Gametes + HPG axis Flashcards
Describe the appearance of chromosomes in the prophase stage of meiosis.
Condense + become visible
Describe the appearance of chromosomes in the metaphase stage of meiosis.
Line up in pairs in the centre, along the metaphase plate
Describe the appearance of chromosomes in the anaphase stage of meiosis.
Pulled to the opposite sides of the cell
What is the chiasmata?
Sites where crossing over between chromatids occurs
What pulls chromosomes to opposite sides of the cell?
Spindle fibres
How many cells result from meiosis?
What kind of cells result from meiosis?
4
Haploid cells
Spermatogenesis begins with which cell?
Spermatogonia
By what mechanism to spermatogonia divide?
Mitosis
What to spermatogonia become?
Primary spermatocytes
What do primary spermatocytes become?
Secondary spermatocytes
What do secondary spermatocytes become?
Spermatids
What do spermatids become?
Spermatozoa
What is spermiogenesis?
The maturation of spermatids into spermatozoa
What does the acrosome of a spermatozoa contain?
What is the function of this?
Digestive enzymes
Break down the zona pellucida
How many days does spermatogenesis take?
70 days
Oogenesis begins with which cell?
Oogonia
What do oognia become?
Primary oocytes
What 2 things does a primary oocyte become?
Secondary oocyte
First polar body
How often is GnRH released?
Pulsatile release, every 1-2 hours
What are the 2 gonadotrophins?
LH
FSH
Which cells produce testosterone?
Leydig cells
Where in the testes does spermatogenesis occur?
Seminiferous tubules
Besides oestrogen, which other hormone inhibits FSH production by negative feedback?
Inhibin
What is the function of LH in males?
Stimulates Leydig cells to secrete testosterone
