Lecture 19 - male reproduction Flashcards
Male gonad
testis.
components of the excurrent duct system
efferent, epididymis, and vas deferns
Gubernaculum testis
CT extending from testis in abdominal cavity to what will become scrotum, it will hold it in place until contraction and thus pulling into the scrotum
Testis and excurrent duct system embryology
from mesonephrous kidney and starts around 13 weeks. becomes efferent ducts, epididymis, and vas deferens.
3 stages in kidney development
pronephrous, mesonephrous (tubes connect during season breeding), and metanephrous.
pampiniform plexus
countercurrent heat exchange system, cools abdominal blood passing to testis and epididymis, heats blood returning from testis and epididymis to abdomen.
3 layers of testis
vaginalis viseral (single layer of cuboidal mesenchymal cells), tunica albuginea (CT, smooth muscle), tunica vasulosa (illdefined layer of CT with blood vessels which provide nutrients to the seminiferous tubules).
Mediastinum
thickening of the albuginea and creation of cavities where the seminiferous tubules empty the sperm. These then empty into the efferent duct
Leydig cells (interstitial cells)
synthesize testosterone and reside between the seminiferous tubules. Thus SER, lipid, and mitochondria with tubular cristae.
seminiferous epithelium’s 2 cell types
sertoli cells (support) and germ cells (spermatogonia, primary spermatocytes, secondary spermatocytes, and spermatids)
LH
stimulates the leydig cells to produce testosterone
FSH
stimulates sertoli cells to produce proteins for support. feedback via inhibin to regulate amount of FSH and LH from the anterior pituitary.
Testosterone’s 4 activities
maintain spermatogenesis, maintain accessory glands of reproduction, secondary sex characteristics, libido
Accessory glands that testosterone maintains
seminal vesicles and bulbourethral glands
Testosterone
cholesterol precursor. formation occurs in mitochondria and SER.
Tubules rectus
sertoli cells only (simple cuboidal) connecting the seminiferous tubules to the rete testis (simple cuboidal)
Sertoli cells
support cells that are diploid. and terminally differentiated at puberty. cytoplasm stains darker
Germ cells and its preceding stages
spermatogonium, primary spermatocyte, secondary spermatocyte, spermatids, and then elongation to a sperm
Sertoli- sertoli tight junctional complexes
blood-testis barrier (no immune system interaction), compartmentalize germinal epithelium into basal and adluminal compartment, sustenacular role (for germ cell viability)
Type A spermatogonia
stem cells (2n)
Type B spermatogonia
progenitor cells (2n)
Spermatogenesis vs spermiogenesis
spermatogenesis - entire process to create a sperm
spermiogenesis - simply differentiation from round spermatid (spermatocyte) to elongated sperm (spermatozoa).
Primary spermatocyte
after mitosis (thus 4n). Heterochromatic appearance
Spermatids
1n (rounded) which then elongate into spermatozoa.
Acrosome
head of the spermatozoa that contains the nuclear content and digestive enzymes to allow for fertilization
Middle piece
axoneme surrounded by outer dense fibers. mitochondria outside
Principal piece
axoneme with outer dense fivers and a fibrous sheath
End piece
axoneme only and covered by a plasma membrane
How long does spermatogenesis take?
64-74 days
Efferentes ducts (ductuli efferentes) and what they are lined by
roughly 20 ducts bundled together. lined by ciliated (helps moving the sperm) and absorptive cells (reabsorb fluid to concentrate sperm)
Reabsorptive cells in the efferent duct
contain large vacuoles. reabsorb fluid.
Epididymis and what it is lined by
one long duct (7m) that is highly folded and pilled upon itself. absorbs fluids concentrating sperm. lined by pseudostratified columnar epithelium with stereocilia
Cauda
widened lumen at the end of the vas deferens increases storage volume.
3 areas of the epididymis
head (caput), body (corpus), and tail (cauda)
2 main function of the epididymis
sperm maturation (prominent golgi for proteins being secreted) and fluid absorption
Vas deferens
additional layers of smooth muscle. inner and outer longitudinal and middle circular layer.
Seminal vesicle
only one tubule that is highly folded. contain simple columnar or pseudostratified columnar. secrete fluids to promote the viability of the sperm during ejaculation
Prostate location
at the base of the bladder and where the two ejaculatory ducts enter. Chestnut shaped structure
Lining of the prostatic urethra
lined by transitional epithelium
Different zones of the urethra
peripheral zone, central zone, transitional zone, and periurethral zone
Corpora amylacea
increase with age found in the prostate. simple columnar or pseudostratified columnar
Bulbourethral (cowper’s) gland
secrete mucin that 1) protects the lining of the urethral from acrosomal proteases and 2) protects sperm from remnants of urine. at the base of the penis and lines the urethra.
Histological distinct figure seen with Bulbourethral (cowper’s) gland
skeletal muscle next to alveolar gland
3 parts of the penis
root (attaches to the body wall), body (skin and dartos muscle continuation of scrotum), glans (expanded distal end)
Cross section of a penis
two corpus caveronsum (vascular spaces that fill with blood) surrounded by a tunica albuginea, urethra with a corpus songiosum.
Verumontanum
where the two ejaculatory ducts and the urethra converge in the prostate
3 components of the prostate
fibrostromal component (smooth muscle and fibroblasts), glandular component, and epithelial component.
Penile urethra lining
pseudostratified or stratified columnar
