Downing: Male Reproductive System Flashcards
What is the major exocrine function of the testis?
production of spermatozoa
What are the major endocrine fxns of the testis?
production of androgens (testosterone) from the interstitial cells of leydig
What is the fxn of the scrotum?
thermoregulator
What is the tunica albuginea?
Dense fibrous capsule that divides the testis into LOBULES
What forms the mediastinum of the testis?
thickened portion of hte posterior aspect of the testis
What is the tunica vaginalis?
A serous sac that surrounds the anterior and lateral portions of the testis that is derived from the peritoneum.
What are hte two layers of hte tunica vaginalis?
viseral- adheres to the tunica albuginea
parietal- lines inner surface of scrotum
What is contained in the lobules of the testis?
seminiferous tubules
cells of leydig (secrete testosterone)
What do the seminiferous tubules connect with?
tubule recti
What are the two types of cells found in the seminiferous tubules?
supporting cells
germ cells
what is spermatogenesis?
spermatogonia (diploid)> spermatoza (haploid) (temp sensitive)
What are the three classes of spermatogonia?
- Dark type A= reserve stem cells
- Pale type A= renewing stem cells
- Type B= differentiating progenitors
What is the difference between primary and secondary spermatocytes?
Primary: largest germ cells, enter Meiosis I, 22 days in cycle
Secondary: 2N, short existence, rapidly enter Meiosis II (rarely seen on histological sections)
What are spermatids?
haploid progeny of mitotic divisions (nucleus condense and they migrate to lumen)
What is spermiogenesis?
maturation of spermatids to spermatoza
What are the 4 phases of spermiogenesis?
golgi
cap
acrosomal
maturation
What happens in the golgi phase?
onset of acrosome formation
axonenme assembly
What do sertoli cells look like?
extend from basement membrane to lumen
elongated nucleus
form a blood testis barrier and defines the basal vs adluminal compartments
Describe germ cell migration between sertoli cells.
B type spermatogonia traverse zonula occludens as they enter meiosis I>
cells nestle in pockets w/in a given sertoli>
progressive maturation occurs in adluminal compartment
What do FSH receptors in sertoli cells stimulate?
ABP> concentrates testosterone
Inhibitn> limits FSH production
What are the fxns of sertoli cells?
germ cell nutrition
transport of maturing germ cells to lumen
production/regulation of testicular fluid content
What lies between the seminiferous tubules?
interstitial tissue
What type of cells are located in the interstitial tissue?
Leydig cells> extensive sER> secretes testosterone
What are fertility and secondary sex characteristics dependent on?
androgens
Where does LH (ICSH) act?
receptors on Leydig cells>
stimulates androgen ouput>
feedback inhibits GnRH
Where does FSH act?
Receptors on Sertoli cells>
ABP>
promotes HIGH androgen levels in seminiferous tubule
What inhibits FSH production?
inhibin
Are leydig cells temperature sensitive?
NO
*cryptorchidism (undescended testes) has NO effect on androgen output
What do the tubuli recti do?
very short straight tubules that connect the seminiferous tubules to the rete testis
Epithelium of tulbui recti?
simple columnar
What is the rete testis?
a labyrinthine plexus of epithelial channels in the mediastinum
Epithelium of the rete testis?
simple cuboidal
Where are the ductuli efferentes?
emerge from the mediastinum on postero-superior aspect of testes
Epithelium of the ductuli efferentes?
simple columnar epithelium (alternating tall and short cells)
What is the difference between tall and short cells that form the epithelium of the ductuli efferentes?
Tall cells: ciliates (beat TOWARD epididymus)
Short cells: short microvilli (reabsorb testicular fluid)
What do the contents of the efferent ductules empty into?
ductus epididymus
What type of epithelium is found in the ductus epididymis?
Pseudostratified columnar epithelium
What allows for the peristaltic action for sperm transport in the ductus epididymis?
thin layer of circularly arranged sm muscle that surrounds the duct
What forms the ductus deferens?
very thick muscular wall that runs within the spermatic cord w/ arteires, veins, lymph vessels, nerves and the cremaster muscle
What structures are found in the ductus deferens?
