Endocrinology Part 2 (Thyroid and Parathyroid) Flashcards
(249 cards)
1
Q
Thyroid is butterfly-shaped due to?
A
bilobed structure
2
Q
type of T3 that is biologically inactive
A
rT3 (reverse T3)
3
Q
Location of iodine in T3
A
3, 5, 3’
4
Q
Location of iodine in T4
A
3, 5, 3’, 5’
5
Q
generation test that detects very minute amount of TSH
A
3rd gen
6
Q
Due to parathyroid gland location, it is considered as?
A
smallest endocrine gland
7
Q
Butterfly-shaped glands found in the lower anterior neck
A
thyroid gland
8
Q
Tissue that connects 2 lobes of thyroid gland
A
isthmus
9
Q
specific location of butterfly-shaped glands
A
lower anterior neck
10
Q
functions of thyroid gland
A
Controls biosynthesis and release of TH from thyroglobulin
Regulates carbohydrates, proteins and lipid metabolism
Acts on CNS (by brain maturation and dev’t)
Stimulates the heart
Physical growth and development
Controls basal body temperature
11
Q
how thyroid gland act on CNS
A
by brain maturation and development
12
Q
body temp when there is ↑ TH
A
↑ body temp
13
Q
oxygen consumption when ↑ TH
A
↑ O2 consumption / demand
(more cells consume O2)
14
Q
hollow spheres of thyroid gland
A
colloid follicles
15
Q
what type of tissue is follicle cells?
A
squamous epithelial cells, cuboidal cells
16
Q
aka cuboidal cells
A
thyroid follicular cells
17
Q
located within spherical structure
A
colloids
18
Q
content of follicle cells, a gel-like matrix
A
colloids
19
Q
has thyroglobulin within it
A
colloids
20
Q
follicle cells are important for ______ synthesis
A
T3 and T4 synthesis
21
Q
major component of thyroid colloids
A
thyroglobulin
22
Q
important substance for TH synthesis
A
thyroglobulin
23
Q
composition of thyroglobulin
A
2 tyrosine backbone
Each tyrosine backbone has 1 iodine binding site
24
Q
how many iodine binding site is in each thyroglobulin
A
2
25
structures responsible for calcitonin production
parafollicular C cells
26
2 biologically active hormones
Triiodothyronine (T3)
Tetraiodothyronine/Thyroxine (T4)
27
more biologically active TH
Triiodothyronine (T3)
28
T3 pre-hormone
Tetraiodothyronine/Thyroxine (T4)
29
less biologically active (requires deiodination to become more biologically active)
Tetraiodothyronine/Thyroxine (T4)
30
enumerate steps for TH synthesis
1. Iodide uptake
2. Iodide → Iodine (oxidized)
3. Iodine Uptake
4. Iodination of tyrosine (thyroglobulin)
5. Coupling reaction of iodinated tyrosine
31
what is acquired from diet that is necessary for TH synthesis
iodide
32
Iodide (I2) from diet will enter?
follicular cells (within follicular cells is colloid; colloid has thyroglobulin)
33
site of oxidation from iodide to iodine
colloid
34
process where iodine attaches to the tyrosine backbone of thyroglobulin
iodination of tyrosine (thyroglobulin)
35
1 iodine attached to thyroglobulin
monoiodothyronine
36
2 iodine attached to thyroglobulin
diiodothyronine
37
process of combination of two thyroglobulin with iodine
Coupling reaction of iodinated tyrosine
38
monoiodothyronine + diiodothyronine
triiodothyronine
39
diiodothyronine + diiodothyronine
tetraiodothyronine
40
important substance for TH synthesis
Iodine
41
Iodine deficiency indicates?
TH deficiency
42
removes 1 iodine atom from OUTER tyrosyl ring of T4 to produce T3 (biologically active form)
Monodeiodination
43
enzyme for the removal of 1 iodine atom from outer tyrosyl ring of T4 to produce T3
monodeiodinase
44
Combination of 2 thyroglobulin will form?
2 rings
45
Removal of iodine from outer ring produces?
Removal of iodine from inner ring produces?
