Spermatogenesis Flashcards
Gametes in males are called
Spermatozoa (sing. spermatozoon)
What is spermatogenesis?
Gametogenesis in males
What are gametes in females called?
Oocytes
Gametogenesis in females is
Oogenesis
What is different about oogenesis
Differentiation occurs before birth from cells called oogonia
Where and when does spermatogenesis occur?
occurs in the testes after puberty (12- 14 years)
What 2 hormones influence spermatogenesis?
- Follicle stimulating hormone (FSH)
2. Testosterone
What are the 3 sub-divisions of spermatogenesis?
- Spermatocytogenesis
- Spermatidogenesis
- Spermiogenesis
What is the optimum temperature for spermatogenesis?
2-3℃ below body temperature ( 37℃)
Where are the testes located and why?
They are located in the scrotum below the pelvis outside the abdomen because optimum temperature for spermatogenesis is less than normal body temperature
What’s the duration of spermatogenesis?
It is continuous throughout post-pubertal life
At what age does spermatogenesis peak?
25 years
How many spermatozoa are produced per testis a day at peak?
150,000
What occurs during spermatocytogenesis?
It is repeated mitotic divisions that convert Type A pale spermatogonia to primary spermatocytes.
Where does spermatocytogenesis occur?
In the abluminal compartment in the seminiferous tubule (external to the blood-testis barrier)
How long does spermatocytogenesis take?
16 days
What kind of cell division process occurs in spermatidogenesis?
Meiosis
What are the two steps in spermatidogenesis?(make refers to cell numbers)
- First part of meiotic division from primary spermatocyte to 2 secondary spermatocytes.
- Second part of meiotic division of 2 secondary spermatocyte to 4 spermatids.
What does chiasmata between 2 homologous chromosomes produce?
Unique chromosomes
Why are spermatids haploid?
Because meiosis halves the DNA and chromosome numbers.
Where does spermatidogenesis occur?
In the adluminal compartment of the seminiferous tubule (internal to the blood-testis barrier)
What is spermiogenesis?
It is the conversion of spherical spermatids to tadpole shaped spermatozoa.
What are the 5 major events in spermiogenesis?
- Nuclear morphogenesis and condensation
- Formation of tail
- Formation of acrosome
- Rearrangements of mitochondria and centrioles
- Shedding of excess cytoplasm
Where does spermiogenesis occur?
In the adluminal compartment of the seminiferous tubule
What is the importance of flagellum in the tail of the spermatozoa?
Self-propulsion
How long does spermiogenesis take?
24 days
How long does the entire spermatogenesis process take?
64 days
How long does spermatidogenesis take?
24 days
