THYROID GLAND Flashcards
It is a butterfly gland found in the lower anterior neck
Thyroid gland
one important gland of the body that is responsible in the production of thyroid hormone and calcitonin.
Thyroid gland
The thyroid gland is an important gland of the body that is responsible for what?
responsible in the production of thyroid hormone and calcitonin
The thyroid gland is a butterfly gland found where?
found in the lower anterior neck
The thyroid gland is also called a ____ gland
butterfly gland
Thyroid hormones require what for their synthesis?
iodine
Thyroid hormones require iodine for what?
for the their [thyroid hormones] synthesis
These require iodine for their synthesis.
Thyroid hormones
This combines with the protein thyroglobulin to form hormone precursors
Iodine
The iodine combines with the what protein to form hormone precursors that in turn combine to form T3 and T4?
thyroglobulin
The iodine combines with the protein thyroglobulin to form what?
to form hormone precursors
The iodine combines with the protein thyroglobulin to form hormone precursors
that in turn combine to form what?
to form T3 and T4
These are either stored within the follicle or released into the bloodstream.
Thyroid hormones
What are the 2 destinations of thyroid hormones?
- either stored within the follicle
- or released into the
bloodstream.
Thyroid hormones are may stored within the what?
follicle
Thyroid hormones may be released into the what?
bloodstream
In the blood, this eventually gives up an iodine molecule and forms T3.
most T4
In the blood, most T4 eventually gives up an/a what?
gives up an iodine molecule
In the blood, most T4 eventually gives up an iodine molecule and forms what?
T3
There is much more circulating T3 than T4.
True or false
true
Approximately how many percent of circulating T3 and T4 is bound to protein?
98%
Approximately 98% of circulating T3 and T4 is bound to what?
bound to protein
Approximately 98% of what is bound to protein?
98% circulating T3 and T4
Approximately 98% of circulating T3 and T4 is bound to protein, including what?
- thyroxine-binding globulin (TBG)
- thyroxine-binding albumin.
this is the physiologically active
fraction.
when some hormone remains unbound or free
What do you call when some hormone remains unbound or free?
physiologically active
fraction.
regulation of T3 and T4
This is released by the brain and stimulates the release of TSH (thyrotropin) from the pituitary gland
Thyroid-releasing hormone (TRH)
Thyroid-releasing hormone (TRH) is released by what?
released by the brain
It stimulates the
release of TSH (thyrotropin) from the pituitary gland.
Thyroid-releasing hormone (TRH)
Thyroid-releasing hormone (TRH) stimulates the release of what?
release of TSH (thyrotropin)
Thyroid-releasing hormone (TRH) stimulates the release of what?
release of TSH (thyrotropin)
Thyroid-releasing hormone (TRH) stimulates the release of TSH (thyrotropin) from the what?
from the pituitary gland
It stimulates iodine uptake
TSH
TSH stimulates what?
iodine uptake
TSH stimulates iodine uptake by the what?
by the thyroid gland
This causes the release
of T3 and T4 from the thyroid gland.
TSH
TSH causes the release
of what?
causes the release
of T3 and T4
TSH causes the release
of T3 and T4 from the what?
from the thyroid gland
What is the cause of the “shut off” the release of TSH from the pituitary gland, decreased levels induce TSH release?
Due to high serum levels of free T3 and T4
What is the effect of high serum levels of free T3 and T4?
“shut off” the release of TSH from the pituitary gland
High serum levels of bound T3 and T4 “shut off” the release of TSH from the pituitary gland, increased levels inhibit TSH release
true or false
free T3 and T4; decreased levels INDUCE TSH release
FALSE
These levels of T3 and T4 induce TSH release
decreased levels
High serum levels of free T3 and T4 “shut off” the release of TSH from the what?
from the pituitary gland
What organ released TSH?
pituitary gland
the concentration of TSH depends on what?
depends on how much T4 and T3 are in the blood.
