11.4 Sexual reproduction (HL) Flashcards
Define gametogenesis
Process by which diploid precursor cells undergo meiotic division to become haploid gametes
What is a haploid gamete?
Sex cell
What is gametogenesis in females called?
Oogenesis
What is gametogenesis in males called?
Spermatogenesis
Where are spermatoza produced?
Seminiferous tubules of the testes
When does spermatogenesis occur?
Begins at puberty
What are the steps to spermatogenesis?
Germline epithelium cells divide mitotically to produce spermatogonia
These grow into spermatocytes which undergo mitosis and differentiation to become sperms
What is the name given to a primary spermatocyte after meiosis 1?
Secondary spermatocyte
What is the name given to undifferentiated products of meiosis in spermatogenesis?
Spermatids
When does oogenesis occur?
Begins during foetal development but is not completed until after puberty
Describe the process of oogenesis and when each step occurs
Pre-natal
Oogonia undergo growth to become primary oocytes
They begin to undertake meiosis but are arrested in Prophase I and granulosa cells surround them to form follicles
Each month after puberty
FSH triggers the continued division of some cells which will complete meiosis I to form to unequally sized cells (one polar and one with more cytoplasm)
The polar body is trapped in the follicle until it degenerates and meiosis II begins but is arrested at metaphase II
The secondary oocyte is released into the oviduct where, if fertilised, meiosis II will be completed and the mature ovum will fuse it’s nucleus with that of the sperm
What is a zygote?
An ovum with a sperm cell inside where both nuclei have fused
How many gametes are produced by spermatogenesis?
4
How many gametes are produced by oogenesis?
1 (plus 2/3 polar bodies)
In which part of the seminiferous tubules do spermatogonia grow?
Top layer of cells
What nourished spermatozoa?
Sertoli cells in the seminiferous tubules
What type of follicles are primary oocytes arrested in?
Primordial follicles
What type of follicle is the dominant follicle which ruptures to give a secondary oocyte?
Graafian follicle
What happens to the follicle after the release of a secondary oocyte?
Becomes a short-lived corpus luteum which secretes ovarian hormones and eventually degenerates to a corpus albicans