Male Reproduction Flashcards
What are the functions of the male reproductive tract
Testis: sperm production and steroid hormone production
Epididymis: sperm collection and maturation
Ductus deferens: transport and storage
Accessory glands: contributions to seminal fluid
Urethra: transport
Seminiferous tubules: sperm production
Where does the majority of testosterone synthesis occur?
Leydig cells
Describe the process steroid binding to its receptor
Steroid bind to receptor
This produces a complex that acts on DNA
Binding of the complex to sites on DNA alters the the genes being expressed by target cells
Describe the process of androgens binding to their receptor
Androgens interact with AR - all major cell populations in the testis, epididymis and accessory glands express AR
Androgen-AR binding is needed in sperm production, transport and activation
Why are androgens important?
They are responsible for the development of secondary sex characteristics, anabolic effects and spermatogenesis
Describe the HPO axis for the production of spermatozoa and sex steroids
Hypothalamus stimulated to secrete GnRh which acts on the anterior pituitary to stimulate the secretion of LH and FSH which have their effect on the testis to produce spermatozoa and sex steroids
Describe gonadotropin action in the testis
Androgen binding protein (ABP) binds to testosterone and DHT and concentrated them in the luminal fluid of the seminiferous tubules and downstream regions f the male tract
What does ABP binding stimulate?
Spermatogenesis in the seminferous tubules
Spem maturation in the epididymis
Accessory gland secretions
Myoid cell contractile activity to propel sperm along the tract
Describe the process of spermatogensis
Maturation stages are androgen-dependent
Myoid cell contractility is required to to move released sperm along the seminiferous tubule
Myoid cells are AR positive, action is androgen-dependent
At the point of release of sperm into the lumen of the tubule, sperm are not yet motile
The ability to swim is initially acquired in the epididymis with further activation in the female tract
Describe the composition of semen
Volume of ejaculate: 1.5-5.0ml
Sperm count: 40-250 million/ml
Leukocyte count: 0-200/ml (indicative of UTI)
How does an erection occur?
Erectile tissue becomes engorged with blood, arterioles dilated as a result of parasympathetic nervous system activity
What are the causes of erectile dysfunction?
Pathological causes: psychogenic, neurogenic, vascular and endocrine
Latrogenic causes: drugs such as SSIRs, tricyclics, antihypertensives
What are the symptoms of prostate cancer?
Urgent and frequent urination
Nocturnal enuresis
Difficulty starting or emptying the bladder
Urine flow weak, interrupted or difficult to control
Back/pelvic pain
What is the treatment for prostate cancer?
GnRH agonists and antagonists
Androgen antagonist: cyproterone acetate
5⍺ reductase inhibitors: dustasteride and finesteride
Give a use of anabolic steroids
Treatment of some aplastic anaemias