Calcitonin is another hormone produced by the pituitary gland.
true or false
produced by the thyroid gland
false
It participates in regulating the amount of calcium in the blood and maintaining calcium homeostasis
Calcitonin
What are the 2 roles of Calcitonin?
- It participates in regulating the amount of calcium in the blood
- maintains calcium homeostasis
What are the 2 types of cells in the Thyroid gland?
- Follicular cells
- Parafollicular cells
Parafollicular cells are also called …
C cells
Follicular cells pertain to what?
T3 and T4
Parafollicular cells pertain to what?
Calcitonin
It is a glycoprotein
Thyroglobulin
it acts as a preformed matrix containing tyrosyl group
Thyroglobulin
Thyrglobulin acts as a what?
acts as a preformed matrix containing
tyrosyl group
Thyrglobulin acts as a preformed matrix containing what?
containing tyrosyl group
it is stored in the follicular colloid of the thyroid gland.
Thyroglobulin
Thyroglobulin is stored in where?
stored in the follicular colloid of the thyroid gland.
Iodination of tyrosine residues in thyroglobulin results in formation of what?
- monoiodotyrosine (MIT)
- diiodotyrosine (DIT).
This results in the formation of monoiodotyrosine (MIT) and diiodotyrosine (DIT).
Iodination of tyrosine residues in thyroglobulin
These kind of hormones are metabolically inactive
Protein bound hormones
Protein bound hormones are metabolically inactive
True or false
true
These are the physiologically active portions of the thyroid hormones.
Free Hormones
What are the free hormones?
FT3 and FT4
What happens when iodide sources are diminished?
- MIT is produced in greater quantities
- leading to increased T3 formation and release.
It is produced by removal of one iodine from the inner ring of
T4
Reverse T3
How is reverse T3 produced?
produced by removal of one iodine from the inner ring of
T4
Reverse T3 is produced by removal of one iodine from what?
from the inner ring of T4
Reverse T3 is produced by removal of how many iodines?
1
Reverse T3 is metabolically active
True or false
metabolically inactive
false
It is the product of T4 metabolism.
Reverse T3
Iodine intake of how much is an indication of the deficiency of hormone secretion?
Iodine intake below 50ug/day
Iodine intake below 50ug/day is an indication of what?
indication of the deficiency of
hormone secretion.
How does the regulation of thryoid hormone secretion happen?
- Hypothalamus
- Thyroprotein-releasing hormone (TRH)
- Anterior pituitary
- Thyroid stimulating hormone (TSH)
- Thyroid gland
- Thyroid hormone (T3 and T4)
Laboratory Evaluation and Imaging Studies of Thyroid
Function
SSATTTT
- Serum T3
- Serum T4
- Anti-thyroid antibodies
- Thyroid stimulating hormone
- thyroid stimulating immunoglobulins
- thyroid uptake and scan
- thyroid ultrasound
This disease of the thyroid gland is the under-production of thyroid hormones
HYPOTHYROIDISM
This disease of the thyroid gland is also known as Gland destruction
HYPOTHYROIDISM
What are the diseases associated with hypothyroidism?
