Topic 49 Spermatogenesis and ovogenesis. Ovulation
Covers gametogenesis in both sexes, then spermatogenesis in three phases from spermatogonia through spermiogenesis to the mature sperm, with the structure of mature sperm. It describes Sertoli and Leydig cells and their secretions, the hormonal and external factors regulating spermatogenesis, and oogenesis with follicular development. It ends with ovulation and the corpus luteum and corpus albicans.
Topic 49 of 59 in the MU Pleven syllabus for Cytology (Medicine, Year 1). The free AceMed note covers it in 6 sections, about 386 words (3 min of reading), with 29 flashcards.
In this note
Topic 49 Spermato- and ovogenesis. Ovulation
Gametogenesis
Spermatogenesis
Oogenesis
Ovulation
Corpus luteum & corpus albicans
Gametogenesis
In both sexes, primordial germ cells (PGCs) undergo mitotic divisions within the gonads → then commence gametogenesis, converting into spermatozoa or definitive oocytes.
Includes:
Meiosis → reduces chromosome number.
Cytodifferentiation → maturation into functional gametes.
Spermatogenesis
Process by which spermatogonia develop into sperm.
Begins shortly before puberty (pituitary gonadotropins influence) and continues throughout life.
Divided into 3 phases:
Spermatogonial phase (mitosis):
Type A dark (Ad): ovoid nuclei, dark chromatin.
Type A pale (Ap): light nuclei, actively divide.
Type B: spherical nuclei, clumped chromatin → produce primary spermatocytes.
Spermatocyte phase (meiosis):
Primary spermatocytes → meiosis I → secondary spermatocytes.
Secondary spermatocytes → meiosis II → haploid spermatids.