T3
rT3 (reverse T3)
46
biologically inactive TH
rT3 (reverse T3)
47
regulation of TH follows this axis
hypothalamic pituitary thyroidal axis
48
secretes thyrotropin-releasing hormone (TRH)
hypothalamus
49
secretes thyroid-stimulating hormone (TSH)
pituitary gland
50
gland that produce TH (T3 & T4)
thyroid gland
51
after production of TH by thyroid gland? what is the next process?
TH (T3 & T4) acts on peripheral tissues with specific receptors
52
affected gland if a TH disorder is PRIMARY
thyroid
53
affected gland if a TH disorder is SECONDARY
pituitary
54
affected gland if a TH disorder is TERTIARY
hypothalamus
55
TH disorder classification if there is:
↑ TH
N/↓ TRH, TSH
primary hyperthyroidism
56
TH disorder classification if there is:
↓ TH
N/↑ TRH, TSH
primary hypothyroidism
57
TH disorder classification if there is:
↑ TSH, TH
N/↓ TRH
secondary hyperthyroidism
58
TH disorder classification if there is:
↓ TSH, TH
N/↑ TRH
secondary hypothyroidism
59
TH disorder classification if there is:
↑ TRH, TSH, TH
tertiary hyperthyroidism
60
TH disorder classification if there is:
↓ TRH, TSH, TH
tertiary hypothyroidism
61
hormone levels in primary hyperthyroidism
↑ TH
N/↓ TRH, TSH
62
hormone levels in primary hypothyroidism
↓ TH
N/↑ TRH, TSH
63
hormone levels in secondary hyperthyroidism
↑ TSH, TH
N/↓ TRH
64
hormone levels in secondary hypothyroidism
↓ TSH, TH
N/↑ TRH
65
hormone levels in tertiary hyperthyroidism
↑ TRH, TSH, TH
66
hormone levels in tertiary hypothyroidism
↓ TRH, TSH, TH
67
chemical name of T3
3, 5, 3’-triiodothyronine
68
Accounts for 20% of total TH synthesized
TRIIODOTHYRONINE (T3)
69
have the most active hormonal activity
TRIIODOTHYRONINE (T3)
70
Functions of T3
* Metabolic rate of every cell of the body
* Encourages cellular differentiation
* Tissue growth and development
* ↑ oxygen consumption
* Calorie and Vitamin/Mineral metabolism
* Indicator of hyperthyroidism recovery
* Involve brain maturation
* Cause ↑ heat production
71
Indicator of hyperthyroidism recovery
TRIIODOTHYRONINE (T3)
72
TH of heat intolerant individuals
increased (in cases of hyperthyroidism)
73
Reference Ranges of T3
Adult: 60-160 ug/dL
Children (1-14 y.o): 105 – 245 ng/dL
74
reason why there is increased values of T3 in children
T3 & T4 involvement in tissue growth and dev’t
75
chemical name of T4
3, 5, 3', 5' tetraiodothyronine
76
Accounts for 80% of total TH synthesized
TETRAIODOTHYRONINE (T4)
77
T/F
↑ T4 ↑TSH (vice versa)
F
↑ T4 inhibit TSH
78
Reference Ranges of T4
Adult: 5.5 – 12.5 ug/dL
Neonates: 11.8 – 22.6 ug/dL
79
Different Forms of Iodine in the Body
tyrosine
thyroxine (T4)
triiodothyronine (T3)
reverse T3 [inactive]
80
THYROID BINDING PROTEINS
Thyroxine Binding Globulin
Thyroxine Binding Prealbumin
Albumin
81
major transporter for T3
Thyroxine Binding Globulin
82
bind 70-75% of T4
Thyroxine Binding Globulin
83
binds 15-20% of T4
Thyroxine Binding Prealbumin
84
T3 transport protein
Albumin
85
bind 10% of T4
Albumin
86
T/F
TH can be free or bound
T
87
percentage of protein-bound TH and free TH
99.9% – protein-bound TH
0.1% – free (unbound) TH
88
percentage of free T4 (FT4)
0.04%
89
percentage of free T3 (FT3)
0.4%
90
thyroid binding protein levels if ↑ estrogen
↑ TBP (allows free TH to bind, ↑ bound TH)
91
total TH refers to
T3 & T4
92
Most useful test for assessing thyroid function
Thyroid Stimulating Hormone/Thyrotropin (TSH)
93
Used to differentiate primary hypothyroidism from secondary hypothyroidism
Thyroid Stimulating Hormone/Thyrotropin (TSH)
94
Used to monitor and adjust thyroid hormone replacement therapy (3rd Gen)
Thyroid Stimulating Hormone/Thyrotropin (TSH)
95
generation test with 0.1 mU/L detection limit
Second Generation
96
generation test with 0.01 mU/L detection limit (more sensitive)
Third Generation
97
generation test for research purposes only (not for diagnosis)
Fourth Generation
98
what are measured in Serum T3 and T4
o Total T3 and T4
o Free T3 and T4 (FT3, FT4)
99
methods for Serum T3 and T4
o Radioimmunoassay
o Chemiluminometric assay
o Immunometric technique
100
Measures relationship between TSH & TRH secretions
Thyrotropin-Releasing Hormone (TRH)
101
Used to confirm euthyroid Grave’s disease (type of hyperthyroidism)
Thyrotropin-Releasing Hormone (TRH)
102
Thyrotropin-Releasing Hormone (TRH) is increased during? decreased during?