- Myxoedema
- Cretinism
- ThyroidITIS
Myxoedema is also called …
Gull disease
Cretinism
Hypothyroidism or Hyperthyroidism
Hypothyroidism
Grave’s disease
Hypothyroidism or Hyperthyroidism
Hyperthyroidism
Thyrotoxicosis
Hypothyroidism or Hyperthyroidism
Hyperthyroidism
Myxoedema
Hypothyroidism or Hyperthyroidism
Hypothyroidism
Thyroiditis
Hypothyroidism or Hyperthyroidism
Hypothyroidism
HYPERTHYROIDISM is also called …
thyrotoxicosis
This disease of the thyroid gland is the over-production of thyroid hormone
Hyperthyroidism
Goiter
Hypothyroidism or hyperthyroidism
Hyperthyroidism
Neoplastic processes
Hyperthyroidism or hypothyroidism
hyperthyroidism
Dietary Iodide deficiency
Primary hypothyroidism or secondary hypothyroidism
Primary
Iodine defficiency
Primary hypothyroidism or secondary hypothyroidism
Primary
Autoimmune (Hashimoto´s Thyroiditis)
Primary hypothyroidism or secondary hypothyroidism
Primary
Drugs: amiodarone, lithium, thiocyanates, phenylbutazone,
sulfonylureas
Primary hypothyroidism or secondary hypothyroidism
Primary
Iatrogenic
Primary hypothyroidism or secondary hypothyroidism
Primary
Congenital
Primary hypothyroidism or secondary hypothyroidism
Primary
Infiltrative disorders
Primary hypothyroidism or secondary hypothyroidism
Primary
Pituitary gland destruction
Primary hypothyroidism or secondary hypothyroidism
Secondary
Isolated TSH deficiency
Primary hypothyroidism or secondary hypothyroidism
Secondary
Bexarotene(anti cancer drug) treatment
Primary hypothyroidism or secondary hypothyroidism
Secondary
Hypothalamic disorders
Primary hypothyroidism or secondary hypothyroidism
Secondary
What is the automminue disorder in HYPOthyroidism?
Hashimoto’s Thyroiditis
What are the drugs in primary hypothyroidism?
- amiodarone
- lithium
- thiocyanates
- phenylbutazone
- sulfonylureas
Ratio of congenital in Primary hypothyroidism
1 in 3000 to 4000
What is the anti cancer drug in secondary hypothyroidism?
Bexarotene treatment
What are the conditions associated with secondary hypothyroidism?
PHBIs
- Pituitary gland destruction
- Hypothalamic disorders
- Bexarotene(anti cancer drug) treatment
- Isolated TSH deficiency
Hypothyroidism appears in 3 forms:
- Myxedema (Gull disease)
- Cretinism
- Thyroiditis
It is the non pitting swelling of the skin
Myxedema
Skin becomes infiltrated by mucopolysaccharides (needed enzyme to breakdown sugar molecule chains)
Myxedema
It is the severe form of primary
hypothyroidism
MYXEDEMA COMA
This disease shows as a Puffy face
Myedema (Gull disease)
This disease shows with a sign of weight gain
Myedema (Gull disease)
This disease is the hypothyroidism developing in adults, deposition of excess mucoprotein in skin of forearm, Leg, feet
Myxedema (Gull disease)
Myxedema is when the skin becomes infiltrated by what?
infiltrated by mucopolysaccharides
Hashimoto’s disease is also called what?
chronic autoimmune thyroiditis
Most common cause of primary
hypothyroidism
Hashimoto’s disease
Associated with the enlargement of the thyroid gland (goiter)
Hashimoto’s disease
Hashimoto’s disease is associated with the enlargement of the what?
enlargement of the thyroid gland (goiter)
This disease shows a high TSH and positive TPO in laboratory results?
Hashimoto’s disease
What is the laboratory results in Hashimoto’s disease?
- High TSH
- Positive TPO (Thyroid peroxidase antibody test)
This disease is a type of hypothyroidism developing in infancy/early childhood, due
to maternal iodine deficiency
Cretinism
Cretinism is due to what?
due to maternal iodine deficiency.
This disorder is associated with an impaired skeletal development
Cretinism
This disorder is associated with an impaired CNS development
Cretinism
This is the inadequate maternal thyroid hormone prior to fetal thyroid gland formation
Cretinism
Cretinism is the inadequate maternal thyroid hormone prior to what?
prior to fetal thyroid gland formation
This disorder is associated with severe mental retardation
Cretinism
This disorder is associated with dwarfism and stunted growth
Cretinism
Refers to an excess of circulating thyroid hormone.
Hyperthyroidism
What are the signs and symptoms of hyperthyroidism?
