Gametogenesis Flashcards
How many gametes does the male and female have?
Male = 200 million per day and female = 400 in a lifetime
Which 3 processes cause genetic variation?
crossing-over, independent assortment and random segregation
Where is sperm produced ?
The walls of the seminiferous tubules
Why is the blood testes barrier important?
To prevent recognition of non-self and an immune attack on the sperm
What are the 2 types of spermatogonia?
Ad spermatogonia and Ap spermatogonia
Define the spermatogenic cycle
Time taken for the reappearance of the same stage within a given segment of tubule (16 days)
Define the spermatogenic wave
The distance between the same stage down the tubule
Define spermiation
The release of spermatids into the lumen of seminiferous tubules
What is the average volume of ejaculate?
2ml
What percentage of semen is sperm?
2-5%
What substance makes up the largest proportion of ejaculate?
Seminal vesicle secretions, amino acids, fructose, citrate and prostaglandins
What is the final stage of sperm fertility?
removal of glycoproteins and cholesterol in the female genital tract
Briefly describe the state of oocytes at birth
2 million primary oocytes have survived surrounded by a layer of follicular cells - “primordial follicles”
Name the 3 stages an oocyte goes through each month
Preantral, antral and preovulatory
What happens in the preantral stage?
Follicular cells become cuboidal and proliferate to a stratified epithelia of granulosa cells
