Lecture 3: Gametogenesis III

Question 1

Define Spermatogenesis

Answer 1

Development of spermatids from a primordial germ cell

Question 2

List the stages of Spermatogenesis

Answer 2

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

Question 3

Define Spermiogenesis

Answer 3

maturation of spermatozoa

Question 4

List the stages of Spermiogenesis

Answer 4

Golgi phase, Cap phase, Acrosomal phase, Maturation phase

Question 5

Where are the Cells of Leydig found, and what is their function?

Answer 5

Testis, produce testosterone

Question 6

What occurs during the Golgi phase of spermiogenesis?

Answer 6

Acrosomal vesicles formed from proacrosomal vesicles

Question 7

What occurs during the Cap phase of spermiogenesis?

Answer 7

Mature acrosome forms cap over the nucleus

Question 8

What occurs during the Acrosomal phase of spermiogenesis?

Answer 8

Sperm rotated so acrosomal pole faces wall of seminiferous tubule; cytoplasm displaced toward tail

Question 9

What occurs during the Maturation phase of spermiogenesis?

Answer 9

Flagellum formed, nuclear condensation completed

Question 10

Where are Sertoli cells found and what is their function?

Answer 10

Seminiferous tubules of testis; physical support, maintenance, coordinate spermatogenesis, secrete hormones, maintain blood-testis barrier

Question 11

Which of the following is separated from the others via the blood-testis barrier?

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

Answer 11

B. Spermatagonia

Question 12

Describe the relationship between Sertoli cells and the blood-testis barrier.

Answer 12

Sertoli cells form an immunological barrier between forming sperm cells/the rest of the body/the speratogonia

Question 13

What role does testosterone play in the function of the blood-testis barrier?

Answer 13

Stimulates the formation of a new blood-testis barrier following it’s degradation by laminin/cytokines/proteinases

Question 14

What is the role of LH and testosterone on Sertoli cells and secondary sex characteristics?

Answer 14

LH binds to Leydig cells which synthesize testosterone. Testosterone is carried to Sertoli cells via blood and to secondary sex characteristics.

Question 15

What is the relationship between FSH and Sertoli cells?

Answer 15

FSH binds to Sertoli cells and convert testosterone to estrogens, as well as synthesize Leydig stimulatory factor

Question 16

Androgen-binding protein

Answer 16

Produced by Sertoli cells, binds testosterone and carried to seminiferous vesicles

Question 17

Type A spermatogonia

Answer 17

Stem cells which can produce other type A or B spermatogonia; allows testis to continue sperm production throughout lifetime of individual

Question 18

Type B spermatogonia

Answer 18

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