Thyroid + ETC Flashcards

1
Q

State which hormones correspond to hypothalamic-pituitary-thyroid axis

A

TRH (hypothalamus)
TSH (anterior pituitary)
T4/T3 (thyroid)

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2
Q

What is initial test to look for hyperthyroid or hypothyroid?

A

TSH

*need to interpret in context

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3
Q

How are T3 and T4 transported through blood? Why?

A

bound to TBG since they are hydrophobic

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4
Q

TSH effects

A

activates G-protein coupled receptor on follicular cell membranes

Gs makes cAMP which activates thyroid hormone synthesis

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5
Q

Thyroid hormone receptors

A

located on nuclear receptors on the nucleus

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6
Q

What increases BMR? What increases sympathetic nervous system? (both increased by thyroid hormone)

A

more Na/K+ ATPase (BMR)

more B1-adrenergic receptors

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7
Q

Colloid

A

a stored form of iodinzed thyroglobin

stored in the follicles

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8
Q

How does colloid get transported for use?

A

needs to be endocytosed back into the follicular endothilieal cell

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9
Q

Hypothyroidism lab values

A

high TSH w/ low free T4

*TSH is signaling for more thyroid hormone, but it is not working

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10
Q

Hyperthyroidism lab values

A

despite low TSH, free T4 remains high

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11
Q

Hypopituitary lab values

A

low TSH and low T4

*pituitary gland is not appropriately responding to thyroid hormone conditions

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12
Q

Pregnancy lab values

A

low TSH and high T4

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13
Q

Critical illness / starvation lab values

A

low TSH with mildly abnormal T4

*function returns to normal after illness is over

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14
Q

Carboxyhemoglobin

A

when CO binds heme instead of O2

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15
Q

Cytochrome C

A

also known as complex IV

has both Fe3+ and Fe 2+

when Fe3+ is reduced to Fe 2+, it then donates some protons to O2 to form H2O

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16
Q

Where does anaerobic fermentation always occur?

A

RBCs since they have no mitochondria

17
Q

Typical path of aerobic energy production (broad strokes)

A

glucose goes through glycolysis to form pyruvate

pyruvate becomes NADH and FADH2

goes through ETC to make ATP

18
Q

Typical path of anaerobic energy production

A

glucose goes through glycolysis to form pyruvate

pyruvate cannot go to ETC

Pyruvate is reduced to lactate instead

19
Q

When pyruvate is reduced, what gets oxidized?

A

both lactate and NADH

20
Q

ATP synthase

A

highly conserved complex to harvest chemoelectric potential of protons

protons go from intermembrane space to mitochondrial matrix

21
Q

What can inhibit ATP synthase?

A

oligomycin

22
Q

Where does CO bind?

A

to Fe2+ in both Hbg and ETC

has great affinity for heme

blocks ETC which causes more lactate fermentation

23
Q

Brown adipose tissue

A

uncoupling agent of ETC

uncouples movement of protons from ATP synthase (now everything goes to heat)

24
Q

What causes weight loss ?

A

conversion of calories into heat

25
How does thyroid hormone activate brown adipose?
increases mitogenesis increases UCP1
26
UCP1
uncoupling protein 1 that works with brown adipose tissue
27
What subunit rotates in ATP synthase?
the F1 subunit
28
When does prolactin increase?
prolactin is produced with TSH therefore, in hypothyroidism when TSH increases, so does prolactin
29
Why does glucose increase with hyperthyroidism?
need more blood glucose to fuel the excess energy production associated with hyperthyroidism