Male Infertility 1 Flashcards

Describe the normal stages of spermatogenesis.

1
Q

What is the epidemiology for male infertility?

A
  • Approximately 15% of couples trying to achieve a pregnancy by natural means will be unable to do so within one year
  • For couples with infertility, approximately 50% have a male factor involved
  • A wide array of conditions can lead to decreased male reproductive health; the only way to appropriately evaluate the male partner is with a proper history, physical examination, and indicated laboratory testing
  • Numerous behavioral, medical, and surgical treatments are available to optimize male fertility
  • By optimizing the male partner’s reproductive potential, very often the burden of invasive treatments for the female partner can be lessened
  • Finally, male infertility is sometimes “the tip of the iceberg,” as infertility might be the only clinically apparent sign of a more important, underlying condition
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2
Q

What is the endocrinology involved in male fertility?

A
  • Integrated process involving the hypothalamus, pituitary, and testicle
  • Characterized by the actions of peptide hormones (GnRH, FSH, LH) and steroid hormones (testosterone, estradiol) on target tissue (testicle).
  • Feedback loops minimize perturbations and also help to maintain hemostasis
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3
Q

Describe the cycle of spermatogenesis.

A
  • Cycle of sperm production takes approximately 90 days
  • Wave of production arranged in a spiral configuration in the tubule.
  • Each primary spermatocyte yields 4 spermatids
  • One Primary spermatocyte(2n) → One Primary spermatocyte(4n) →Two Secondary spermatocytes(2n) → Four Spermatids(n)
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4
Q

Describe the process of spermiogenesis.

A
  • The process by which spermatids develop into mature spermatozoa
    • Acrosome is formed from the Golgi apparatus
    • Flagellum is formed from the centriole
    • Mitochondria migrate around the midpiece
    • Nucleus compacts (~10% of former size)
    • Cytoplasm extruded (cytoplasmic droplet)
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5
Q

Describe the process of sperm maturation?

A
  • Sperm maturation occurs in the epididymis.
  • Changes in surface proteins, surface charge, membrane composition.
  • Sperm acquire motility and the ability to fertilize the oocyte in the epididymis.
  • Duration of travel through the epididymis is 15 days.
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6
Q

Describe the process of fertilization from the sperm’s perspective.

A
  • Fertilization occurs in the ampullary portion of the vas deferens
  • Sperm entry into uterus facilitated by cervical mucus changes (more watery, more abundant.)
  • Sperm undergo capacitation and hyperactivation.
  • Acrosome reaction: Lytic enzymes released
  • Fertilization (sperm penetration of oocyte)
  • Zona reaction: In zona pellucida; prevents polyspermy
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