Term
| why are mitochondria necessary for sexual reproduction? |
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Definition
| only mitochondria contain the enzyme which converts cholesterol to pregnenolone - the precursor to all of the sex hormones. |
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Term
| why do you always inherit your mitochondria from your mother? |
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Definition
| b/c sperm have no mitochondria |
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Term
| do mitochondria have their own DNA? |
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Definition
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Term
| how is the adrenal gland like a donut? |
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Definition
| 90% of adrenal is cortex and in center 10% is medulla |
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Term
| what is the medulla of the adrenal gland composed of? |
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Definition
| chromaffin cells - which produce catecholamines. (a tumor here is called a pheochromocytoma - produces catecholamines in excess) |
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Term
| what is the adrenal cortex composed of? |
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Definition
| zona glomerulosa (aldosterone), zona fasciculata (glucocorticoids), zona and reticularis (androgens) |
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Term
| why is androgen (male hormone) production so necessary? |
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Definition
| b/c you need that to make estrogen (this is the ONLY way) |
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Term
| where are androgens produced? |
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Definition
| the adrenal cortex and gonads |
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Term
| how many androgens are there? what are they? (*possible exam question*) |
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Definition
| 5: DHEA (dehydroepiandrosterone), DHEA sulfate (only made in adrenal gland), androstenedione, testosterone and dihydrotestosterone |
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Term
| which 2 of the 5 androgens are the only ones w/receptors? what is the theory as to why this is? |
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Definition
| testosterone and dihydrotestosterone - so that the other androgens as they go through the pathways do not have uncontrolled effects. |
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Term
| regardless of the pathway, what is the form that all steroids have to go through along their synthetic pathway? |
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Definition
| *androstenedione - which can become testosterone or estrogen. |
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Term
| what can testosterone convert to? |
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Definition
| testosterone can go into a cell and convert to dihydrotestosterone (100% more potent than testosterone) or convert to estradiol (the major female estrogen) |
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Term
| why do most OCPs have ethanol estradiol? |
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Definition
| ethanol increases estradiol's strength 100x |
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Term
| is pregnenolone a hormone? |
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Definition
| no, b/c it has no function beyond being converted - automatically converts to progesterone or 17-hydroxypregnenolone, has no staying capacity. |
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Term
| what are uses for progesterone and 17-hydroxypregnenolone (products of pregnenolone conversion)? |
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Definition
| *17-hydroxypregnenolone: intermediate. *progesterone: not an androgen, but a precursor for aldosterone, cortisol and adrenal |
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Term
| what will a cortisol-producing tumor cause? |
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Definition
|
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Term
| what precursor does cortisol come from? |
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Definition
|
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Term
| how can high levels of cortisol lead to hypothyroidism? |
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Definition
| cortisol inhibits conversion of T4 to T3. T3 is the main integrator which controls release of substances. |
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Term
| what is "reverse T3"? when is it formed? |
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Definition
| reverse T3 attaches at T3's receptor, but has no function (makes the thyroid inert). reverse T3 is formed under stress. |
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Term
| what characterizes the onset of menopause? |
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Definition
| ovarian function progressively declines through the 40s and the resultant estrogen deficiency can cause: hot flashes, sweating, trouble sleeping (insomnia), and irritability. the build up of male hormone (as a result of no longer being converted to estrogen) also causes hair thinning, male pattern baldness and abnormal hair growth. |
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Term
| since women did not originally live to menopause, what is the biologic compensation for the build-up of testosterone? |
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Definition
| increased fat (slow down metabolism), which can convert testosterone to estradiol since the ovaries are no longer able to perform this function, and some of the symptoms of menopause are negated. modern HRT can also perform this more efficiently. |
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Term
| what is the relationship between estrogen and breast CA? |
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Definition
| estrogen can stimulate undetected breast CA (*does not cause it) |
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Term
| how does estrogen HRT affect the liver in a positive and negative way? |
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Definition
| estrogen triggers production of beta-globulins. some of these globulins bind to male hormone and inhibit its activity (positive) but others are involved in clotting and can cause DVTs (negative) |
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Term
| if a menopausal woman decides against HRT, what does she risk? |
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Definition
| becoming generally heavy, hairy, hypertensive and depressed |
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Term
| what are the key cells to the menstrual cycle? why? what stimulates this? |
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Definition
| the *granulosa cells are key to the menstrual cycle b/c they *convert male hormone to estrogen upon stimulation by FSH (works on granulosa cells to produce aromatase, the hormone converting enzyme). |
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Term
| where does male hormone come from in the ovary? what stimulates this? |
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Definition
| the theca cells, which surround the granulosa are stimulated to produce male hormone by LH. |
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Term
| what is the function of inhibins in the menstrual cycle? |
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Definition
| inhibins decrease FSH levels (FSH initially used to recruit, then support eggs) which kills off all the recruited eggs, except one - which becomes "egg of the month". |
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Term
| what is the effect of FSH and estrogen combined? |
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Definition
| *FSH and estrogen combined* produce *receptors for progesterone, which is necessary to produce before ovulation (2nd half of cycle) can begin (reason for slight spike in progesterone before ovulation, and deluge after). |
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Term
| how do different levels affect the function of estrogen? |
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Definition
| low level: inhibitory. high level: stimulatory for LH surge, which kicks off ovulation (first gen estrogen: stopped estrogen peak from occurring). |
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Term
| what function does progesterone perform in the 2nd half of the cycle? |
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Definition
| stimulation of a lush lining for the fertilized egg |
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