L21 - Histology of the Male Reproductive System Flashcards
Tract the drainage of sperm in the testis?
Seminiferous tubule > Straight tubule > Rete testis > Efferent ductules > Epididymis
Describe the internal organization of testis?
Tunica albuginea = thick connective tissue capsule surrounding testis
Extensions of t. albuginea form septa: separate lobules
Describe the lining and function of seminiferous tubules in testis?
1-4 coiled tubes in each lobule:
- Lined by Stratified Germinal epithelium
- Location of spermatogenic cell division, maturation and transform into sperm
Function of the Vas deferens?
- Connect epididymis to ejaculatory duct
- Strong smooth muscle contraction expel sperm during ejaculation
Define the brief functions of each accessory gland in male reproductive tract?
- Bulbourethral gland = lubricating mucus secretion, neutralize vaginal acidity
- Prostate = proteolytic enzyme to breakdown clotting factors in ejaculate for sperm fluidity
- Seminal vesicles = most of semen secretion, rich in fructose, ions, anti-oxidants…etc
Define the erectile tissue in penis?
three masses of erectile tissue:
- paired corpora cavernosa
- corpus spongiosum
Define the epithelium and cell type in: Seminiferous tubules
Stratified Germinal epithelium (thick)
Surrounded by thin layer of connective tissue
Sertoli cells + spermatogenic cells sit on thick basal lamina
Define the epithelium and cell type in: Straight tubules and Rete testis
Simple cuboidal epithelium
Lined by sertoli cells and simple cuboidal cells with short microvilli and single flagellum
Define the epithelium type in: Efferent ductules
Columnar epithelium with cilia
Define the epithelium and cell type in: Epididymis
Pseudostratified columnar epithelium with stereocilia
Principal cells with stereocilia, surrounded by Basal cells and smooth muscle
Define the epithelium and smooth muscle type in: Vas deferens and ejaculatory duct
Pseudostratified columnar epithelium with stereocilia (like epididymis
3 layers of smooth muscle:
- Inner longitudinal
- Circular intermediate
- Outer longitudinal
Define the epithelium type in: Seminal vesicles, prostate and Bulbourethral glands
glandular epithelium
Define the epithelium type in: Urethra?
transitional epithelium
→ pseudostratified or stratified columnar
→ non-keratinzed stratified squamous epithelium
Type of structural connective tissue in testis?
- Tunica albuginea: dense, irregular connective tissue
- invaginate and continues as Interlobular septa and Mediastinum testis
Type of cell found in interstitium of testis?
In connective tissue: Leydig cells and Myofibroblasts
Which cells have Reinke crystals in testis?
Leydig cells
Define the cell types in seminiferous tubules?
Germinal epithelium:
Sertoli cells + Spermatogonia
Describe the process of spermatogenesis in seminiferous tubule in testis?
1) Spermatogonium diploid (2n)
2) Develop into primary spermatocyte
3) a primary spermatocyte generates two secondary spermatocytes
4) Two haploid spermatids (haploid cells) are generated by each secondary spermatocyte, total = four spermatids
5) Spermiogenesis (maturation) into spermatozoa
Function of Sertoli cells?
Partially envelop germ cells:
- Support, protect and nourish spermatogenic cells
- Phagocytose cytoplasmic remnants of spermatids
- Signalling germ cells, Leydig cells
- Establish the blood-testis barrier****
What cell provides the testis with immunological previledge?
Sertoli cells form adjacent tight junctions near basal lamina of seminiferous tubule > blood-testis barrier
Describe how sertoli cells continue to provide protection for developing spermatocytes moving into lumen of seminiferous tubule?
New tight junctions continue to form behind moving spermatocytes»_space; continue to envelop
Describe the cell types and structure of the interstitium of testis?
Interstitium = space between basal lamina and adjacent seminiferous tubules
Leydig cells, Fibroblasts, mast cells, macrophages
Rich in collagen
How do seminiferous tubules increase sperm expulsion?
Outer wall of seminiferous tubules have myoid cells
> > contraction to propel sperm to lumen
Location and function of Leydig cells in testis?
Dispersed in clusters through interstitial tissue between seminiferous tubules
Synthesis of testosterone
Histological appearance of Leydig cells?
Large round nucleus
Abundant sER and Golgi
Contains crystals of Reinke
What do efferent ductules connect in testis? Function?
pierce tunica albuginea to carry sperm from rete testis to epididymis
Resorb most luminal fluid secreted by the Sertoli cells
Ciliated columnar cells move the spermatozoa
Define the secretions by Seminal vesicles?
- fructose (provide energy),
- ascorbic acid, (antioxidant),
- stimulators of sperm motility: potassium, bicarbonate, magnesium, prostaglandin,
•semenogelin:coagulum formation, inhibit sperm capacitation and motility
Describe the epithelium of seminal vesicles?
Glandular epithelium:
- Highly convoluted/ invaginated, irregular epithelium
- Supported by extensive lamina propria
- 2 layers of Muscularis: inner circular, outer longitudinal
- Adventitia
Describe the epithelium in prostate?
Glandular epithelium:
- Simple columnar cells arranged in glandular acini, surrounding large irregular lumen
- Fibromuscular stroma extend throughout
- Dispersed Prostatic concretions
What marker is used to Dx Benign prostate hyperplasia? Which zone of prostate secretes this?
PSA
Transitional zone: anterior to Periurethral gland zone
Describe the epithelium in Bulbourethral (Cowper’s) gland?
Tubular alveolar glands:
Simple columnar cells arranged in acini with large, irregular lumen
Function of Bulbourethral gland secretion?
slippery, mucous fluid which lubricate the urethra + tip of penis
Neutralize any acidity from residual urine in the urethra + acidity of the vagina
Anatomical location and opening of the Bulbourethral glands?
At roof of penis, embedded in muscle of urogenital diaphragm
Excretory duct terminate at proximal penile urethra
Define the 3 erectile tissue in penis?
Corpus cavernosum
Corpus spongiosum
Define the histological layers of the penis from superficial to deep?
- Superficial fascia (Colles’ fascia)
- Deep fascia (Buck’s fascia)
- Tunica albuginea
- Erectile tissue:
i) Paired Corpus cavernosum with deep artery of penis at center
ii) Corpus spongiosum with urethra in center
Epithelium of erectile tissue of penis?
Irregular vascular spaces with vascular epithelium
Define the 6 layers of the scrotum
- Skin
- Dartos muscle and fascia
- External spermatic fascia
- Cremasteric muscle
- Internal spermatic fascia
- Parietal and visceral Tunica Vaginalis
Describe the epithelium, epidermis and dermis of skin at scrotum?
epithelium: thin, corrugated and pigmented;
epidermis: keratinized squamous epithelium
dermis; divided in half by a midline cutaneous raphe
Describe the function and structure of Dartos muscle and fascia in scrotum?
two coherent plexuses of smooth muscle cells;
contracts in cold or during sexual stimulation
Which layer of the scrotum carry oblique muscles?
External spermatic fascia: continuation of external oblique aponeurosis
Cremasteric muscle: bundles of skeletal muscle, continuation of internal oblique muscle
What does the internal spermatic fascia connect?
Attach transversalis fascia to tunica vaginalis
