Histology of the Male Reproductive Tract Flashcards
Sertoli cells are supportive cells that are predominant before puberty. What is one of the major functions of this cell type?
Provide crypts for developing spermatogenic cells
What is the site of spermatogenesis?
The seminiferous tubules
What are the three regions of the seminiferous tubules?
Seminiferous epithelium
tunica propria
Interstitium
What are the cells of the seminiferous epithelium?
–Sertoli cells
–Spermatogenic cells
What are the cells of the tunica propria of the seminiferous tubules?
Myoid cells
What are the cells of the interstitium of the seminiferous tubules?
Leydig Cells
What are the distinct characteristics of Type A spermatogonium (Sa)?
Large round or oval nucleus. Found closest to the basal lamina.
What are the distinct characteristics of the Type B spermatogonium?
- Dispersed chromatin with prominent nucleolus
- Further from basal lamina
What are the sperm cells found in the adluminal compartment? Describe them.
–Primary spermatocyte (S1)
•Large nucleus with clumps or threads of chromatin
•Copius cytoplasm
–Secondary spermatocyte (S2)
•Rapidly dividing therefore not see
What sperm cells are near the lumen? Describe them
–Spermatid (S3)
•Dense, round nucleus
–Spermatozoon (S4)
•Dense, pointed nucleus
What are the distinguishing characteristics of the sertoli cells?
–Triangular or ovoid nucleus with prominent nucleolus and dispersed chromatin
What are the phases of spermatogenesis?
- Spermatogonial phase
- spermatocyte phase
- spermatid phase
What happens in the spermatogonial phase?
- Undergo mitosis
- Replenish germ cell population (Type A)
- Create committed spermatogonia that will differentiate (Type B)
What happens in the spermatocyte phase?
- Undergo meiosis
- Primary spermatocytes (4n) undergo first meiotic division
- Secondary spermatocytes (2n) undergo second meiotic division
- Create spermatids (1n)
What happens in the spermatid phase?
- Undergo spermiogenesis
- No further division, just maturation
- Extensive cell remodeling to mature spermatozoa
What do myoid cells secrete? What do they promote?
•Collagen secreting
•Contractile to promote peristalsis
–Sperm non-motile at this point
What is the clinical correlate regarding peritubular cells?
AKA Myoid cells
Thicken with aging, associated with infertility
What do Leydig cells produce? When are they active?
•Androgen-producing
–Primarily testosterone
–Normally, resembling fibroblasts and inactive from birth to puberty
What are the key histological features of Leydig cells?
•Polygonal, eosinophilic
•Abundant sER
•Contain lipid droplets
•Sometimes present in cytoplasm:
–Lipofuscin
–Crystals of Reinke
»Rod-shaped cytoplasmic protein deposits
»Unknown function
What are the components of the intratesticular ducts?
Straight Tubules (tubuli recti)
Rete Testes
What cell types are found in the straight tubules? What is this section of the intratesticular ducts?
- Short ,terminal portion of seminiferous tubules
- Sertoli cells only transitioning into cuboidal epithelium
The Rete testes are anastamosing channels of simple cuboidal or low columnar epithelium. What are two key characteristics of this portion of the intratesticular ducts?
Apical cilia and microvilli
What are the the four components of the male reproductive system?
- Testes
- Excurrent Duct System
- Accessory Glands
- Penis
What are the components of the excurrent duct system?
–Epididymis
–Vas deferens
–Ejaculatory duct
–Urethra
What are the components of the accessory glands?
Seminal Vesicle
Prostate
Bulbourethral glands
What do the efferent ductules do? What tissue types are these similar to?
–Drain rete testes into epididymis
–Transitional but similar to epididymal epithelium and smooth muscle
The epidydimus is a long, convoluted duct. What is its function?
–Function is to accumulate and store spermatozoa for maturation
What does the epidydimus consist of?
•Smooth muscle
–Increases from one to three layers as it moves distally
•Pseudostratified columnar epithelium
–Prinicipal cells
»Decrease in height as it moves distally
»Contain stereocilia
•Long microvilli
–Basal cells
»Small, round stem cells at basal lamina
What does the vas deferens do?
–Conducts spermatozoa from epididymis to urethra
The ductus deferens is a thick walled muscular tube, what does it consist of?
•Smooth muscle
–Inner and outer longitudinal layers
–Intermediate circular layer
•Pseudostratified columnar epithelium
–Closely resemble epididymis
–Contains longitudinal folds for expansion
What is the ejaculatory duct the combination of? What does it travel through?
The vas deferens and the duct of the seminal vesicle.
Travels through the prostate
The seminal vesicles are paired highly folded tubular glands that secrete 85% of seminal fluid volume. What are the three main components of this structure?
smooth muscle
mucosa
fibrous coat
Describe the mucosa of the seminal vesicle!
What does the prostate gland secrete?
–Secrete alkaline fluid that contributes the other 15% of seminal fluid volume
The prostate is a combination of 30+ tubuloalveolar glands. What are the glandular components?
Glandular Epithelium
Lumen
Describe the cells of the prostate glandular epithelium.
–Glandular epithelium
»Thrown into folds
»Tall columnar cells
•Basal nuclei
•Pale-staining cytoplasm with vacuoles
»Basal cells
How can you easily identify the lumen of the prostate gland?
»Corpora amylacea (prostatic concretions)
•Calcified cellular secretions
•May appear lamellar
(Ball sand?)
What is the prostate stroma composed of?
–Fibromuscular (collagen and smooth muscle)
What are the four anatomical zones of the prostate gland?
- Transitional zone
- central zone
- peripheral zone
- anterior fibromuscular stroma
What does the transitional zone of the prostate surround? What do we see arise here?
–Surrounds prostatic urethra (5%)
–Most benign nodular hyperplasia arise here
What is the most obvious sign of benign nodular hyperplasia arising in the transitional zone?
Compression of the urethra.
What does the central zone of the prostate surround?
Ejaculatory duct
What is the bulk of the prostate gland? What arises here?
–peripheral zone (70%)
–Most cases of carcinoma arise here
What kind of glandular tissue is found in the anterior fibromuscular stroma? Describe the capsule that surrounds this structure.
–Contains no glandular tissue
–Only part not enclosed by capsule
What are the components of the penis?
- Corpora cavernosa
- Corpus spongiosum
- tunica albuginea
- skin
What are the corpora cavernosa?
Two dorsal masses of erectile tissue
What is the corpus spongiosum?
–One ventral mass of erectile tisse
–Penile urethra embedded here
What is the tunica albuginea of the penis?
–Fibroelastic capsule around the three erectile tissue masses
Erectile tissue is composed of wide, irregularly shaped vascular sinuses. What is it lined by? Surrounded by?
- Lined with vascular endothelium
- Surrounded by fibrocollagenous stroma with irregular smooth muscle bundles
Where are helicine arteries found? What are they?
In erectile tissue.
•Thick-walled anastomosing arteries and arterioles
What tissue is the urethra composed of?
–Primarily stratified or pseudostratified columnar epithelium
What are the three parts of the urethra?
•Penile urethra (spongy urethra)
–Highly convoluted
•Prostatic urethra
–Transitional epithelium
•Urethral meatus (external opening)
–Stratified squamous epithelium
What do the paraurethral glands do?
- Mucoid secretions for lubrication
- Simple coiled tubular glands
Describe the bulbourethral glands. What do they secrete?
- Pea-sized structure at initial portion of penile urethra
- Mucoid secretions for lubrication
- Compound tubuloalveolar
