Thyroid + ETC

Question 1

State which hormones correspond to hypothalamic-pituitary-thyroid axis

Answer 1

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

Question 2

What is initial test to look for hyperthyroid or hypothyroid?

Answer 2

TSH

*need to interpret in context

Question 3

How are T3 and T4 transported through blood? Why?

Answer 3

bound to TBG since they are hydrophobic

Question 4

TSH effects

Answer 4

activates G-protein coupled receptor on follicular cell membranes

Gs makes cAMP which activates thyroid hormone synthesis

Question 5

Thyroid hormone receptors

Answer 5

located on nuclear receptors on the nucleus

Question 6

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

Answer 6

more Na/K+ ATPase (BMR)

more B1-adrenergic receptors

Question 7

Colloid

Answer 7

a stored form of iodinzed thyroglobin

stored in the follicles

Question 8

How does colloid get transported for use?

Answer 8

needs to be endocytosed back into the follicular endothilieal cell

Question 9

Hypothyroidism lab values

Answer 9

high TSH w/ low free T4

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

Question 10

Hyperthyroidism lab values

Answer 10

despite low TSH, free T4 remains high

Question 11

Hypopituitary lab values

Answer 11

low TSH and low T4

*pituitary gland is not appropriately responding to thyroid hormone conditions

Question 12

Pregnancy lab values

Answer 12

low TSH and high T4

Question 13

Critical illness / starvation lab values

Answer 13

low TSH with mildly abnormal T4

*function returns to normal after illness is over

Question 14

Carboxyhemoglobin

Answer 14

when CO binds heme instead of O2

Question 15

Cytochrome C

Answer 15

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

Question 16

Where does anaerobic fermentation always occur?

Answer 16

RBCs since they have no mitochondria

Question 17

Typical path of aerobic energy production (broad strokes)

Answer 17

glucose goes through glycolysis to form pyruvate

pyruvate becomes NADH and FADH2

goes through ETC to make ATP

Question 18

Typical path of anaerobic energy production

Answer 18

glucose goes through glycolysis to form pyruvate

pyruvate cannot go to ETC

Pyruvate is reduced to lactate instead

Question 19

When pyruvate is reduced, what gets oxidized?

Answer 19

both lactate and NADH

Question 20

ATP synthase

Answer 20

highly conserved complex to harvest chemoelectric potential of protons

protons go from intermembrane space to mitochondrial matrix

Question 21

What can inhibit ATP synthase?

Answer 21

oligomycin

Question 22

Where does CO bind?

Answer 22

to Fe2+ in both Hbg and ETC

has great affinity for heme

blocks ETC which causes more lactate fermentation

Question 23

Brown adipose tissue

Answer 23

uncoupling agent of ETC

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

Question 24

What causes weight loss ?

Answer 24

conversion of calories into heat

Question 25

How does thyroid hormone activate brown adipose?

Answer 25

increases mitogenesis

increases UCP1

Question 26

UCP1

Answer 26

uncoupling protein 1 that works with brown adipose tissue

Question 27

What subunit rotates in ATP synthase?

Answer 27

the F1 subunit

Question 28

When does prolactin increase?

Answer 28

prolactin is produced with TSH

therefore, in hypothyroidism when TSH increases, so does prolactin

Question 29

Why does glucose increase with hyperthyroidism?

Answer 29

need more blood glucose to fuel the excess energy production associated with hyperthyroidism