Male Reproductive Histology Flashcards
each testis is covered by a visceral layer of _______ and reside in a _______ lined by a parietal layer of _________
each testis is covered by a visceral layer of processus vaginalis and reside in a serous cavity lined by a parietal layer of processus vaginalis
processus (tunica) vaginalis: out-pouching of the peritoneum that leads the descent of each testis
tough, fibrous capsule surrounding each testis
tunica albuginia (“white tunic”)
at the posterior end this is thickened to form the mediastinum testis, from which septa extend to divide testis into lobules
what is contained in each testis lobule?
1-4 seminiferous tubules - site of sperm production
solid cords until puberty when they acquire a lumen
loose, highly vascular connective tissue surrounding the testis
tunica vasculosa - deep to the fibrous tunica albuginia and continuous with the vascular connective tissue surrounding the seminiferous tubules
which cells are found in small clusters in the vascular connective tissue surrounding the seminiferous tubules?
Leydig interstitial cells - secrete androgens
what are the layers of the testis from superficial to deep? (3)
- tunica albuginia
- tunica vasculosa
- seminiferous tubules (containing Leydig cells)
seminiferous tubules are lined with these 2 populations of cells:
- germinal epithelium - site of spermatogenesis
- Sertoli cells - “nurse”/supportive cells
outermost layer is 3-5 layers of peritubular myoid (contractile) cells
order the following from the lumen of the seminiferous tubules moving outwards: spermatogonia, primary spermatocytes, Sertoli cells, spermatids
- spermatids (innermost)
- primary spermatocytes
- Sertoli (“nurse” cells - larger and more pale)
- spermatogonia (outermost, stem cells)
the blood-testis barrier is made of _____ and separates which 2 populations of cells?
blood-testis barrier: made of Sertoli cell cytoplasmic processes (form occluding junctions), separates spermatogonia (basal compartment) from primary spermatocytes (adluminal compartment)
what are the 4 phases of spermiogenesis?
- Golgi phase - hydrolytic enzymes sorted, centrioles migrate
- Cap phase - acrosome sac flattens
- Acrosomal phase - distal centriole gives rise to axoneme, mitochondria migrates
- Maturation phase - outer dense fibers of Keratin develop along the axoneme
this produces immobile spermatozoa not yet capable of fertilizing an egg
[Guys Can Always Mature]
what causes Kartagener’s syndrome?
aka immotile cilia syndrome: inherited disorder in which cilia lack dynein
—> infertility (males), chronic sinusitis and bronchitis
during spermiogenesis, maturing spermatids are embedded in…
… cytoplasm of the Sertoli cells
what are the functions of the following hormones secreted by Sertoli cells?
A. Activin
B. Inhibin
C. Androgen binding proteins
D. Mullerian inhibitory substance
A. Activin: promotes the release of FSH (—> increased spermatogenesis)
B. Inhibin: suppresses the release of FSH
C. Androgen binding proteins: essential for keeping the level of testosterone higher inside the seminiferous tubules relative to outside
D. Mullerian inhibitory substance: suppresses müllerian duct development (female)
On which male reproductive cells does luteinizing hormone act and what is its function?
LH from the anterior pituitary stimulates the interstitial cells of Leydig to produce testosterone
therefore, it makes sense that Leydig cells are found near blood supply
it also then makes sense that Leydig cells contain lipid droplets for steroid hormone production
what is the skeletal vs smooth muscle of the testis called?
skeletal = Cremaster
smooth = Dartos
The testicular arteries are surrounded by what plexus?
Pampiniform venous plexus – important for countercurrent heat exchange (spermatogenesis is temperature sensitive)
name the structures of the male reproductive duct system, beginning with the seminiferous tubules and ending with the urethra (8)
- seminiferous tubules
- straight tubules
- rete testis
- efferent ductules (beginning of extra-testicular ducts)
- epididymis
- ductus (vas) deferens
- ampulla (storage of spermatozoa)
- ejaculatory duct
8 urethra
what happens to spermatozoa as they move through the epididymis?
Acquire motility + surface associated proteins that will ultimately be removed in the female reproductive tract
what are the parts of male urethra? (3)
- prostatic
- membranous
- penile (spongy)
what type of epithelium is found in the seminal vesicles and why does this make sense?
Columnar with goblet cells – produce thick seminal fluid that is rich in fructose, serves as a source of nutrition for sperm
Seminal fluid constitutes about 70% of semen
What is the function of the male reproductive structure found immediately inferior to the bladder and immediately superior to the urogenital diaphragm?
prostate gland - contributes essential secretions to semen which maintain sperm viability
urethra passes through the prostate gland and is joined by the ejaculatory ducts
what are the three types of cells found in the prostatic epithelium?
- Secretory cells – vary from cuboidal to columnar and produce prostatic fluid.
- Basal cells – stem cells to renew secretory epithelium.
- Neuro endocrine cells – function unknown.
what are the three zones of the prostate gland?
- Transition zone: surrounds the urethra, enlargement commonly gives rise to benign prosthetic hyperplasia and ~20% of prostatic cancers originate here
- Central zone: contributes about 25% of glandular tissue
- peripheral zone: ~70% of glandular tissue and ~70% of prostatic cancers arise here
From which zone of the prostate do most prosthetic cancer is arise?
peripheral zone – makes up most of the glandular tissue
What is the function of the bulbourethral/Cowper’s glands?
paired glands found in the urogenital diaphragm that secrete mucus into the penile urethra at the start of sexual arousal for lubrication
what is the function of the urethral glands of Littre?
microscopic glands found in penile/spongy urethra that secrete glycosaminoglycans that protect the epithelium from urine
Can become inflamed (urethritis), site of gonorrhea infections
