Male Reproductive Flashcards
What are the general functions of male sex organs
Endocrine- stay in body
Exocrine- leave body
Major functions of male sex organs
1 spermatogenesis
2 semen production
3 maintenance of secondary sex characteristics and libido
What is spermatogenesis
Sperm production
What is included in semen
Sperm, seminal fluid, prostate fluid
Function of seminal and prostate fluid
Lubricant
Nourishment for sperm
Buffer acidic environment of vagina
How does sperm change with age, why
Count and quality decrease
Because T levels fall with age
How does sperm cycle work
Different stages no cyclicity
70 days
What is in seminal fluid, what % of semen volume
Fructose, prostaglandins, semenogelins
60% semen volume
What is in prostate fluid, what % of semen
Citrate, zinc, PSA (alkaline)
30% semen volume
Function of testes
Sperm production in seminiferous tubules
Function of epididymis
Sperm storage for week to months- where sperm matures
Function of vas deferens
Carry sperm to urethra
Function of seminal vesicle
Adds proteins, enzymes, fructose (fructose for energy)
Function of prostate
Adds fluid, zinc (stabilize chromosomal DNA), citrate, PSA (prostate specific antigen)
Prostatic urethra location
From bladder to prostate
Seminal vesicle connects to urethra here via ejaculatory duct
Bulbous urethra location
Section after prostatic urethra Into glans
Bulbourethral gland connects to urethra here via duct
Penile urethra location
Section through the glans penis
Temperature of testes
2 degrees cooler than body
What is in intratubular compartment of testes
Seminiferous epithelium (sperm cells and Sertoli cells)
What is in peritubular compartment of testes
Connective tissue, vascular tissue, immune cells, Leydig cells
Location intratubular vs peritubular compartments of testis
Intratubular- within seminiferous tubules
Peritubular- between seminiferous tubules
What is the BTB
Blood testes barrier
Qualities of sperm after maturation
- progressive increase in forward motility
- increased ability to fertilize
- maturation of acrosome (outer layer of head)
- molecular reorganization of plasma membrane (lipids- stabilize plasma membrane, proteins- shedding and acquisition of new proteins)
- ability to bind to zona pellucida
- acquisition of receptors for proteins of the zona pellucida
- increased disulfide bonds between cysteine residues in sperm nucleoproteins
- topographic regionalization of glycosidic residues
- accumulation of mannosylated residues on the periacrosomal plasma membrane
- decreased cytoplasm and cell volume
changes to sperm during maturation
Motility
Metabolism
Morphology
Decapacitation
Maturation of sperm stages
Spermatogonia-> primary spermatocyte-> secondary Spermatocyte-> spermatid
Normal sperm count # and ejaculatory volume
60-100 million sperm per mL
3-4 mL per ejaculate
Number of sperm when infertile and % reductions of mobility and morphology
Less than 20 million per mL
Less than 50% motile
Less than 60% normal morphology
What is capacitation and where does it happen
Change sperm undergo in female reproductive tract that enables them to penetrate and fertilize an egg- acrosome reaction
Required for fertilization to occur
Happens in female reproductive tract
Name roles of Sertoli cells
- peripheral conversion of T into E2 (via aromatase)
- T and FSH required for spermatogenesis (receptors on Sertoli cells)
- high local T concentration androgen binding protein (ABP)
- secrete fluid- bathes developing sperm and aids their movement
- engulf residual bodies
- produce AMH
- produce inhibins and activins
When are testosterone levels highest and second highest in life? At what age do they tend to deplete
Highest- adult (18)
Second- in mother (3-6 months)
Deplete after senescence (after 60)
Provide example of hypothalamic-pituitary-gonadal axis using GnRH
- parvicellular neurons secrete GnRH
- action potential releases LH and FSH
- LH acts on Leydig cells to cause T production
- FSH acts on Sertoli cells to concentrate T and convert to E2 and DHT
What does LH primarily act on in males
Leydig cells
Cause T production
What does FSH primarily act on in males
Sertoli cells
Concentrate T and convert to E2 and DTH
Where is ABP produced
Sertoli cells
Why would an individual want to take anabolic steroids
Enhance protein content of muscle fibres (hypertrophy)
What do anabolic steroids do in the body hormonally
Enhance negative feedback resulting in lower LH levels and T levels (and lower intracellular T)
What do anabolic steroids do physically to the body
Enhance muscle mass but smaller testes and reduced spermatogenesis
What are the functions of T
- Maintain blood testes barrier
- Complete meiosis
- Adhere spermatids to Sertoli cells during elongation
- Release sperm into epididymis
What kind of receptors do sperm contain and why important
E2 receptors
Needed for effective spermatogenesis
Proven when men lacking aromatase have impaired sperm production and are tall (b/c E2 function in closing epiphyseal plates)
Name the 3 main feedback routes for hypothalamic-pituitary-gonadal axis
- Circulating androgens (T) inhibit pulsatile GnRH release
- Circulating androgens (T) inhibit AP
- Inhibin (Sertoli cells) inhibit AP/FSH
What location of testosterone can feedback to hypothalamus
Only plasma T (NOT TESTES T)
