Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

D&T3 Exam 1 > Thyroid-valentovic > Flashcards

Thyroid-valentovic Flashcards

1
Q

Iodide uptake

A

Active transport of iodide into thyroid follicular epithelial cells occurs via the Na/I symporter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Iodide uptake

Inhibited by

A

Uncouplers of oxidative phosphorylation (lose ATP) production)

Thiocyanate and perchlorate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Iodide trapping stimulated by…

A

TSH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Iodide concentration and thyroid hormone secretion

A

Iodide concentration inversely modulates thyroid hormone secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Thyroid hormone release is inhibited by…

A

Lithium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which Thyroid hormone(s) is/are released into circulation

A

T3 and T4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How are T4 and T3 transported

A

Bound to thyroxine binding globulin (TBG)

T4 also by transthyretin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the predominant hormone in the blood?

A

T4!!!!!!

IMPORTANT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the most active thyroid hormone?

A

T3 (5x more active than T4)

IMPORTANT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

T3 peripheral formation

A

T4 deiodinated to T3 by iodothyronine 5-deiodinase (3 isoenzymes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Isozymes of iodothyronine 5-deiodinase

D1

Where is it expressed?

A

Liver, kidney, and thyroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Isozymes of iodothyronine 5-deiodinase

D1

What is its function?

A

Conversion of T4 to T3

Responsible for majority of circulating T3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Isozymes of iodothyronine 5-deiodinase

D1

What is it inhibited by?

A

Propylthiouracil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Isozymes of iodothyronine 5-deiodinase

D2

Where is it expressed?

A

Brain, pituitary, skeletal and cardiac mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Isozymes of iodothyronine 5-deiodinase

D2

Function

A

Influences intracellular T3 levels in these tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Isozymes of iodothyronine 5-deiodinase

D2

What is it inhibited by?

A

Unresponsive to propylthiouracil

17
Q

Where is 5-deiodinase activity highest?

A

Liver

18
Q

Thyroid hormone metabolism

A

Metabolized by P450

ENZYME INDUCERS WILL INCREASE CONVERSION OF T4 TO T3

19
Q

Primary hypothyroidism

Define

A

Diminished thyroid hormone production and high TSH levels

20
Q

Primary hypothyroidism

Causes

A

Hypothyroidism

Chronic autoimmune thyroiditis or Hashimoto’s thyroiditis (MC)

Thyroid damage due to rx with radioactive iodine

Surgical removal of thyroid

21
Q

Secondary hypothyroidism

Define

A

Pituitary hypothyroidism: due to TSH deficiency

22
Q

Thyroid hormone supplementation

What is DOC?

A

Levothroxine (T4)

23
Q

Thyroid hormone supplementation

Why is liothyronine (T3) not DOC?

A

Shorter half-life, greater variability

24
Q

Thyroid hormone supplementation

When can liothyronine (T3) be used?

A

Individuals with 5 deiodinase deficiency

25
Q

Levothyroxine T4

Used for

A

Hypothyroidism

Suppression TSH in cases of benign nodules or large mutinodular goiter

Hashimoto’s

Suppression of TSH thyroid carcinoma

26
Q

Levothyroxine T4

IV for…

A

Treating myxedema coma

Life threatening situation

Severe hypothyroidism

27
Q

Levothyroxine T4

Drug interactions

A

Ca carbonate

Aluminum hydroxide

Cholestyramine

Colesevelam

28
Q

Levothyroxine T4

Agents that alter TBG

A

Estrogen inc TBG

Clinical action: inc T4

Glucocorticoids, anabolic steroids dec TBG

29
Q

Levothyroxine T4

Agents that inhibit 5 deiodinase

A

Propylthiouracil

Amiodarone

30
Q

Levothyroxine T4

ADR

A

Cardiovascular

31
Q

Hyperthyroidism

MC cause

A

Graves’ disease: abs bind to TSH receptors=>inc T4 production (elevated T4, T3, but low TSH)

32
Q

Hyperthyroidism

Tx

A

Thionamides: propylthiouracil and methimazole

33
Q

Propylthiouracil and methimazole (antithyroids)

MOA

A

Inhibit iodide incorporation into tyrosine residues
Inhibit iodotyrosyl coupling to form iodothyronine

Propylthiouracil inhibits peripheral 5-deiodinase (D1) conversion of T4 to T3

34
Q

Propylthiouracil and methimazole (antithyroids)

Use

A

Hyperthyroidism

Propylthiouracil preferred drug in pregnancy

Methimazole: half life 6 hr (propylthiouracil: 1 hr)

35
Q

Propylthiouracil and methimazole (antithyroids)

ADR

A

Methimazole: agranulocytosis and aplastic anemia

Propylthiouracil: hepatic necrosis and nephritis

36
Q

Propylthiouracil and methimazole (antithyroids)

Block box warning

A

Propylthiouracil ass with liver injury and failure

D&T3 Exam 1 (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions