Lecture 3: Gametogenesis III Flashcards Preview

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Flashcards in Lecture 3: Gametogenesis III Deck (18):

Define Spermatogenesis

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


Define Spermiogenesis

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?

A. Spermatid
B. Spermatagonia
C. Primary spermatocyte
D. Secondary spermatocyte

B. Spermatagonia


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


Androgen-binding protein

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


Type B spermatogonia

Leave mitotic cycle and enter meiotic cycle under influence of retinoic acid