Flashcards in 2b Male reproductive anatomy Urethral injury Autonomic innervation of the male sexual response Seminiferous tubules Deck (21)
In order, through which structures do sperm travel (from start to finish) to complete ejaculation?
Seminiferous tubules, Epididymis, Vas deferens, Ejaculatory ducts, Nothing, Urethra, Penis (SEVEN UP)
A 67-year-old man has difficulty urinating. On rectal exam, you find an enlarged prostate. What is the likely cause of his voiding troubles?
Pressure against the bladder wall by the enlarged prostate
You examine a man and see blood at the urethral meatus. What does this make you suspicious for?
A urethral injury
A man is leaking urine into his retropubic space. What type of injury did he sustain?
Classic for posterior urethral injury
A man suffers a perineal straddle injury. Describe where urine would leak on exam.
In anterior urethral injury, urine would leak beneath the deep fascia of Buck and into the superficial perineal space if that fascia is torn
In the posterior urethra, the ____ urethra is prone to injury from pelvic fracture, and the ____ urethra is prone to injury from blunt force
The ____ (sympathetic/parasympathetic) nervous system (NS) controls erection; ____ (sympathetic/parasympathetic) NS controls ejaculation.
Parasympathetic (pelvic nerve); Sympathetic (hypogastric and pudendal nerves) (Point and Shoot)
What is the role of nitric oxide in the physiology of penile erection?
Nitric oxide is proerectile, causing smooth muscle relaxation and vasodilation via cGMP production to increase blood flow to the penis
A man comes to you with erectile dysfunction. Name the type of drug that works by affecting the nitric oxide pathway and explain how.
PDE-5 inhibitors (sildenafil) inhibit cGMP breakdown, causing an increase in cGMP, leading to smooth muscle relaxation and vasodilation
What is the effect of norepinephrine on the male sexual response?
Norepinephrine is antierectile, causing smooth muscle contraction and vasoconstriction via calcium influx to reduce blood flow to the penis
Damage to which nerves interferes with emission and ejaculation?
The hypogastric nerve (sympathetic nervous system) controls emission, and the pudendal nerve (somatic nervous system) controls ejaculation
Of the cells found in the seminiferous tubules, what are the germ cells called? The non-germ cells? The endocrine cells?
Spermatogonia; Sertoli cells; Leydig cells
A man presents with decreased sexual function and desire. He has low testosterone. What cells secrete testosterone? Where are they located?
Leydig cells secrete testosterone in the presence of luteinizing hormone; in the interstitium
What hormones and proteins do Sertoli cells produce?
They secrete inhibin, androgen-binding protein, Müllerian inhibitory factor (MIF)
What is the effect of inhibin released by Sertoli cells? Of androgen-binding protein?
Inhibits follicle-stimulating hormone; maintains the high local testosterone levels required for spermatogenesis
What forms the blood-testis barrier? What is their purpose?
Tight junctions between Sertoli cells; they isolate gametes from the immune system, preventing autoimmune attack
A man is unable to produce primary spermatocytes and maintain a sperm pool. What type of cell is likely defective here?
How do Sertoli cells and Leydig cells respond to changes in temperature?
Sertoli cells lower sperm production/inhibin release with elevated temperature (in varicocele/cryptorchidism)—Leydig cells are unaffected
What type of cell provides majority of the support and nourishment for the developing spermatozoa and regulates spermatogenesis?
Sertoli cells = Support of Sperm Synthesis
Which cells in the seminiferous tubules contain aromatase? What is the function of this enzyme?
Sertoli and Leydig cells; aromatase converts testosterone and androstenedione to estrogen