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22 Cards in this Set
- Front
- Back
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Gonads |
Produce gametes -> provides sex hormones Testis: testosterone Ovaries: oestrogen |
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Function of reproductive tract |
Passage and supportive secretions for gametes Consists of ducts and glands Maintenance of species Endocrine and paracrine function -> maintain the life of the individual |
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Primordial germ cells |
Produce gametes, carry genetic info Male: spermatozoa Female: oocytes |
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Mesenchymal cells |
Female: theca and granulosa cells Male: sertoli and leydig cells |
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Granulosa and sertoli cells |
Nursing and fostering the germ cell during its maturation and movement to the genital duct system |
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Leydig and thecal cells |
Production of androgenic hormones |
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Genetic basis of sexual differentiation |
46 chromosomes: 22 paired autosomes, 1 pair of sex chromosome (diploid) Meiotic division: formation of oocytes and spermatozoa (23 chromosomes) (haploid) After fertilisation -> -> offspring (46 chromosomes) Embryo develop by meiotic cell division, each contains 46 chromosomes |
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Development of male gonads |
Wk 3-7: Wolffian and Mullerian genital duct developed either side of the gonads, embryo is sexually indeterminate Wek 7: Anti mullerian hormone from sertoli cells -> atrophy of mullerian duct -> decent of testis FSH terminates the production of AMH Wk 9: Testosterone stimulated Wolffian duct to differentiate to epididymis, vas deferens, seminal vesicles, ejaculatory duct => positive feedback from gonads is required to produce a masculine format |
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Development of female gonads |
Wk 3-7: Wolfian and Mullerian duct dev on either side of gonads, embryo is sexually indeterminate Wk 9: Absence of testosterone -> regression of Wolffian duct Absence of AMH -> differentiation of Mullerian duct into fallopian tubes, ovaries, vagina, uterus, cervix Wk 18-20: completed Development of female genitalia does not require gonad hormones
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Sexual differentiation does not depend on? |
fetal pituitary gonadotrophins |
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What determines the pattern of gonadotrophins secretions? |
Testosterone Female: cyclical Male: constant
Once female pattern established, testosterone cannot influence the organs |
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Formation of male external organ |
fetal testosterone is converted to Dihydro-testosterone by intracellular 5 alpha reductase. Dihydrotestosterone is responsible for development of penile urethra, prostate glands, scrotum, glans penis |
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Formation of female internal organ |
No any overt hormone influence required for lowered vagina, clitoris, labia majora and minora After differentiation, expose to androgen leads to the enlargement of clitoris |
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What regulates sex steroid hormones ? |
Anterior Pituitary Gland: LH and FSH |
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FH and FSH structure |
FSH is heavier than LH Both have alpha subunit but different beta subunit, physiological activity resides on beta subunits But can not work without alpha or beta subunit Ph
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Steroidogenesis |
Gonadotropins produced via plasma membrane receptors (Unlike steroid hormones) -> changes in cAMP -> activates PKC
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LH receptors |
Increase uptake of HDL and LDL Activates 20, 22 demolase enzymes (CYP11A1) Convert cholesterone -> pregnanolone -> androsterone
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LH |
activates granulosa cells -> produce progesterone |
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FSH |
activates granulosa and leydig cells aromatase enzymes to convert androsterone -> testosterone ->estradiol |
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Activation of FSH receptors |
Increase number of LH receptors expression -> increase sensitivity to LH -Supply androsterone from interstitial cells for oestrogen formation (paracrine) -Production of progesterone from granulosa cell |
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What regulates the anterior pituitary gonadotropins? |
Hypothalamus: neurones terminate on the portal vessels of the median eminence -> secretes GnRH Oestradiol and testosterone: exert negative feedback control |
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Oestrogen |
Work by a genomic/ nuclear activation response Slow in process by promoting interaction between the CoA and oestrogen response element -> stimulate transcription via conformational changes and dimerization
Agents deemed to be antagonist/modulators (clomiphen ) promote interaction between CoR and ER to alter the protein transcription |
