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
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
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)
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)
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.
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