Flashcards in Lecture 3: Gametogenesis III Deck (18):
Development of spermatids from a primordial germ cell
List the stages of Spermatogenesis
1. PGCs differentiate into spermatogonia
2. Spermatogonia differentiate into primary spermatocytes via meiosis I
3. Primary spermatocytes differentiate into secondary spermatocytes via meiosis II
4. Secondary spermatocytes differentiate into 4 spermatids
maturation of spermatozoa
List the stages of Spermiogenesis
Golgi phase, Cap phase, Acrosomal phase, Maturation phase
Where are the Cells of Leydig found, and what is their function?
Testis, produce testosterone
What occurs during the Golgi phase of spermiogenesis?
Acrosomal vesicles formed from proacrosomal vesicles
What occurs during the Cap phase of spermiogenesis?
Mature acrosome forms cap over the nucleus
What occurs during the Acrosomal phase of spermiogenesis?
Sperm rotated so acrosomal pole faces wall of seminiferous tubule; cytoplasm displaced toward tail
What occurs during the Maturation phase of spermiogenesis?
Flagellum formed, nuclear condensation completed
Where are Sertoli cells found and what is their function?
Seminiferous tubules of testis; physical support, maintenance, coordinate spermatogenesis, secrete hormones, maintain blood-testis barrier
Which of the following is separated from the others via the blood-testis barrier?
C. Primary spermatocyte
D. Secondary spermatocyte
Describe the relationship between Sertoli cells and the blood-testis barrier.
Sertoli cells form an immunological barrier between forming sperm cells/the rest of the body/the speratogonia
What role does testosterone play in the function of the blood-testis barrier?
Stimulates the formation of a new blood-testis barrier following it's degradation by laminin/cytokines/proteinases
What is the role of LH and testosterone on Sertoli cells and secondary sex characteristics?
LH binds to Leydig cells which synthesize testosterone. Testosterone is carried to Sertoli cells via blood and to secondary sex characteristics.
What is the relationship between FSH and Sertoli cells?
FSH binds to Sertoli cells and convert testosterone to estrogens, as well as synthesize Leydig stimulatory factor
Produced by Sertoli cells, binds testosterone and carried to seminiferous vesicles
Type A spermatogonia
Stem cells which can produce other type A or B spermatogonia; allows testis to continue sperm production throughout lifetime of individual