Brainscape's Knowledge GenomeTM

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


See full index

Bio 432 > Thyroid Hormone - Final Exam > Flashcards

Thyroid Hormone - Final Exam Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Whats makes up thyroxin?

A

2 tyrosines with ether link and iodine

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

T4

A

Thyroxin

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

How many iodine does T4 have?

A

4

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

What is the active nuclear hormone?

A

T3

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

What is a thyroid hormon non-nuclear effect?

A

Ion channels at the membrane

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

Where does TH get its iodine from? (2)

A
  1. Diet

2. Environment

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

What is one of the most common hormone disease?

A

TH disease

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

Where is TH important for development? (2)

A
  1. Brain

2. Skeletal

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

What is an example of an animo acid derivative?

A

Thyroxine (T4)

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

How can radioactive iodine enter into the body? (2)

A
  1. Ingestion
  2. Inhalation
    - It dissolves in water so its easy to move from the atmosphere to humans
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the effects of normal TH? (5)

A

Normal…

  1. Fetal
  2. Child growth
  3. Brain development
  4. Basal metabolic rate
  5. Metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What 2 hormones do you need to have proper development?

A
  1. Growth hormone

2. Thyroid hormone

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

What is the most common endocrine disease?

A

TH disease

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

What is the cause of hypothyroid?

A

Too little TH

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

What is the cause of hyperthyroid?

A

Too much TH

- Over active thyroid gland

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

Does TH disease affect more men or women? Why?

A

Women (1/7)

- Because of the demands of pregnancy and the monthly cycle (estrogen changes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What has plasticizers shown to do?

A

Shown to bind to TH receptor and have a selective effect on its function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What kind of TH disease is common in cats? How does this effect weight?

A

Hyperthyroidism

- Burns up energy too rapidly and typically suffers weight loss even when having an increase in appetite and food intake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What kind of TH disease is common in dogs? How does this effect weight?

A

Hypothyroidism

- Gains weight while only eating moderately

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Where does thyroid originate?

A

From the pharynx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the thyroid made up of? And what are they lined with?

A
  • Sacs called follicle cells

- Lined with epithelial cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How does TH get to the blood?

A

Through capillaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the thyroglobulin large precursor protein called?

A

Colloid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What adds iodine?

A

Thyroid peroxidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

TPO

A

Thyroid peroxidase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is thyroid peroxidase?

A

It is a membrane bound glycoprotein enzyme that sticks out into colloid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where does thyroglobulin go after it gets degraded?

A

It is free and TH get released into blood on the other side of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

TH synthesis (10 steps)

A
  1. Uptake of iodine (active transport across basement membrane)
    - Iodine is the oxidized by TPO so it can attach to TG
  2. Uptake of amino acids and sugars
    - occurs at the base of the cell from the capillaries
  3. Production of TG
  4. Packaging of TG by golgi conplex
  5. Secretion TG into colloid by exocytosis at aprical surface of cells
  6. Production of iodinated TG
  7. TG with its iodinated tyrosines is stored in the colloid
  8. In the same or neighbouring cell, TG reabsorbed at appropriate time
    - stimulated by TSH
  9. Lysosome fuse with endosome and TG digested
  10. THs are released into capillaries at bottom of cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

TG

A

Thyroglobulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

I-

A

Iodide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is the main form of iodide you eat?

A

Iodized salts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where is iodide taken up and distributed?

A
  • Taken up by the intestines

- Distributed to the extracellular fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Where is iodide distributed?

A

Extracellular fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What clears iodide?

A

The kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What happens to the thyroid gland if lacking iodide?

A

The thyroid gland is not secreting TH and it gets enlarged
- lack of negative feedback loop by TH so TSH keeps pumping up the thyroid gland causing goitre (signs of underlying diseases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What kind of uptake relationship does iodide and thyroid activity have?

A
  • Inversely proportional

- Directly proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How do you treat an overactive thyroid?

A

By giving it a low does of radioactive iodine to kill the thyroid cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How do you treat thyroid cancer?

A

By giving is a high does of radioactive iodine to kill the thyroid cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What does too much iodide cause?

A

Down-regulation of TH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Which thyroid hormone is more and less active?

A
  • More = T4

- Less - T3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What can deiodinase mimic? (2)

A
  1. Testosterone

2. Estrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What happens when deiodinase removes an iodide from the outer ring?

A

It activates it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What enzyme is used to remove iodides from deiodinase outer ring?

A

5’-deiodinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What happens when deiodinase removes an iodide from the inner ring?

A

It deactivates it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What enzyme is used to remove iodides from deiodinase inner ring?

A

5-deiodinase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What is thyroxin more associated with?

