Reproduction: Gametes And Hormones Flashcards
(40 cards)
What are the two main functions of the testes?
- sperm production
- hormone production
Where does sperm production occur in the testes? What is it controlled by?
- occurs in seminiferous tubules
- controlled by Sertoli (nurse) cells
- spermatogenesis also occurs
Where does hormone production occur in the testes? What hormones are produced? What produces these hormones?
- hormones produced by Leunig cells in between tubules
- produces testosterone (steroid or androgen)
What molecule is the precursor to testosterone?
Cholesterol.
What is spermatogenesis?
- Mitosis produces spermatogonium
- then converted into primary spermatocyte via meiosis
- meiosis then produces secondary spermatocyte
- then spermatid
- then sperm is moved along lumen via muscle cells.
What is the function of the acrosomal vesicle in sperm?
- contains enzymes that will degrade part of egg so sperm can fuse with egg (ensures close contact with DNA)
Do sperm have mitochondrion?
Yes
What does the axial filament of the sperm contain? Where is it located?
Contains 9+2 array of microtubules seen in cilia and flagella
What enables movement of sperm?
Beating flagella
What is testosterone produced by and where? What does testosterone act via?
- made by Leydig cells in between tubules
- acts via androgen receptor in cells
What can testosterone be converted into and why?
Can be converted into olestra diol by Sertoli cells to aid spermatogenesis
Describe the relationship between testosterone and accessory sex organs.
Testosterone stimulates accessory sex organs (prostate and seminal vesicles)
What does testosterone modulate? Describe an animal example.
Modulates secondary sex characteristics and male type behaviour e.g courtship and aggression.
E.g peacock has high level of testosterone during courtship behaviour (shows feathers).
Explain the process of controlling testis function (hypothalamo-pituitary-gonadal HPG axis).
- Gonadotropin releasing hormone (GnRH) from hypothalamus stimulates release of LH and FSH (the Gonadotropins) from the pituitary gland
- LH enters testis where it stimulates Leydig cells to produce testosterone
- Testosterone either binds to Sertoli cells or enters reproductive tract/accessory sex organs
- FSH enters testis where it stimulates Sertoli cells to undergo spermatogenesis and produces Inhibin
- testosterone from Leydig cells inhibits GNRH and LH production
- inhibin from Sertoli cells inhibits FSH production
How many eggs are females born with? Does this change?
Born with 2 million eggs. Decreases as time passes.
What is the surface of an ovary made of?
Tough epithelium
What occurs in the cortex of the ovary? What does the cortex contain?
Growth occurs in the cortex. It contains:
- germ cells
- follicles
- corpora lutea
- corpora albicans
What is the fastest growing tissue in the body of females?
Corpora lutea on ovary
What is the function of the medulla in the ovary? What does it contain?
Function is to supply blood in the ovary. Contains fibrous connective tissue, blood vessels, and nerves
Does the number of follicles in the ovary cortex change?
Fixed number set at birth
What is folliculogenesis?
Development of the follicle and the egg (oocyte)
What is the oocyte?
The egg cell that develops into ovum and then an embryo.
What is the function of Theca cells in the ovary? What would they be equivalent to in males?
Make androgens from cholesterol . Equivalent to Leydig cells
What is the function of Granulosa cells in the ovary?what would they be equivalent to in males?
Makes oestradiol from androgen. Equivalent to Sertoli cells