Increased: primary hypothyroidism
Decreased: hyperthyroidism
103
Glycoprotein synthesized and secreted only by thyroid follicular cells
Thyroglobulin
104
Proof of presence of thyroid tissues / thyroid follicular cells
Thyroglobulin
105
Ideal tumor marker for thyroid cancer patients
Thyroglobulin
106
Post-operative marker of thyroid cancer
Thyroglobulin
107
Surgical removal of thyroid gland (2 lobes removed) leading to NO TGB in circulation
Bilateral thyroidectomy
108
methods for thyroglobulin
Immunoassays
109
Measures remaining free binding sites
T3 Resin Uptake
110
Analyzes the capacity of TBG to bind TH
T3 Resin Uptake
111
Indirect measurement of the number of free binding sites on the TBG molecules
T3 Resin Uptake
112
thyroid binding site when ↓ TH (not saturated)
↑
113
thyroid binding site when ↑ TH (saturated)
↓
114
Indirectly assesses conc. of circulating FT4
Free Thyroxine Index (FT4I)
115
a test that is not measured; requires computation
Free Thyroxine Index (FT4I)
116
formula for Free Thyroxine Index
FT41 = total T4 x T3 resin uptake
117
test that utilizes antibodies for screening
Thyroid Antibody Screen
118
antibodies used in Thyroid Antibody Screen
Anti-TSH receptor (TSH receptor antibody)
Antithyroglobulin
Anti-thyroid peroxidase (anti-TPO)
119
antibody associated with Grave’s disease
Anti-TSH receptor (TSH receptor antibody)
120
antibody associated with some if not all autoimmune hypothyroidism
Antithyroglobulin
121
antibody associated with Hashimoto’s thyroiditis
Anti-thyroid peroxidase (anti-TPO)
122
Measures pituitary TSH stores
TRH Stimulation Test
123
Conclusive test for hyperthyroidism
TRH Stimulation Test
124
process of TRH Stimulation Test
o Collect blood
o Inject 500 ug TRH (intravenous) – stimulate pituitary gland to secrete TSH
o Collect blood
o RESULT:
* Normal: ↑ TSH
* Hyperthyroidism: no ↑ (same level)
125
intravenous TRH injected during stimulation test will stimulate this gland? what is the hormone secreted by that gland?
pituitary gland
TSH
126
reason why hyperthyroidism has no increase (same level) during TRH stimulation test
pituitary is not stimulated by TRH injection (ex: if secondary), pituitary gland is already producing its own TSH regardless of TRH stimulation; same rate of production
127
Measures thyroid gland ability to trap iodine
Radioactive Iodine Uptake (RAIU)
128
Test where thyroid gland absorbs/uptake radioactive iodine
Radioactive Iodine Uptake (RAIU)
129
Uptake of iodine by thyroid gland is stimulated by
TSH
130
↑ iodine uptake signifies?
metabolically active gland (produces TH)
131
↓ iodine uptake signifies?