A

Blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Where is T3 made?

A

In the membrane of the cell and is then brought into the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

T3

A

Triiodothyronine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

What 3 types of TH are not active in the nucleus?

A
  1. T1
  2. T2
  3. rT3
50
Q

T1

A

Monoiodothyronine

51
Q

T2

A

Diiodothyronine

52
Q

What are 4 physiological importances of deiodinases?

A
  1. Permit local tissue modulation of TH
    - form of regulation
  2. Assist organism adopt to changing states
  3. Regulate TH actions in development
  4. Most T4 is metabolized by deiodination to T3 or rT3, remaining inactivated in live or kidney
53
Q

Where does inactive TH remain? (2)

A
  1. Liver

2. Kidneys

54
Q

What is sulfation?

A

The process of adding groups to make THs more hydrophobic so they can pass the membrane more easily

55
Q

What cells make up thyrotrophs?

A

Anterior pituitary cells

56
Q

What to thyrotrophs release?

A

TSH

57
Q

TSH

A

Thyroid stimulating hormone

58
Q

What does TSH cause? (3)

A
  1. Increase in thyroid gland size
  2. Increase in thyroid vascularization
  3. Stimulation of the thyroid gland function
59
Q

TH axis/regulation steps (5)

A
  1. Neurons from hypothalamus secretes TRH into portal veins that provide a direct route for TRH to the anterior lobe cells
  2. Thyrotrophs in the anterior pituitary are stimulated by TRH and secrete TSH into the pituitary venous system
    - inhibited by somatostatin from hypothalamus
  3. Follicular cells in thyroid are stimulated by TSH and secrete TH into the capillaries for transport to target tissues or via blood stream back to the hypothalamus and pituitary
  4. TH transported into cells to target tissues
    - In the nucleus TR/T3 binding to TREs regulates genes via transcription up or down
    5a. Negative feedback: Serum T3 and T4 levels regulate TRH and TSH
    5b. Negative feedback: excess iodide inhibits
60
Q

TRE

A

Thyroid response element

61
Q

What 2 factors stimulate TRH?

A
  1. Circadian rhythm

2. Cold

62
Q

What inhibits TSH? (2)

A
  1. Glucocorticoids

2. Chronic illness

63
Q

What can either stimulate or block TH regulation?

A

Autoimmune Ab TSH receptors on the thyroid

64
Q

What does TSH stimulate? (3)

A
  1. Follicle growth
  2. TH synthesis
  3. TH secretion
65
Q

Is TH hydrophobic or hydrophilic?

A

Hydrophobic

66
Q

What does TH need in order to cross the membrane?

A

Needs transport proteins in hydrophilic blood

67
Q

What is a good source of TH and why?

A
  • Blood binding protein

- Cause it binds tightly and keeps it stable

68
Q

TBG

A

Thyroid binding globulin

69
Q

What tightly binds T3 and T4?

A

Thyroid binding globulin

70
Q

What is TBG deficiency?

A
  • Is a genetic condition that typically does not cause any health problems. Thyroxine-binding globulin is a protein that carries hormones made or used by the thyroid gland
  • Reaches equilibrium of free TH, but low total TH since Th is not stabilized so its degraded quickly
71
Q

What is the result of thyroid binding globulin deficiency?

A

Hypothyroidism

72
Q

What is the half life of TH in the plasma?

A

7 days

73
Q

What does T4 bound to blood binding proteins do?

A

Can store it for later use

74
Q

THBP

A

Thyroid hormone binding proteins

75
Q

What does TH bind to?

A

Cytoplasmic THBP

76
Q

What are THBP?

A

They are multifunctional proteins that bind TH with ranging affinities

77
Q

What are the 3 domains nuclear receptors have?

A
  1. Amino terminal domain
  2. DNA binding domain
  3. Ligand binding domain (at C terminal)
78
Q

What does a mutation in the ligand binding domain cause?

A

TH resistance

79
Q

What are 2 important differences from steroid receptors to thyroid receptors?

A
  1. TRs dont use heat chock proteins

2. TRs stay bound to DNA in the nucleus

80
Q

What is the difference between a ligand and a receptor?

A
  • Ligand is a general term for any molecule that binds to another molecule
  • Receptor is a protein to which a signalling molecule that binds specifically and stimulates a particular response by a cell
81
Q

What are the 2 zinc fingers functions? (2)

A
  • 1 zinc finger binds DNA

- The other zinc finger is used for dimerization

82
Q

How do the 2 zinc bind to zinc?

