Male Infertility Flashcards
Q: What is the role of the hypothalamic-pituitary-testicular axis in male reproductive physiology?
A: The hypothalamus secretes luteinizing hormone-releasing hormone (LHRH), causing the pulsatile release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. FSH stimulates seminiferous tubules to secrete inhibin and produce sperm, while LH stimulates Leydig cells to produce testosterone.
Q: What is the function of testosterone in male reproductive physiology?
A: Testosterone, secreted by Leydig cells, promotes the development of the male reproductive system and secondary sexual characteristics.
Q: What is spermatogenesis?
A: Spermatogenesis is the process in which primordial germ cells divide and undergo meiosis to form spermatozoa. It takes place in seminiferous tubules and takes about 74 days.
Q: How are mature sperm structured?
A: Mature sperm consist of a head (containing a nucleus and acrosome cap with lytic enzymes), a middle piece (containing mitochondria), and a tail (for motility). After deposition at the cervix, sperm penetrate cervical mucus and travel to the fallopian tube for fertilization.
Q: What is the definition of infertility?
A: Infertility is defined as the failure to conceive after at least 12 months of unprotected intercourse.
Q: What percentage of infertility cases are due to male factors?
A: Up to 35% of infertility cases are due to male factors.
Q: What are the common causes of male infertility?
A: Causes include idiopathic factors (25%), varicocele (40%), cryptorchidism, functional sperm disorders, erectile or ejaculatory problems, testicular injury, endocrine disorders, genetic disorders, male genital tract obstruction, systemic diseases, drug use, and environmental factors.
Q: What is the role of varicocele in male infertility?
A: Varicocele, present in about 40% of cases, can cause defective sperm development due to increased scrotal temperature and venous reflux affecting testicular function.
Q: What should be evaluated during the history of a male infertility patient?
A: Evaluation includes sexual history (duration, frequency, timing of intercourse, previous successful conceptions), developmental history (age at puberty, cryptorchidism, gynaecomastia), medical and surgical history, drug use, environmental exposures, and family history (hypogonadism, cryptorchidism).
Q: What are the key elements of the physical examination for male infertility?
A: The physical exam includes assessing secondary sexual characteristics, urogenital exam (penis, testicular consistency, tenderness, and volume), palpating the epididymis and spermatic cord, and performing a digital rectal exam of the prostate.
Q: What are the components of semen analysis in male infertility investigation?
A: Semen analysis includes measuring ejaculate volume, sperm concentration, total sperm count, morphology, and motility. WHO reference values are used as a guide for normal parameters.
Q: What hormone tests are commonly measured in male infertility investigations?
A: Common hormone tests include serum FSH, LH, and testosterone levels. In cases of low testosterone, morning and free testosterone levels are recommended. Raised prolactin may indicate pituitary disease.
Q: What is oligospermia?
A: Oligospermia is defined as a sperm concentration of less than 20 million/ml of ejaculate.
Q: What is azoospermia?
A: Azoospermia is the absence of sperm in the ejaculate.
Q: What are the causes of azoospermia?
A: Causes of azoospermia include obstructive factors (e.g., absent or obstructed vas deferens, epididymal or ejaculatory duct obstruction) and non-obstructive factors (e.g., hypogonadism, abnormal spermatogenesis, chromosomal anomalies, toxins).
