Lecture 22 - Male Reproduction Flashcards
each lobule of the testes has loops of
seminiferous tubules where spermatozoa mature
in the testes, sperm move through
rete testis and efferent ductules to reach the epididymis for packaging
the seminiferous tubules are composed of
sertoli cells which nurture sperm and the developing sperm are in this location
in the space around the seminiferous tubules in the testes
are leydig cells which produce testosterone
what are the 3 stages of spermatogenesis
mitosis & meiosis
packaging
where does mitotis and meiosis occur
in seminiferous tubules
when do mitosis and meiosis start
at puberty: testosterone dependent
what happens during packaging?
final maturation of sperm: acquisition of motility
where does packaging occur
epididymis
mitosis of male reproduction results in
2 diploid cells
meiosis of male reproduction results in
4 haploid cells
the midpiece of sperm contain
mitochondria
the head of the sperm contain
nucleus
mitosis occus in the
outer/basal compartment of the seminiferous tubules
meiosis occurs in the
inner/adluminal compartment of seminiferous tubule
what separates the outer/basal compartment and the inner/adluminal compartment
tight junctions aka blood-testes barrier
function of sertoli cells
nurture sperm
phagocyte defective sperm
secrete luminal fluid
during the embryonic life secrete muellerian inhibiting substance
secrete inhibin
secrete paracrine agents modulating release of T from leydig cells
respond to T and FSH
produce androgen binding protein
contain aromatase
steps of packaging
- pressure of luminal fluid within ST moves sperm towards epididymis
- in the E. most the ST fluid is reabsorbed and high T favors maturation
- 90% of semen volume derives from accessory glands
edididymis
tube of SM lined with secretory epithelium
* site of final maturation; extensive remodeling
* spermatozoa become motile
* seminiferous fluid absorbed; concentrations sperm 100 fold
* requires high T in epididymal fluids
* stored for a few days
* packaging takes about 14 days
vas deferens
- delivers sperm to abdominal cavity
- sperm stored in ampulla of vas deferens until ejaculation
accessory glands: seminal vesicles
seminal vesicles:
* empty in vas deferens
* contribute to 60% of total sperm volume
* function: dilutes sperm, provide nutrients and buffering
* composition: vit C, prostaglandins, fibrinogen, fructose buffering agents
accessory glands: prostate
prostate
* surrounds ejaculatory duct and urethra
* function: provides enzymes and factors that favor the motility, contribute to buffering
* composition: Zn, prostatic acid phosphataase, prostatic specific agents (PSA) -> indicate health of prostate
accessory glands: bulbourethral glands
bulbourethral glands
* at basis of penis
* produce a mucus-like substance prior to ejaculation
* function: clean up urethra and lubrication
FSH receptors are restricted to
sertoli cells
FSH sensitizes Sertoli cells to
testosterone
FSH also stimulates
- inhibin and ABP synthesis
- formation of tight junctions
- synthesis of seminiferous fluid
androgen synthesis occurs in
testes and adrenal gland
80% of estrogens in males derives from
T. conversion in peripheral tissues
20% of T. is converted in
E2 in testes
estrogen is involved in
formation-breakdown of bones
estrogens together with androgens mgith play a role in the growth of
prostate -> benign prostate hypertrophy
w/age, male body makes more E and more receptors for androgens in prosta
prolactin functions in males
- permissive of LH-stimulated T synthesis
- increases # of androgen receptors on accessory glands, favoring their development
high prolactin inhibits
GnRH release which then decreaes FSH/LH secretion and decreases T
andropause
reduction in testicular fxn related to age.
* decrease T
* increase LH/FSH
* decrease spermatogenesis
* starts at age 60-70
symptoms of androgen deficiency
- decreased hemoglobin
- decreased hematocrit
- muscle weakness
- decreased libido
- decreased sperm count and energy
- altered mood
- hot flashes
testosterone replacement therapy AE
- increased hematocrit/hemoglobin
- fluid retention
- prostatic enlargement
- gynecomastia
- heart attack
- obstructive sleep apnea
- possibly liver toxicity