Mucosa- pseudostratified w/ sterocilia
muscularis- three disting layers of smooth muscle
adventitia
What is the ampulla?
terminal dilation of the ductus deferens w/ HIGHLY folded mucosa and NO stereocilia
What is an elongated saccular organ that is located at the distal end of the ductus deferens and doesn’t fully develop until pubery?
seminal vesicle
Describe the structure of the seminal vesicle.
Mucosa: columnar epithelium, lamina propria
Muscularis: sm mucsle and external longituidinal layer of sm muscle
Adventitia: elastic connetive tissue
What secretes a yellow, viscous secretion that is rich in fructose, ascorbic acid and PGs?
Epithelium of the seminal vesicle
What is the fxn of the seminal vesicle?
contribute to volume for ejaculate
rich in fructose (principle sugar in semen and energy source of motile sperm)
What forms the prostate gland?
compound tubuloalveolar gland (30-50 glands) that surround the prostatic portion of the urethra that does NOT fully develop until puberty
What part of the prostate gland is composed of fibroelastic tissue and is RICH in sm muscle?
capsule
What makes up 1/4 of the prostate gland and is formed by dense bifromuscular tissue?
stroma
What are the three groups of glands found in teh parenchyma of hte prostate?
- mucosal glands (smallest, in periurethral tissue)
- submucosal (ring of tissue surrounding periurethral tissue, empty into urethral sinus)
- main prostatic glands (outer and largest, provide bulk of gland secretion)
What glands are related to BPH?
mucosal glands
What is the fxn of the prostate gland?
secrete thin, milky, faintly acid fluid
- especially active during sex
- dependent on testosterone
What is an indicator of potential carcinoma of prostate?
acid phosphatase
What makes up 25% of seminal fluid?
secretions from the prostate gland
What are bulbourethral glands (cowpers)?
paird bodies the size of a pea that lie in connective tissue behind the membranous urethra
*compound tubuloalveolar gland
What secretes a clear viscous lubricating material into the urethra under condition of sexual excitement?
bulbourethral glands
What secretions make up sement?
epididymal
seminal vesicle
prostatic
What part of the penis is circumsized?
prepuce
circular fold of skin covering the lgans
What forms the core of the shaft of the penis?
copora cavernosa
corpus spongiosum
tunica albuginea
Where are the corpora cavernosa located?
paired
terminate at the glans
Where is the corpus spongiosum located?
ventrall
enclose cavernous portion of urethra
end as cup shaped enlargement
What is the tunica albuginea in the penis?
thick fibrous connective tissue sheath that surrounds each of the erectile cylinders
What arteries supply the penis?
deep arteries (spiral= helcine arteries) run longitudinally through the corpora cavernosa penis
WHere are the venules of the penis located?
inner surface of the tunica albuginea
drain the cavernous spaces
What forms the deep dorsal veins?
branches of venules pierce the tunica albuginea and unite to form the deep dorsal vein
What causes an erection?
PNS stimulation> sm muscle of supplying a. to relax> vessles dilate> blood flows into cavernous spaces> lumina dilate>
How does engorgement affect the thin walled venules beneath the tunica albuginea?
compresses the venules leading to reduced venous drainage>
corpora cavernosa becomes turgid
What causes emission?
SNS
- Sm muscle of epididymis, DD and ED undergo peristaltic contractions> sperm enter urethra>
- sm muscle ins eminal vesicles and prostate contracts: seminal and prostatic fluids join sperm
What causes ejaculation?
nerve impulses form S1-S2 enter pudendal nerve>
supply skeletal muscle at BASE of erection>
increased pressure in tissue expresses semen from urethra
What is detumescence?
SNS stimulation> causes arteries to regain tone
What are hte components of the male urethra?
prostatic (transitional> stratified columnar)
membranous (stratified columanr)
penile (stratified columnar + stratified sq. NK)
What is the difference between the epidermis and dermis of the scrotum?
epidermis- more melanin present
dermis- sebaceous glands, sweat glands, hair follicles
Is there fat in teh subcutaneous tissue of the scrotum?
no (thick layer of sm muscle–dartos)
What happens to the scrotum in the cold?
dartos muscle contracts and pulls testis close to body
What happens to the scrotum when its warm?
dartos muscle relaxes and the testis descend
