Chapter 4 - Reproduction and Development Flashcards
What reproductive hormone is released from the hypothalamus to the anterior pituitary?
gonadotropin releasing hormone (GnRH)
What gonadotropin hormones are released from the anterior pituitary to the gonads?
- luteinizing hormone (LH)
- follicle stimulating hormone (FSH)
What are the male and female gonads?
testes and ovaries
What are the two responses of the gonads to gonadotropins?
- production of steroid hormones
- production of germ cells
What are the germ cells in males and females?
spermatazoa and ova
Define spermatogenesis
production of sperm
What are the spermatogenic cells called that are closest to the basement membrane of the seminiferous tubule and how many chromosomes do they have?
spermatogonia - 46 chromosomes
What is the product of the mitotic division of the first spermatogenic cells and how many chromosomes do they have?
two primary spermatocytes - 46 chromosomes each
What is the product of the first meiotic division of spermatogenic cells and how many chromosomes do they have?
2 secondary spermatocytes - 23 chromosomes each
What is the product of the second meiotic division of spermatogenic cells and how many chromosomes do they have?
two spermatids - 23 chromosomes each
Each primary spermatocytes produces how many spermatids?
4
What is spermatogenic transmortion?
spermatids bud out to form spermatozoa
What structure of the spermatozoa helps them digest the lining of the egg?
acrosome
What is the function of Leydig cells?
They convert cholesterol to testosterone
What does testosterone do in Sertoli cells?
It binds a receptor, converting into dihydrotestosterone, which diffuses into the nucleus and instructs DNA to synthesize RNA.
What does LH do in the testes?
It binds to Leydig cell receptors resulting in a second messenger that increasing the conversion of cholesterol to testosterone.
What does FSH do in the testes?
It binds to Sertoli cell receptors, resulting in a secondary response that converts testosterone to hydrotestosterone.
What feedback mechanism results if testosterone is too high?
It inhibits the hypothalamus’ release of GnRH and anterior pituitary’s release of LH.
What feedback mechanism results when dihydrotestosterone is too high?
It inhibits the anterior pituitary’s release of FSH.
What hormone is responsible for secondary sex characteristics in the male?
testosterone
Where is sperm stored?
in the epididymis and vas deferens
Define oogenesis
production of ova
In oogenesis, what occurs during the 2-3 months of female fetal development?
Oogonia undergo mitotic division to produce primary oocytes.