W8 - Reproductive Systems (lecture) Flashcards
What are the 2 reasons we need reproduction?
Propagation of life and genetic variability
What are the two main functions of the reproductive system?
Production of haploid gametes and production of hormones
What are the two main groups of reproductive hormones?
Steroid and gonadotropins
What are all steroid hormones derived from?
Cholesterol
Gonadotropins are protein based, give two examples of them in females
Luteinising hormone and follicle-stimulating hormone
Is oxytocin a steroid or gonadotropin?
Neither
What type of enzymes are CYP enzymes?
Hydroxylate enzymes
What type of enzyme are HSD enyzmes?
Hydroxysteroid dehydrogenase enzymes
What is required for a specific organ to produce it’s specific steroid hormone?
A complete set of enzymes needed to appropriately modified cholesterol
If there is a mutation causing a non-functional SRY gene, what may happen during fetal development of an XY individual?
No production of TDF and so female reproductive tracts form (therefore is XY with female phenotype)
Testosterone is both reproductive and non-reprod in terms of it’s actions, what are the reproductive functions? (3)
Secondary sexual characteristics, genitalia growth and maturation and spermatogenesis
What are the 3 non-reproductive actions of testosterone?
Libido and bone growth at puberty and protein anabolic effect
What receptor mostly mediates effects of testosterone?
Androgen receptor
Estradiol and progesterone also have both reprod and non-reprod effects, what are the 2 non-reprod actions?
Increase in adipogenesis and increase bone mineral density
Reprod actions of female gonadal steroid can include secondary sexual characteristics, reprod tract growth and maturation and the menstrual cycle, what 3 other things do they have roles in?
Oogenesis, breast growth/lactation suppression for pregnancy and parturition
XO leads to Turner syndrome and XXX is a trisomy of X, what happens if someone has XXY or XYY?
XXY - Klinefelter syndrome, XYY - Jacobs syndrome
It’s very unlikely but an SRY gene can appear on an X chromosome resulting in an XX SRY+ve male, how would this occur?
Via recombination
What are the 3 parts of the ovarian cycle?
Follicular phase, ovulation and luteal phase
What are the 3 parts of the uterine/menstrual cycle?
Menstruation, proliferative phase and secretory phase
How does the pill prevent ovulation + menstruation?
Increases progesterone always so the cycle is always kept in the secretory phase
During pre-puberty, all oocytes are arrested in prophase I and then only one egg cell per month moves into metaphase, why may this be an issue?
Long periods of time that these cells are kept in arrest affect the chance of infertility
What cells do FSH and LH act on in the male reproductive system?
FSH - sertoli cells, LH - interstitial cells
Interstitial cells produce testosterone, what does testosterone stimulate?
Mitotic and meiotic divisions that transform undifferentiated diploid spermatogonia into undifferentiated haploid spermatids
Testosterone has +ve and -ve feedback, +ve on gametogenesis, where does it affect -vely?
HT - producing GnRH and APG - producing FSH/LH
What is there high levels of in the 1st trimester?
Human chorionic gonadotropin (hCG)
Oxytocin is a peptide HM produced in the HT, where is it released?
Pituitary gland
Oxytocin has primary effects on muscle contraction, in what two ways may this be useful? (it can also effect muscle contraction in sexual intercourse)
For labour - contractions of the uterus and lactation - contraction of myoepithelial cells to release milk
OT’s secondary effects are as a neuromediator in recognition, trust and romantic attachment, what 2 other things is it a neuromediator for?
Parent-infant bonding and roles in addiction/depression
The Fergusson reflex is a positive reflex spiral, increased uterine contractions leads to neuroendocrine reflex, describe this
Increased oxytocin secretion has +ve feedback directly on contractions and indirectly by increasing production on prostaglandins which in turn increase contractions