metabolically inactive gland (no TH production)
132
type of nodules with ↑ RAIU
Hot nodules
133
type of nodule found in thyroid gland
hot nodules
134
type of nodule that takes up large amt. of injected radioactive iodine
hot nodules
135
type of nodule that is less likely cancerous
hot nodules
136
type of nodules with ↓ / No RAIU
Cold/Indeterminate/Intermediate
137
type of nodules that is cancerous
Cold/Indeterminate/Intermediate
138
↑ RAIU, undetectable TSH indicates?
autonomous thyroid gland activity; takes iodine even TSH absence
139
used for thyroid anatomy assessment
Thyroid Ultrasound
140
used for characterization of palpable abnormalities
Thyroid Ultrasound
141
during thyroid ultrasound, thyroid nodule size that can be seen
Thyroid nodules (<1cm) - NORMAL
142
Most accurate tool in thyroid nodule evaluation
Thyroid needle biopsy/fine needle aspiration biopsy (FNAB)
143
First test to be performed for thyroid abnormalities
Thyroid needle biopsy/fine needle aspiration biopsy (FNAB)
144
used for identification and treatment of thyroid malignancy
Thyroid needle biopsy/fine needle aspiration biopsy (FNAB)
145
FNAB is assisted by either of these 2 methods
Nodule palpation
Ultrasound
146
TH deficiency
HYPOTHYROIDISM
147
hypothyroidism usually refer to this disorder classification
primary hypothyroidism
148
Hypothyroidism symptoms
o Thyroid gland enlargement/goiter
o Fatigue
o Impairment of mental process
o Loss of appetite
o Myxedema (↓ cardiac output)
o Cold intolerance
o Weight gain
149
Thyroid gland enlargement/goiter in hypothyroidism is due to?
↑ TSH (stimulates cell growth)
150
Impairment of mental process in hypothyroidism is due to?
slowed down CNS activity
151
Loss of appetite in hypothyroidism is due to?
multiple organ defect
152
How is TH associated with Myxedema (↓ cardiac output) in hypothyroidism?
TH regulates heart rate
153
mechanism of having cold intolerance in hypothyroidism
↓ TH : ↓ body temp
154
mechanism of weight gain in hypothyroidism
Slow macromolecule metabolism
155
Inadequate secretion of TH by thyroid gland
Primary Hypothyroidism
156
causes of Primary Hypothyroidism
o Lack of dietary iodine
o Thyroid tissue destruction (inability to produce TH)
o Autoantibodies
157
Laboratory Results of primary hypothyroidism
Decreased: T3, T4, FT3, FT4, FT41, T3 uptake
Increased: TSH, TRH
158
conditions associated with primary hypothyroidism
Hashimoto’s Thyroiditis
Congenital Hypothyroidism/Cretinism
Myxedema (low cardiac output)
159
aka Hashimoto’s Thyroiditis
Chronic Lymphocytic Thyroiditis
(massive infiltration of thyroid gland by lymphocytes)
160
Most common form of primary hypothyroidism; autoantibodies bind to cell membrane causing cell lysis and inflammatory reactions
Hashimoto’s Thyroiditis
161
manifestation of Hashimoto’s Thyroiditis
goiter
162
Laboratory Results of Hashimoto’s Thyroiditis
Decreased: T3, T4, FT3, FT4, FT41, T3 uptake
Increased: TSH, TRH
Anti-TPO positive
163
aka Congenital Hypothyroidism
Cretinism
164
Defect in development or function of thyroid gland
Congenital Hypothyroidism/Cretinism
165
symptoms of Congenital Hypothyroidism/Cretinism
Retarded physical and mental development
166
most common feature of Congenital Hypothyroidism/Cretinism
dwarfism
167
result if congenital hypothyroidism/cretinism is left untreated within 3 months
Irreversible neurologic & mental deficiency
168
Laboratory results of congenital hypothyroidism/cretinism
Decreased: T3, T4
Increased: TSH
169
