(MD 1) Human Physiology > Thyroid / > Flashcards

Thyroid / Flashcards

(78 cards)

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1
Q

IDENTIFY: Functional unit of the thyroid gland

A

Follicle

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2
Q

IDENTIFY: Substance inside follicles containing thyroglobulin

A

Colloid

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3
Q

IDENTIFY: Protein containing tyrosyl residues that form thyroid hormones

A

Thyroglobulin

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4
Q

IDENTIFY: Cells producing calcitonin

A

Parafollicular (C) cells

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5
Q

IDENTIFY: Hormone comprising 90% of thyroid secretion

A

T4

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6
Q

IDENTIFY: Active thyroid hormone

A

T3

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7
Q

IDENTIFY: Inactive hormone opposing thyroid hormone effects

A

rT3

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8
Q

IDENTIFY: Symporter responsible for iodide trapping

A

NIS

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9
Q

IDENTIFY: Enzyme that oxidizes iodide to iodine

A

TPO

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10
Q

IDENTIFY: Protein transporting iodide into colloid

A

Pendrin

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11
Q

IDENTIFY: Process of attaching iodine to tyrosine

A

Organification

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12
Q

IDENTIFY: MIT + DIT produces

A

T3

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13
Q

IDENTIFY: DIT + DIT produces

A

T4

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14
Q

IDENTIFY: Enzyme releasing T3/T4 from thyroglobulin

A

Lysosomal enzymes

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15
Q

IDENTIFY: Protein binding most thyroid hormones in plasma

A

TBG

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16
Q

IDENTIFY: Transport protein that crosses BBB to CNS

A

Transthyretin

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17
Q

IDENTIFY: Hormone stimulating thyroid gland

A

TSH

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18
Q

IDENTIFY: Hormone from hypothalamus controlling TSH

A

TRH

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19
Q

IDENTIFY: Effect of excess iodide suppressing TPO

A

Wolff-Chaikoff effect

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20
Q

IDENTIFY: Hormone causing exophthalmos disease

A

Graves disease

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21
Q

IDENTIFY: Swelling due to mucopolysaccharide accumulation in hypothyroidism

A

Myxedema

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22
Q

IDENTIFY: Enzyme converting T4 → T3 in tissues

A

Deiodinase

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23
Q

IDENTIFY: Deiodinase supplying circulating T3

A

D1

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24
Q

IDENTIFY: Deiodinase supplying intracellular T3

A

D2

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25
IDENTIFY: Deiodinase producing reverse T3
D3
26
TRUE OR FALSE: T4 has greater receptor affinity than T3.
False
27
TRUE OR FALSE: Only free thyroid hormone is biologically active.
True
28
TRUE OR FALSE: Protein binding shortens hormone half-life.
False
29
TRUE OR FALSE: Thyroid hormones directly stimulate sympathetic nerves.
False
30
TRUE OR FALSE: Thyroid hormones increase β-receptor expression.
True
31
TRUE OR FALSE: Increased thyroid hormone always increases serum glucose levels.
False
32
TRUE OR FALSE: Thyroid hormones stimulate both lipogenesis and lipolysis.
True
33
TRUE OR FALSE: Thyroid hormones increase thermogenesis via futile cycles.
True
34
TRUE OR FALSE: T3 feedback inhibition is rapid.
False
35
TRUE OR FALSE: Stored iodine can supply hormone production for months.
True
36
TRUE OR FALSE: TSH stimulates hypertrophy of follicular cells.
True
37
TRUE OR FALSE: Pendrin is involved in iodide oxidation.
False
38
TRUE OR FALSE: Lysosomes release thyroid hormone from thyroglobulin.
True
39
TRUE OR FALSE: D3 increases active thyroid hormone levels.
False
40
TRUE OR FALSE: Transthyretin transports T3 into brain.
False
41
TRUE OR FALSE: Hyperthyroidism increases BMR.
True
42
TRUE OR FALSE: Hyperthyroidism increases BMR.
True
43
TRUE OR FALSE: Graves disease is autoimmune.
True
44
TRUE OR FALSE: Myxedema results from decreased mucopolysaccharides.
