with spermatogonia, spermatocytes, spermatids
Lamina propria: multilayered CT, collagen, 3-5 layers of peritubular myoid
Interstitial Leydig cells
What do the stages of spermatogenesis contain?
Nuclei of spermatogonia and Sertoli cells -> closely associated with tubular wall
Spermatogonia cells (primary spermatocytes) -> larger nuclei and clumps of chromatin
Early spermatids -> round, light nuclei; close to lumen
Late spermatids -> cylindrical-shaped, condensed nuclei; close to lumen
Where are Sertoli cells?
Where is their nucleus?
What do the apical and lateral membranes provide?
Extend full thickness of the seminiferous epithelium
Nucleus is basally located with large nucleolus
Provide niches and crypts to house developing spermatogenic cells
What are the fx of Sertoli cells?
Support, protect, and nourish developing spermatogenic cells
Eliminate residual bodies via phagocytosis (discarded by spermatids during spermiogenesis)
Release of mature spermatids into lumen of tubule (spermiation)
At the basolateral domain of the seminiferous epithelium, Sertoli cells have _____ creating basal and adluminal compartments.
What are the fx of these two compartments?
Tight junctions
Basal: spermatogonial cells housed in niches; allows greater access to nutrients and signaling molecules
Adluminal: tight junctions establish the blood-testes barrier; protects developing spermatocytes and spermatids from autoimmune reactions; selects nutrients needed for spermatogenic cells
Where are the interstitial cells?
What do they produce?
Present in the intertubular space; close to blood vessels and lymphatic channels
Steroid producing cells: containing lipid droplets, mitochondria with tubular cristae; produce testosterone
Where are spermatogonial cells located?
Where do spermatogonial cells arise from?
After division, spermatogenic cells remain interconnected by ____.
Spermatogonia -> spermatocytes -> spermatids grow and differentiate ____.
Basolateral wall of Sertoli cell
Primordial germinal cell; initiates spermatogenic cell sequence or will retain stem cell capacities via mitosis; ensures continuous sperm production
Intercellular bridges (cytokinesis is incomplete)
Synchronously
What are spermatogenic cells?
Where are spermatogonia?
Diploid spermatogenic cells
Reside in a niche of basal compartment of Sertoli cells; located outside the blood testes barrier
What is the difference between type A and B spermatogonia?
Type A: clonally divides (mitosis); generate copies of itself and differentiates into Type B spermatogonia
Type B: divide by mitosis and immediately enters meiotic prophase as primary spermatocytes; ensures twice as much DNA when starting meiotic prophase I
How do spermatocytes divide?
Where are they located?
Where does meiosis occur?
Divide by two meiotic divisions
Adluminal compartment above Sertoli cell tight junctions
Inside the blood-testes barrier
Describe the meiotic divisions of spermatocyes
What happens at the end of meiosis I?
What happens at the end of meiosis II?
What initiates spermiogenesis?
Primary spermatocytes -> 1st meiotic division -> two secondary spermatocytes
Secondary spermatocytes -> 2nd meiotic division -> two spermatids (mature)
DNA content of primary spermatocytes is reduced in a secondary spermatocyte
DNA content of secondary spermatocyte is reduced again in a spermatid;
Spermatids are haploid and initiate spermiogenesis
What and where is spermiation?
Intercellular bridges that linked spermatids form ____ they are lost during maturation and _____ are separated.
What are spermatids?
Spermatids are propelled into the ____ where they undergo a ____ process; resulting in ____ for fertilization capability.
Mature spermatids are released from apical edge of Sertoli cells into lumen of seminiferous tubule
Residual bodies; mature spermatids
Nonmotile sperm released into lumen
Epididymis duct; maturation; forward motility
Where are haploid spermatids located?
Where are round (early) spermatids?
Where are elongated (late) spermatids?
Adluminal compartment, close to lumen of seminiferous tubules
Housed in niches in cytoplasm of Sertoli cells
Housed in crypts, deep invaginations in Sertoli apical cytoplasm
What cells are engaged in spermiogenesis?
Describe the process of spermiogenesis
What are released into the seminiferous tubular lumen? How?
Spermatids
Development of acrosome
Development of manchette (anchors tail)
Development of tail
Shaping and condensation of nucleus
Mature spermatids via spermiation; contractile forces generated by Sertoli cells
Describe the structure of the sperm
Head?
Tail?
Contains head and tail surrounded by plasma membrane
Head: flattened condensed elongated nucleus; anterior half of nucleus is capped by acrosome; contains hydrolytic enzymes
Tail: divided into middle, principal, and end piece (produce force needed to propel)
What is contained in the the three divisions of the sperm tail? And what is their fx?
Principal?
Middle?
End?
Principal piece: longest; has central axoneme surrounded by a fibrous sheath -> provides scaffold during sliding/bending of tail during forward motility
Middle piece: helically arranged mitochondrial sheath (ATP); axoneme; nine longitudinal columns of outer dense fibers that surround the axoneme and project down the tail
End piece: short; contains axoneme
Describe the pathway of the sperm maturation
Which part of the pathway contributes to the mesonephric duct?
Mature spermatids (immature sperm) are transported to straight tubules -> rete testis -> efferent ductules (contributes to the mesonephric duct) -> epididymal duct
Where are the straight tubules?
Describe their tissue structure
What are rete testis?
What is their histology?
Mediastinum of testis
Simple cuboidal, Sertoli cells have tight junctions at apical domain, no spermatogenic cells present
Irregularly anastomosing channels withing the mediastinum of testis
Irregularly anastomosing channels within the mediastinum of the testis
Lined by simple cuboidal, wall formed by fibroblasts and smooth m, surrounded by lymphatic channels and blood vessels and leydig cells
Seminiferous tubules drain into short, narrow ____.
Straight tubules connect to _____ network of channels embedded with blood vessels in CT of mediastinum testis
Wall of straight tubule has tall _____ that become simple cuboidal in _____.
Straight tubules
Rete testis
Straight tubule; rete testis
What is the fx of efferent ductules?
Describe the histology of efferent ductules and the fx of each cell?
Link rete testis to epididymis
Columnar cells with microvilli/ sterocilia: reabsorbs fluid from the lumen
Ciliated cells: assist in transport of nonmotile sperm
Basal cells: precursor of ciliated and nonciliated cells
Inner circular layer of smooth m underlies epithelium and basal lamina
What are the parts of the epididymis?
What epithelium lines the epididymis?
What are the specific cells and their fx?
Where are mature sperm stored?
Head, body, tail
Lined with pseudostratified columnar with long and branched stereocilia
Principal cells: columnar cells; apical domain has branches sterocilia
Basal cells: basal lamina; undifferentiated precursors of principal cells
Stored in terminal portion of the epididymal duct; sperm maturation consists in acquiring forward motility