Peculiar nonpitting swelling [no indentation after pressure] of skin
Myxedema (low cardiac output)
170
Sever form of myxedema
Myxedema coma
171
Clinical features of myxedema
o Puffy face
o Weight gain, slow speech, eyebrows thinned, dry and yellow skin, anemia
172
Decrease TSH production leading to ↓ serum levels of TH
Secondary Hypothyroidism
173
Laboratory results of Secondary Hypothyroidism
Decreased: T3, T4, FT3, FT4, FT41, T3 uptake, TSH
Increased: TRH
174
lack of TRH production (caused by hypothalamic failure)
Tertiary Hypothyroidism
175
Laboratory results of tertiary hypothyroidism
all TH Decreased: T3, T4, FT3, FT4, FT41, T3 uptake, TSH, TRH
176
Asymptomatic form of hypothyroidism
Subclinical Hypothyroidism
177
Lab results of Subclinical Hypothyroidism
Normal: FT3, FT4
Slightly increased: TSH
178
aka HYPERTHYROIDISM
THYROTOXICOSIS
179
T/F
↑ TH is NOT toxic to all cells
F
↑ TH = toxic to all cells
180
Caused by excessive TH in circulation
HYPERTHYROIDISM / THYROTOXICOSIS
181
Causes overactive cells
HYPERTHYROIDISM / THYROTOXICOSIS
182
symptoms of hyperthyroidism / thyrotoxicosis
o Weight loss
o Loss of muscle mass
o Hyperactivity yet quick fatigability
o Insomnia
o Increased sweating
o Nervousness
o Palpitations
o Goiter
o Exophthalmia (bulging of eyes)
183
weight loss during hyperthyroidism is due to
Rapid macromolecule metabolism
184
hyperactivity yet quick fatigability during hyperthyroidism is due to
↑ O2 demand
185
insomnia during hyperthyroidism is due to
↑ CNS activity
186
increased sweating during hyperthyroidism is due to
↑ body temp
187
nervousness during hyperthyroidism is due to
↑ CNS activity
188
palpitations during hyperthyroidism is due to
↑ cardiac output
189
goiter during hyperthyroidism is due to
↑ TH
190
T/F
Both hypothyroidism and hyperthyroidism manifest goiter
T
hyperthyroidism: due to ↑ TH
hypothyroidism: due to ↑ TSH
191
Dangerously HIGH TH levels leading to STROKE
Thyroid Storm
192
Dangerously HIGH TH levels leads to STROKE due to
↑ CNS output
↑ Body temperature
↑ Cardiac output
193
Group of syndromes caused by ↑ free TH in circulation
Thyrotoxicosis
194
FT3 level in T3 Thyrotoxicosis / Plummer’s Disease
↑
195
aka T3 Thyrotoxicosis
Plummer’s Disease
196
FT4 level in T3 Thyrotoxicosis / Plummer’s Disease
N
197
TSH level in T3 Thyrotoxicosis / Plummer’s Disease
↓
198
FT3 level in T4 Thyrotoxicosis
N/↓
199
FT4 level in T4 Thyrotoxicosis
↑
200
TSH level in T4 Thyrotoxicosis
↓
201
a primary hyperthyroidism; autoimmune disorder
Grave’s Disease
202
Prevalence of Grave's dse
5-6x more in female than male
203
Clinical features of Grave's dse
Exophthalmos (bulging of eye)
Pretibial myxedema
204
Laboratory Results of Grave's dse
Increased: T3, T4, FT41, T3 uptake
Normal/Decreased: TSH
Anti-TSH receptor positive
205
condition where thyroid turns into woody or stony-hard mass (calcification of thyroid gland)
Reidel’s Thyroiditis
206
hyperthyroidism with no clinical symptoms
Subclinical Hyperthyroidism
207
Lab result of Subclinical Hyperthyroidism
Normal: FT3, FT4
Decreased: TSH
208
aka De Quervain Thyroiditis
Subacute granulomatous thyroiditis
Subacute nonsuppurative thyroiditis
209
results to painful/inflammed TH gland
De Quervain Thyroiditis/
Subacute granulomatous thyroiditis/
Subacute nonsuppurative thyroiditis
210
Lab result of De Quervain Thyroiditis
↑ ESR & thyroglobulin
Anti-TPO negative
211
Produced by parafollicular C cells of thyroid gland
CALCITONIN
212
Participated in calcium homeostasis by responding to hypercalcemia
CALCITONIN
