Gametogenesis, spermatogenesis, spermiogenesis

Question 1

What is Fertilization?

Answer 1

Male and female gametes fuse giving rise to the formation of the zygote…

Question 2

What is Zone Pellucida (ZP)?

Answer 2

Specialized extracellular matrix (ECM) which is produced by the oocyte and follicular granulosa cells

Question 3

4 main glycoproteins of Zona Pellucida

Answer 3

ZP1, ZP2, ZP3, ZP4

Question 4

Functions of Zona Pellucida in general

Answer 4

protection, transport, sperm binding, prevention of polyspermy, support of blastocyst development, prevention of early implantation

Question 5

Function of Zona Pellucida (specifically)

Answer 5

required for structural integrity of the matrix, minimize precocious hatching

Question 6

Function of ZP1, ZP3 and ZP4

Answer 6

binds to the capacitated human spermatozoa

→ induce acrospmal reaction

Question 7

Function of ZP2

Answer 7

Sperm recognition receptor

Important role in defence against polyspermy.

Question 8

How can play an important role in defense against polyspermy?

Answer 8

It is cleaved by ovastacin released from cortical granules after fertilization and other sperm can not bind to the oocyte

Question 9

What is Gametogenesis?

Answer 9

the conversion of germ cells into male and female gametes

Question 10

Primordial germ cells (PGCs) give rise to ___ (2 type of cells)

Answer 10

Sperm cells and Oocytes

Question 11

What happen during prenatal events of Gametogenesis?

Answer 11

• Primordial germ cells develop from epiblast during the second week
  
  • → appear in the wall of the yolk sac at the end of the 3rd week of development
• Germ cells migrate from the yolk sac toward the developing gonads (primitive sex glands)
  
  • → arrive at the end of the 4 th or the beginning of the 5 th week

Question 12

What is Spermatogenesis?

Answer 12

the sequence of events by which spermatogonia are transformed into mature gametes: sperm (spermatozoa).

Question 13

3 events occur during spermatogenesis

Answer 13

1. Spermacytogenesis
2. Meiosis
3. Spermio(histo)genesis

Question 14

What is Spermatocytogenesis?

Answer 14

Asymmetric division of spermatogonia.

(Some of them remain „stem cell”, others start the differentiation process.)

Question 15

What is Spermio(histo)genesis?

Answer 15

spermatids are transformed to sperm that can fertilize eggs

Question 16

3 main events of spermatogenesis?

Answer 16

1. Spermatocytogenesis : asymmetric division of spermatogonia. Some of them remain „stem cell”, others start the differentiation process.
2. Meiosis: meiotic division of spermatocytes (I and II)
3. Spermio (histo)genesis: spermatids are transformed to sperm that can fertilize eggs

Question 17

How can spermatogonia become spermatids?

Answer 17

Spermatogonia

→ mitosis, growth

→ primer spermatocytes

→ first meiotic division

→ secunder spermatocytes

→ second meiotic division

→ spermatids

Question 18

4 main events of Spermiohistogenesis

Answer 18

(transformation of spermatids into spermatozoa)

(a) Formation of acrosome cap (lysosome-hydrolytic enzymes foracrosomal reaction of fertilization)
(b) Condensation and elongation of the nucleus
(c) Development of flagellum (formation of neck, middle piece and tail)
(d) Shedding of most of the cytoplasm

Question 19

Where are male germ cells?

Answer 19

in the sex cords of the testis

Question 20

Which cells are supporting male germ cells (PGCs)? Where are they derived from?

Answer 20

The supporting cells are derived from the surface epithelium of the testis and become Sustentacular/Sertoli Cells