endocrine 3 Flashcards

1
Q

___ pituitary secretes 7 hormones, synthesis and release of each of the 7 is under control of…

A

anterior

1 of 7 releasing factors synthesized in hypothalamus

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2
Q

the ___ is where all the releasing factors from hypothalamus are released into

A

median eminence

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3
Q

the anterior lobe of pituitary contains ___ cells, so it is called ___

A

classical endocrine secretory cells (no neuro)

endohypophysis (pars distalis)

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4
Q

what is a unique feature of anterior pituitary structure with hypothalamus?

A

they are directly connected by set of modified blood vessels called the portal vessels/system –>special set of capillaries at bottom of hypothalamus that are the receiving point for all the receiving factors, they are dumped right into the capillaries –> the capillaries do not have the typical blood-brain barrier b/w CSF and blood, so very permeable, which allows releasing factors to diffuse right into blood –> capillary beds then form a portal vein, goes down hypothalamic hypophysial –> 2nd cap bed, releases all releasing factors

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5
Q

releasing factors can be synthesized and secreted in very…

A

small concentrations –> directly transported from hypothalamus to anterior pituitary where they have their effect –> then released into general circulatory system & diluted below their effective concentrations, effects are stopped

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6
Q

how are the circulations between anterior & posterior pituitary related?

A

completely separate - 2 separate capillary beds & circulations

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7
Q

hypothalamus produces 7 releasing factors & dumps into median eminence, what are their classifications?

A

6 peptides & 1 amine

4 stimulatory peptides
3 inhibitory (2 peptides & 1 amine)

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8
Q

what are the 2 major cell types in anterior pituitary?

A

acidophils - stain orange/red in response to dyes, acid-loving (secrete GH & prolactin)

basophils - stain blue with basic dyes, secrete ACTH, TSH, MSH, LH & FSH

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9
Q

how are glucocorticoids regulated? give example

A

by negative feedback short & long loops

endocrine gland A is hypothalamus, target tissue B is anterior pituitary –> endocrine gland A’s signal/hormone is 1 of the 7 releasing factors –> hits target tissue B(anterior pituitary) when then releases one of the 7 hormones –> downstream target of anterior pituitary is one of the 7 targets that the hormone effects

short loop: hormone from pituitary goes back to hypothalamus and shuts off releasing factor
long loop: hormone from other gland in body goes to hypothalamus and shuts off releasing factor

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10
Q

what is the precursor of glucocorticoids? and name a few

A

steroid hormones all derived from cholesterol

3 major glucocorticoids: cortisol, cortisone, corticosterone - helps regulate glucose metabolism in the body

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11
Q

what is the signal for production of glucocorticoids?

A

long-term stress or starvation (long-term depletion of carbohydrate stores)

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12
Q

describe the feedback loop and the RF & hormones involved in making glucocorticoids

A

glucose is primary metabolic fuel and is readily available from glycogen…when glycogen levels are depleted, have to call on alternate sources for glucose

signal of starvation/stress received by hypothalamus –> synthesizes & secretes releasing factor CRH –> CRH released to portal system and travels to anterior pituitary where it has stimulatory effect and causes synthesis & release of ACTH (tropic hormone- effects another gland) –> ACTH target tissue is adrenal cortex –> stimulatory, synthesis & secretion of glucocorticoids –> ACTH also feeds back to hypothalamus and cuts off production of CRH (short feedback loop) –> glucocorticoids have multiple target tissues, also circulate & feed back to hypothalamus to cut production of CRH (long feedback loop)

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13
Q

glucocorticoids are steroids so…

A

they dissolve thru target tissue membrane and bind to receptor in cytoplasm & form glucocorticoid-receptor complex –> migrates to nucleus and binds to glucocorticoid-receptor elements (GREs), can be positive and active a gene or can be negative and turn off gene

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14
Q

what is glucocorticoids major function in regulating glucose production?

A

they active enzymes that will synthesize glucose from non-carbohydrate sources

keep your body running thru other metabolic sources of fuel

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15
Q

what is the first non-carbohydrate source that glucocorticoids help produce?

A

lipids/fats – convert fats to glucose & ATP

glucocorticoids upregulate genes that result in production of enzymes, lipases –> lipases act on lipids, resulting in glycerol & phospholipids –> they run thru metabolic pathways to continue making ATP thru TCA cycle –> glycerol can be used to also make more glucose

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16
Q

what is the second non-carb source that glucocorticoids help produce?

A

amino acids

glucocorticoids bind genes and inhibit genes responsible for protein synthesis & activate genes responsible for protein breakdown –> break down proteins into amino acids –> AAs deaminated –> carbohydrate chain put into glycolysis and TCA to keep making ATP

17
Q

in extreme cases, ___ also get funneled thru the liver and muscle to make more ATP

A

ketone bodies

18
Q

glucocorticoids also act as ___ thru gene activation or suppression

A

anti-inflammatories

GREs activate anti-inflammatory genes and they turn off genes that make inflammatory compounds (cytokines, chemokines)