213
Indirectly regulate phosphate by stimulating renal reabsorption of phosphorus (↑ PO4-)
CALCITONIN
214
Calcitonin is (hypercalcemic, hypocalcemic) and (hyperphosphatemic, hypophosphatemic)
hypocalcemic, hyperphosphatemic
215
actions of calcitonin as hypocalcemic agent
o Stimulates renal excretion of Ca2+
o Depresses release of Ca2+ from bone (↓ bone resorption)
o Inhibits bone-dissolving activity of osteoclasts (bone macrophage)
216
LABORATORY ANALYSES OF CALCITONIN
Serum Calcitonin
Pentagastrin Stimulation Test
217
Serum Calcitonin analysis is a marker for
Medullary thyroid carcinoma (MTC)
218
required period and repetition of serum calcitonin measurement
before & 6 mos after thyroid surgery
219
test used for MTC diagnosis
Pentagastrin Stimulation Test
220
Smallest endocrine gland
PARATHYROID GLAND
221
Bilaterally located in the posterior portion of thyroid gland
PARATHYROID GLAND
222
T/F
Most people have 4 PTH gland, some 2 or 8
T
223
Modulation of parathyroid gland
Free-Standing Endocrine Gland System
(regulation influenced by substance it regulates)
224
Regulates Blood Calcium and phosphate (sensitive to Ca2+, PO4- level changes; immediate production)
PTH
225
PTH metabolism of both calcium and phosphorus is done by these (2)
kidney
bone
226
PTH is (hypercalcemic, hypocalcemic) and (hyperphosphatemic, hypophosphatemic)
hypercalcemic, hypophosphatemic
227
Stimulates conversion of Vit D activated Vit D3
PTH
228
how PTH act as hypercalcemic agent
In Bone: ↑ bone resorption of Ca2+ into plasma
In Kidney: ↑ renal reabsorption of Ca2+
229
it stimulates bone resorption
osteoclast (bone macrophage)
230
LABORATORY ANALYSES OF PTH
PTH C-TERMINAL ANALYSIS
PTH N-TERMINAL ANALYSIS
231
Examines intact/whole PTH molecule
PTH C-TERMINAL ANALYSIS
232
Lab analysis specific for detecting hyperparathyroidism
PTH C-TERMINAL ANALYSIS
233
Measures both the whole (intact) PTH molecule and amino-terminal fragments in the serum
PTH N-TERMINAL ANALYSIS
234
Inability to maintain Ca2+ in blood without Ca2+ supplementation
~ ↓ PTH, ↓ Ca2+
HYPOPARATHYROIDISM
235
feature of hypoparathyroidism? how to assess?
tetany
Chvostek’s sign – facial contraction (tap)
Trousseau’s sign – carpal spasm
236
causes of hypoparathyroidism
Post-surgical cases: accidental injury to parathyroid gland
Autoimmune parathyroid destruction
237
condition with ↓ PTH (hyposecretion due to parathyroid gland defect)
Primary Hypoparathyroidism
238
condition with ↓ serum Ca2+, ↑ Phosphorus
Idiopathic Hypoparathyroidism
239
condition having lack of responsiveness of PTH by renal system (kidney) – ↓ PTH
Pseudohypoparathyroidism
240
All classifications of HYPERPARATHYROIDISM are always accompanied by
phosphaturia, presence of PO4- crystals in urine
241
Most common cause of hypercalcemia
Primary hyperparathyroidism
242
This condition occur due to parathyroid adenoma
Primary hyperparathyroidism
243
Lab result of Primary hyperparathyroidism
Increased: PTH, Ionized Ca2+
*Ca2+ also increased since it is hypercalcemic
244
Develops in response to hypocalcemia
Secondary hyperparathyroidism
245
causes of Secondary hyperparathyroidism
Vitamin D deficiency
Chronic renal failure
246
Lab result of Secondary hyperparathyroidism
Increased: PTH
Decreased: Ionized Ca2+
247
Occurs with secondary hyperthyroidism
Tertiary hyperparathyroidism
248
condition with Ca2+ phosphates precipitate (crystals) in soft tissues
Tertiary hyperparathyroidism
249
Lab Result of Tertiary hyperparathyroidism
Phosphates level: N/↑
