Reproduction - QUIZ Flashcards
What is the role of LH and FSH in the process of spermatogenesis?
FSH: acts directly on the Sertoli cells to stimulate germ cell number
LH: acts on leydig cells to stimulate production of Testosterone
What is the role of LH and FSH in the process of oogenesis?
FSH: stimulates the growth of ovarian follicles in the ovary.
LH: helps control the menstrual cycle, surge triggers the release of an egg from the ovary.
Stimulate release of estrogen/ progesterone
What is the role of testosterone in the process of spermatogenesis and in the development of male sex characteristics?
- Stimulates spermatogenesis
- Stimulates development of male genitalia in fetus
- Stimulates changes in development of adult male during puberty
What are the roles of estrogen and progesterone in the menstrual cycle/ oogenesis, in the development of female sex characteristics?
- Progesterone causes thickening / repair of uterus lining / endometrium
- Estrogen (high lvls) stimulates LH secretion (ovulation)
- Cause development of female genitalia in the fetus & secondary sex characteristics
Know the roles of estrogen and progesterone during pregnancy and parturition (birth).
- Progesterone maintains uterus lining during pregnancy, develops breast tissue, stops contractions
- Estrogen triggers formation of fetal organs, regulates other hormones
- Less p & more e leads to labor/contractions
Compare and contrast the processes of spermatogenesis and oogenesis.
BOTH:
- result in haploid gametes
- involve two divisions of meiosis
- stimulated by hormones
- involve differentiation
O: in ovaries S: in testes
O: starts during fetal development
S: Starts during puberty
O: one cell S: four sperm (meiosis)
Outline the genetic and hormonal control of the development of male and female sexual characteristics (prenatal).
Male:
- XY chromosomes (Y develops testes)
- Testes secrete testosterone (stimulates spermatogenesis)
/ sexual characteristics)
Female:
- XX chromosomes (can have both dominant / recessive alleles - hemophilia)
- Estrogen & progesterone cause development of genitals / secondary sex characteristics
Identify the hormones involved in the menstrual cycle and know the origin of each.
- FSH and LH produced by pituitary gland
- Estrogen / progesterone produced by ovaries
Explain the process of spermatogenesis.
- Occurs in seminiferous tubule
- Two divisions of meiosis:
- Primary spermatocyte carries out first division
- Secondary carries out second division
- Meiosis produces haploid cells which differentiate into sperm cells
- Sertoli cells help sperm to differentiate
Explain the process of oogenesis.
- Oogenesis is the production of female gametes in the ovaries
- Primary oocytes begin meiosis, arrested in prophase I to form follicles (until menstrual cycle)
- Hormones (FSH / LH) trigger continued division of some primary oocytes
- One cell forms secondary oocyte, while other cell forms a polar body (cytoplasm divided unequally)
- 2nd oocyte begins the second meiotic division, arrested in metaphase II
- Secondary oocyte released from the ovary (ovulation) & enters fallopian tube
- If oocyte is fertilized chemical changes trigger completion of meiosis II (& formation of another polar body)
- Once meiosis II is complete the mature egg (ovum) fuses nuclei with sperm nucleus (zygote)
What are the roles and concentrations of oxytocin, estriol (a type of estrogen), and prostaglandins in the positive feedback mechanisms of birth?
- Estriol rises when stretch receptors detect child is too big
- Estriol causes less progesterone / uterus to be more sensitive to oxytocin
- Oxytocin causes uterine contractions
- Less progesterone = more oxytocin
- More contractions = more oxytocin (positive feedback)
- Fetus responds w prostaglandins which cause more contractions
What are roles (and concentrations) of progesterone, prolactin, and oxytocin in the processes of breast development, milk production, and lactation?
Progesterone: increases number of mammary glands
Prolactin: milk production / development of mammary glands
Oxytocin: causes muscles around the mammary glands to contract
Where does fertilization take place?
In the fallopian tubes (oviduct).
Explain the process of fertilization (including the acrosome reaction), and including the mechanisms that prevent polyspermy (the cortical reaction).
- Sperm enters fallopian tube & attaches to receptors in egg
- Acrosome reaction; release of hydrolytic enzymes from acrosome (softens jelly coating)
- Penetration of jelly coating, membranes of sperm and egg fuse
- Cortical reaction; granules released to destroy binding sites outside of egg (prevents polyspermy)
- Nucleus of 2nd oocyte completes meiosis II
- Fusion of neucei, diploid zygote forms
What occurs after fertilization?
- Cells inside undergo rapid mitotic divisions to form a blastocyst that implants in the uterine lining