A

Through cysteine residue (- charge)

83
Q

HRE

A

Hormone response element

84
Q

Where does specificity come from in the hormone response element? (5)

A
  1. Timing
    - receptor expression/ hormone signal
  2. Context
    - cell type, surrounding sequence
  3. Cofactor expression/activation
  4. Exact spacing
  5. Sequence of HRE
85
Q

What does TR binds as?

A

A heterodimer, preferentially with RXR

86
Q

What do half sites bind as?

A

Homodimers

87
Q

What makes up a homodimer?

A

2 thyroid receptors

88
Q

What makes up a heterodimer?

A

1 thyroid recetor and 1 retinoic X receptor

89
Q

What do transcription complexes do? (2)

A
  1. Bind

2. Stabilize

90
Q

How do receptors bind to DNA?

A

As dimers without hormones

91
Q

When do hormones bind and what happens?

A
  • Hormones bind later

- It changes and activates its state

92
Q

What does it mean if the receptor cant bind to the DNA or ligand?

A

Its an antagonist

93
Q

What happens if the TRE is positive?

A

Then TR repressing along, and the ligand TH binds and together activating

94
Q

What happens if the TRE is negative?

A

TR can be activating without TH and repressing with TH

95
Q

Corepression and coactivation of nuclear receptors steps (3)

A
  1. Corepressor complex: histone deacetylases (HDACs) close chromatin, repressing transcription
    - acetyl groups is bulky and removes the positive charge on the histone to decrease the interaction with a negative phosphate on the DNA
  2. Ligand binds and ATP is used to remodel the chromatin
    3a. Coactivators recruit histone acetyltransferases (HATSs), it opens up chromatin for transcription
    3b. Large coactivator complexes for TR bridge with basal transcription machinery
    - eg) TATA binding protein and other general TF
96
Q

HAT

A

Histone acetyltransferase

97
Q

What 2 factors are important for remodelling and development? What are 3 examples?

A
  1. Proliferation
  2. Apoptosis
    - -> creates turn over
  3. TH causes increase transcription of caspases of caspases for apoptosis
  4. Caspase 3 and cyclins for proliferation
  5. Cyclin D to move to S phase for DNA synthesis
98
Q

What happens if you mess with proliferation and apoptosis?

A

Leads to diseases

99
Q

What 2 factors increase due to TH?

A
  1. Proliferation

2. Apoptosis

100
Q

What do cyclins help with?

A

Going through the cell cycle

101
Q

What are many cellular pathways and functions regulated by?

A

TH

  • 25 upregulate
  • 50 downregulate
102
Q

What can TR beta do?

A

Autoregulate

- represses without ligand and then activates itself

103
Q

What 2 factors are upregulated by TR beta?

A
  1. TR alpha

2. 5’-deiodinases

104
Q

Do nuclear receptors have non-genomic and/or genomic features?

A
  • Non-genomic = no

- Genomic = yes

105
Q

Does timing have non-genomic and/or genomic features?

A
  • Non-genomic = rapid (secs-hours)

- Genomic = slow enough for transcription (2hrs+)

106
Q

Do TH forms have non-genomic and/or genomic features?

A
  • Non-genomic = All forms of TH

- Genomic = T3

107
Q

Does amplitude have non-genomic and/or genomic features?

A
  • Non-genomic = small (1 to several fold)

- Genomic = Huge (multifold)

108
Q

Does signal transduction have non-genomic and/or genomic features?

A
  • Non-genomic = Yes

- Genomic = No

109
Q

What are intergrins?

A

They are receptors that mediate attachment between a cell and other cells of the extracellular matrix

110
Q

What does rapid intracellular effects include? (5)

A
  1. Ion flux
  2. Translation efficiency in ER
  3. Mitochondria activity (especially in the liver)
  4. Glucose and amino acid uptake
  5. Actin polymerization (remodelling, neural connections, cell movement, intracellular trafficking, muscle contraction, pseudopod formation, ect)
111
Q

What are 5 examples of TH non-genomic effects?

A
  1. Calmodulin
  2. Integrins
  3. PIP3
  4. cAMP
  5. Protein kinase
112
Q

How does T3 enter the cell?

A

By specific transporters

113
Q

What does T3 act in once it enters the cell? Via?

A

Acts in the nucleus via TR

114
Q

What doe T3 act directly on?

A

Ion channels at the membrane

115
Q

What action does TH have on cardiac myocytes?

A

Increases heart rate

116
Q

How can TH affect TR in the nucleus?

A

Through phosphorylation cascades

117
Q

What happens when TR is phosphorylated?

A

It is activated and its co-repressed proteins are dissociated

118
Q

CDK

A

Cyclin dependent kinase

119
Q

MAPK

A

Mitogen activated protein kinase

120
Q

HDAC

A

Histone deacetylase

Bio 432 (19 decks)

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