spermato and oogenesis Flashcards
(24 cards)
What is the purpose of gametogenesis?
To produce haploid gametes (sperm and ova) from diploid germ cells via meiosis.
Where does spermatogenesis occur?
In the seminiferous tubules of the testes.
What are spermatogonia?
Diploid stem cells that divide by mitosis to start spermatogenesis.
What do primary spermatocytes do?
Undergo meiosis I to form two secondary spermatocytes.
What do secondary spermatocytes do?
Undergo meiosis II to form four spermatids.
How are spermatozoa formed?
Spermatids differentiate into spermatozoa during spermiogenesis.
How many sperm are formed from one spermatogonium?
Four functional sperm.
What hormones control spermatogenesis?
FSH (stimulates Sertoli cells) and LH (stimulates Leydig cells to produce testosterone).
What is the role of Sertoli cells?
Nourish and support developing sperm cells.
Where does oogenesis occur?
In the ovaries.
What are oogonia?
Diploid stem cells that divide by mitosis in the foetus to form primary oocytes.
What do primary oocytes do?
Begin meiosis I and pause at prophase I until puberty.
What happens each month at puberty?
One primary oocyte completes meiosis I to form a secondary oocyte and first polar body.
When is meiosis II completed in oogenesis?
Only if the secondary oocyte is fertilised.
How many functional ova are formed from one oogonium?
One functional ovum and three polar bodies.
Why are polar bodies formed?
To discard excess chromosomes while keeping most cytoplasm in the ovum.
What hormones regulate oogenesis?
FSH (stimulates follicle growth) and LH (triggers ovulation and corpus luteum formation).
When does spermatogenesis start and end?
Begins at puberty and continues throughout life.
When does oogenesis start and end?
Starts before birth, continues from puberty to menopause.
How many gametes result from one germ cell in spermatogenesis vs oogenesis?
4 sperm vs 1 ovum + 3 polar bodies.
Why does oogenesis produce only one ovum?
To conserve nutrients and cytoplasm for embryo development.
Why is meiosis essential in both spermatogenesis and oogenesis?
It reduces the chromosome number to haploid, ensuring genetic stability in offspring.
What is the significance of cytoplasm retention in the ovum?
It provides nutrients and organelles for the early stages of embryonic development.
What is the role of testosterone in spermatogenesis?
Stimulates sperm maturation and secondary sexual characteristics.