False
45
TRUE OR FALSE: Congenital hypothyroidism causes irreversible mental retardation if untreated.
True
46
Which has highest receptor affinity? A. T4 B. T3 C. rT3 D. MIT
B. T3
47
Why is T4 considered a prohormone? A. Not secreted B. Converted to T3 in tissues C. Bound to albumin D. Stored in pituitary
B. Converted to T3 in tissues
48
Reverse T3 function A. Activate receptors B. Counteract thyroid hormone effects C. Stimulate TSH D. Increase metabolism
B. Counteract thyroid hormone effects
49
Which contains iodine stores for months? A. Plasma B. Thyroid gland C. Liver D. Kidney
B. Thyroid gland
50
Iodide trapping mechanism A. Passive diffusion B. Primary active transport C. Secondary active transport D. Facilitated diffusion
C. Secondary active transport
51
Organification means A. Hormone secretion B. Iodine binding to tyrosine C. Protein binding in plasma D. Receptor activation
B. Iodine binding to tyrosine
52
TPO performs all EXCEPT A. Oxidation B. Organification C. Coupling D. Endocytosis
D. Endocytosis
53
Recycling iodine occurs during A. Coupling B. Proteolysis C. MIT/DIT deiodination D. TSH secretion
C. MIT/DIT deiodination
54
Correct order A. Organification → trapping → release B. Trapping → transport → organification → coupling → release C. Release → trapping → coupling D. Transport → trapping → release
B. Trapping → transport → organification → coupling → release
55
Why binding proteins are important A. Increase clearance B. Provide hormone reservoir C. Prevent receptor binding permanently D. Increase degradation
B. Provide hormone reservoir
56
T3 half-life A. 1 hr B. 24 hr C. 3 days D. 8 days
B. 24 hr
57
Feedback regulation is slow because A. Fast degradation B. Gene transcription C. Nerve reflex D. Hormone instability
B. Gene transcription
58
Thyroid hormones act via A. GPCR B. Ion channels C. Nuclear receptors D. Enzyme inhibition
C. Nuclear receptors
59
Increased BMR primarily due to A. ATP synthesis B. Futile cycles C. Fat storage D. Reduced oxygen use
B. Futile cycles
60
Net lipid effect A. ↑ cholesterol B. ↓ cholesterol C. No change D. ↑ triglyceride storage
B. ↓ cholesterol
61
Protein metabolism in hyperthyroidism A. Only synthesis B. Only breakdown C. Both but breakdown predominates D. No change
C. Both but breakdown predominates
62
Sympathetic effects occur due to A. Norepinephrine secretion B. β receptor upregulation C. Parasympathetic stimulation D. Reduced sensitivity
B. β receptor upregulation
63
Cardiac effect A. Negative chronotropy B. Positive inotropy C. AV block D. Bradycardia
B. Positive inotropy
64
Bone effect A. Resorption only B. No effect C. Growth and maturation D. Calcification inhibition
C. Growth and maturation
65
CNS effect A. Sedation B. Coma C. Alertness D. Paralysis
C. Alertness
66
TRH comes from A. Thyroid B. Hypothalamus C. Pituitary D. Liver
B. Hypothalamus
67
TSH stimulates A. Only secretion B. Only synthesis C. All thyroid functions D. Only iodine uptake
C. All thyroid functions
68
Wolff-Chaikoff effect A. Iodine deficiency increases TPO B. Excess iodine suppresses TPO C. T3 suppresses TRH D. TSH suppression
B. Excess iodine suppresses TPO
69
Goiter in hypothyroidism caused by A. Low TSH B. High TSH C. High T3 D. Low iodine only
B. High TSH
70
Graves disease hallmark A. Weight gain B. Exophthalmos C. Bradycardia D. Edema
B. Exophthalmos
71
Myxedema mechanism A. Fat accumulation B. Mucopolysaccharide accumulation C. Water loss D. Protein loss
B. Mucopolysaccharide accumulation
72
↑TSH + ↓T4 A. Primary hypothyroidism B. Secondary hypothyroidism C. Primary hyperthyroidism D. Normal
A. Primary hypothyroidism
73
↓TSH + ↑T4 A. Primary hyperthyroidism B. Secondary hyperthyroidism C. Hypothyroidism D. Subclinical hypothyroidism
A. Primary hyperthyroidism
74
↑TSH + ↑T4 A. Pituitary adenoma B. Graves C. Thyroiditis D. Normal
A. Pituitary adenoma
75
↓TSH + ↓T4 A. Primary hypothyroid B. Secondary hypothyroid C. Hyperthyroid D. Subclinical hyperthyroid
B. Secondary hypothyroid
76
Hyperthyroidism metabolic effect A. Weight gain B. Weight loss C. Hypothermia D. Bradycardia
B. Weight loss
77
Hypothyroidism skin A. Warm moist B. Cold dry C. Sweaty D. Oily
B. Cold dry
78
Congenital hypothyroidism untreated leads to A. Reversible delay B. Normal growth C. Permanent intellectual disability D. Hyperactivity
C. Permanent intellectual disability
(MD 1) Human Physiology
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