Repro Flashcards
What are the 3 main classes of hormones?
- Steroids nucleus
- proteins/peptides (glycoproteins) membrane
- eicosanoids
What are the diff ways of hormone delivery?
- Endocrine (EX: estradiol, FSH)
- Neuroendocrine (EX: GnRH)
- Paracrine (EX: testosterone from leydig to sertoli)
- Autocrine (EX: estradiol)
- Pheromonal/ectohormonal (EX: Bruce effect/ram effect)
Describe supraphysiological stimulation.
-internalization of hormone receptors
-hormone is ineffective
EX: prolonged release, high GnRH
>contraceptive in dogs, horses
>suprarelin
Describe the source of production of hormones.
- Pineal = melatonin
- Hypothalamus = GnRH
- Pituitary = FSH, LH, prolactin, oxytocin
- Ovary = estradiol, progesterone, inhibin, testosterone, relaxin, oxytocin
- Testis = testosterone, inhibin, estradiol
- Uterus = prostaglandin F2 a
- Placenta = progesterone, estradiol, hCG, eCG, oxytocin, PGF2a
Describe the hormones biochemical structure.
- Peptide (proteins) = sm. Few amino acids. Easily broken [oxytocin, GnRH, prolactin]
- Glycoproteins = carbohydrate & protein. Easily broken [FSH, LH, eCG]
- Steroids = cholesterol. Transpass cell membranes. [estradiol, progesterone, testosterone]
- Prostaglandins = eicosanoid lipid [PGF2a, PGE2]
Describe estradiol.
-made by follicular cells in ovary
-fetoplacental unit
-synthesized from androgens by aromatase
-metabolized in liver
FUNCTION:
F = sexual behavior, LH surge, uterine prep, vag proliferation, role in preg, bone health, immune response
M = testicular health
Describe progesterone.
-made by ovary (CL) after ovulation
>prolif & diff of granulosa cells (lg luteal) & theca interna (sm luteal)
-metabolized in liver
FUNCTIONS:
F = maintain preg, sex behavior, mammary gland develop, immune, brain
Describe testosterone (androgen).
-made by leydig
-metabolized in liver
FUNCTION:
Masculinization, repro tract develop, spermatogenesis, male sex behavior, anabolic, erythropoietic
Describe GnRH.
-made by hypothalamus
-regulated by estrogens
-downregulation
FUNCTION:
F & M = regulate gonadotropins, LH, & FSH
Describe LH.
-made by anterior pituitary (adenohypophysis)
-downregulation
FUNCTION:
F = follicular maturation & ovulation
M = spermatogenesis
Describe FSH.
-made by anterior pituitary
-downregulation
FUNCTION:
F = follicular development
M = act on sertoli FSH to form secondary spermatocytes
Describe prostaglandins.
-PGF2a & PGE2
FUNCTION:
PGF2a = luteolysis of CL & uterine contraction
PGE2 = material recognition of preg in mares
Describe oxytocin.
-made by hypothalamus but released by posterior pituitary (neurohypophysis) & CL
-downregulation
FUNCTION:
uterine contraction, milk ejection, maternal recognition of preg, luteolytic release of prostaglandins
Describe melatonin.
-made by pineal gland
FUNCTION:
Seasonality, regulates GnRH
Describe eCG or PMSG.
-made by endometrial cups
-superovulation
FUNCTION:
Follicles, develop of CL, eCG is FSH & LH-like
Describe inhibin.
-made by granulosa & sertoli (dominant follicle)
-neg feedback to anterior
-gonadal glycoproteins
-follicular deviation
FUNCTION:
Regulate FSH release from pituitary gland
Describe AMH.
-F = made by granulosa cells of preantral & sm antral follicles
-M = activated by sertoli during fetal develop
FUNCTION:
F = regulate folliculogenesis
M = SOX9 inhibits development of female repro (Müllerian duct)
Describe the hypothalamic pituitary gonadal axis.
Describe the hypothalamo-pituitary portal system.
-microcirculation connecting the hypothalamus with the anterior pituitary
-GnRH, GHRH, CRH, TRH
-hypothalamic center in females & surge
>tonic = low amp GnRH pulses
>surge = high level of estradiol & high amp GnRH pulse
-regulate levels of estrogens
FUNCTION:
Transport & exchange hormones between the hypothalamus arcuate nucleus & anterior pituitary gland
Describe prenatal development.
Sequential
-embryology
-sex diff
-fetal maturation
Describe the signaling pathways for embryo development.
-specify cell fate via transcription & development
>contact
>paracrine
>endocrine
>synaptic
Describe totipotent.
Cells that give rise to embryo.
Describe endoderm, mesoderm, and ectoderm.
Ectoderm=
-repro tract
-cd vag & vestibule
-mammary gland
-penis & clit
-pituitary gland
-hypothalamus
-oral & nasal cavity
-sweat gland
Mesoderm=
-gonads
-uterus, cervix, cr vag
-epididymis, ductus deferens
-accessory sex glands
-urinary system
Endoderm=
-glands
What does the trophoblast make?
Placenta
Describe embryo VS fetus.
Embryo = no anatomical form that can be recognized
Fetus = recognizable species marked by placentation development
Describe the reproductive events (trimester).
1st trimester = sex diff (chromosome)
2nd trimester = develop repro tract
3rd trimester = testicular descent
Describe sex differentiation (3).
- Genetic (chromosomal) sex
-determined at fertilization
*karyotypes:
>XX or XY in mammals
>ZZ (M) or ZW (F) in birds - Gonadal sex
-testis determining gene = SRY & SOX9
-ovary determining genes = RSPO1 & WNT - Phenotypic sex
-tubular & external structures
-AMH, testosterone, DHT
Describe present SRY gene & absent SRY gene.
- Presence of SRY = testis determine factor (TDF)
-in sex cord of male
-medullary sex cord -> sertoli
-cortical sex cord -> degen
-sex cord -> seminiferous tubules & rete testis
-pre sertoli = make AMH - Absence of SRY
-cortical sex cords -> follicles
-medullary sex cords -> degen = female
Describe primordial germ cells.
Migrate from outside (yolk sac) into organism through hind gut to undifferentiated gonad at genital ridge.
Describe mesonephric duct VS paramesonephric duct.
Mesonephric = wolffian (male) duct
>Epididymis/ductus deferens
Paramesonephric = mullerian (female) duct default
>oviduct/uterus/cervix/cranial vag
reproductive system develops at the same time as renal system
[cloaca = rectum]
What does the physical sex organ characteristics rely on the presence of?
-TDF & SRY
>development of testes & production of testosterone via leydig cells
-AMH
>degen paramesonephric duct
-DHT
>development of penis, scrotum, accessory sex glands
Describe freemartinism.
-bovine
-male (developed first) & female twins (F is infertile)
-fusion of placental circulation
-AMH transferred from M to F
-regress Müllerian ducts
-vestigial develop of vag, cervix, uterus, uterine tube
-normal vulva & vestibulum derived from urogenital sinus
Describe the hypothalamus in M VS F.
Female =
-2 areas to secrete GnRH
>tonic (M & F) - ARC
>surge (F only) - POA
-fetal ovaries make estradiol but can’t cross BBB bc its bound to aFP
Male =
-testosterone crosses BBB & converted to estradiol which defeminizes hypothalamus = eliminating surge
Describe fetal maturation in M & F.
Male = testicle descend into scrotum (temp control)
>gubernaculum enlarge
Female = broad lig & ovaries migrate caudal (except in mares)
