Chapter 26 - Reproduction and development Flashcards
What are the gonads, internal genitalia, and external genitalia?
The gonads (ovaries, testes) produces gametes, so sperm and eggs The internal genitalia consist of glands and ducts connecting the gonads to the external environment The external genitalia are all external reproductive structures
IN the absence of a Y chromosome, an embryo will develop into a ……….
female
What are Sertoli cells? Their function? What do they secrete?
Sertoli cells are elongated cells in the seminiferous tubules. The nourish spermatocytes. They secrete anti-mullerian hormone causing the regression of the mullerian ducts
What are Leydig cells? Their function? What do they secrete?
Leydig cells are clusters of epitheliod cells in the testis. They are endocrine cells secreting androgens, testosterone and DHT
What is the function of DHT( dihydroxytestosterone)?
It promotes development of the prostate gland and the external genitalia
Describe female embryonic development; in the absence of ………., the mullerian ducts develop into the vagina, uterus, and fallopian tubes. The wollfian ducts ……….. without testosterone
testosterone, regress
What do the Wolffian ducts form? Under influence of which hormone are the wolffian ducts?
The epididymis and vas deferens, testosterone
What do the mullerian ducts develop into? Under influence of which hormone?
They become the fallopian tubes, uterus, cervix, and upper vagina. Under the influence of AMH(anti-mullerian hormone)
Testicular development doesn’t/does require testosterone?
Doesn’t
What are the 4 general steps of gametogenesis?
- Spermatogonia and oogonia undergo mitosis to increase their numbers
- the germ cells DNA replicates until each chromosome is duplicated, forming primary spermatocytes and oocytes
- one primary gamete divides into two secondary gametes, making secondary spermatocytes or oocytes (in females one secondary oocyte, the first polar body) (in males two identical secondary spermatocyte)
- The second meiotic division seperates the sister chromatids
What are the 5 steps of male gametogenesis, starting at the birth?
- At birth, sperm are not past mitosis
- At puberty, spermatogonia have two fates, some keep performing mitosis, others become primary spermatocytes
- primary spermatocytes divide into two secondary spermatocytes
- each secondary spermatocyte divides into two spermatids
- spermatids mature into sperm
What are the 5 steps of female gametogenesis?
- oogonia complete mitosis resulting in primary oocytes
- In puberty, a primary oocyte develops into a secondary oocyte and the first polar body. The first polar body disintegrates
- if the secondary oocyte is selected for ovulation, the second meiotic division takes place just before the egg is released from the ovary
- if the egg is not fertilized, meiosis never completes
- if fertilization takes place, the secondary oocyte is split into the fertilized egg and the second polar boyd
what are the three main steroid sex hormones?
estrogen, progesterone, and androgens (testosterone, DHT)
What is the function of aromatase with regards to hormones?
Aromatase converts androgens to estrogens
What does FSH do?
FSH regulates gametogenesis in the gonads
What does LH do?
LH stimulates production of steriod sex hormones