- Tachycardia
- Tremors
It refers to the involuntary twitching
movement
Tremors
Hyperthyroidism refers to an excess of what?
excess of circulating thyroid hormone.
elevated T3 and T4
Primary hyperthyroidism or secondary hyperthyroidism
Primary
Decreased TSH
Primary hyperthyroidism or secondary hyperthyroidism
Primary
Increased FT4 and TSH
Primary hyperthyroidism or secondary hyperthyroidism
Secondary
Increased FT4 and TSH is due to what?
Due to primary lesion in the pituitary gland
What are laboratory results in primary hyperthyroidism?
- Elevated T3 and T4
- Decreased TSH
What are the laboratory results in secondary hyperthyroidism?
- Increased FT3
- Increased TSH
Grave’s disease is also called …
diffuse toxic goiter
It is also called diffuse toxic goiter
Grave’s disease
Most common cause of endogenous
hyperthyroidism and thyrotoxicosis.
Graves disease
Grave’s disease is the most common cause of what?
Most common cause of endogenous
hyperthyroidism and thyrotoxicosis
It is an autoimmune disease in which antibodies are produced that activate the TSH receptor
Grave’s dsease
Grave’s disease is an autoimmune disease in which antibodies are produced that activate the what?
activate the TSH receptor
This disease is 6x more common in women
Grave’s disease
How common is Grave’s disease in women?
6x more common
What are the clinical manifestations of Grave’s disease?
- Bulgin eyes
- Pritibial myxedema
What are the clinical manifestations of cretinism?
- Dwarfism and stunted growth
- Often deaf and mute
- Severe mental retardation
- Impaired skeletal development
- Impaired CNS development
What is the diagnostic test for Graves disease?
TSH receptor antibody test
T3 Thyrotoxicosisis also called …
Plummer’s Disease
What are the laboratory results of T3 Thyrotoxicosis?
- FT3 increased
- FT4 normal
- Low TSH
FT3 increased but FT4
normal with low TSH indicates what disease?
T3 Thyrotoxicosis or Plummer’s Disease
What are the laboratory results for T4 Thyrotoxicosis?
- T3 normal or low
- T4 increased
- low TSH
T3 normal or low but T4 increased with low TSH indicated what type of thyrotoxicosis?
T4 thyrotoxicosis
This disease is a chronic inflammatory disease (mass)
Riedel’s Thyroditis
This disease is when the thyroid turns into a woody or stony-hard mass.
Riedel’s Thyroditis
Riedel’s thyroditis is when the thyroid turns into a what?
turns into a woody or stony-hard mass
What are the 11 thyroid fnction tests?
6T SPRR
- Thyrotropin Releasing Hormone (stimulation test)
- TSH Test
- Thyroglobulin (Tg) assay
- Thyroxine Binding Globulin
- T3 UPTAKE
- Total T3, Free T3 and Free T4
- Free Thyroxine Index (FTI)
- Serum calcitonin
- Pentagastrin (Pg) Stimulation Test
- Radioactive Iodine Uptake (RAIU)
- Reverse T3 (rT3)
This measures the relationship between the TRH and TSH secretions.
TRH-Thyrotropin Releasing Hormone (stimulation test)
It is used to confirm borderline cases and euthyroid Grave’s disease
TRH-Thyrotropin Releasing Hormone (stimulation test)
TRH-Thyrotropin Releasing Hormone (stimulation test) measure the relationship between what?
between the TRH and TSH secretions.
TRH-Thyrotropin Releasing Hormone (stimulation test) is use to confirm what?
to confirm borderline cases and euthyroid Grave’s disease
It is the most important thyroid function test
TSH test
It is the best method for detecting clinically significant thyroid dysfunction.
TSH test
TSH test is the best method for detecting what?
for detecting clinically significant thyroid dysfunction.
TSH test is a clinically sensitive assay for detction of what?
fo the detection of primar tyroid disorders
It is used to measure the ability of the thyroid gland to trap
iodine.
Radioactive Iodine Uptake (RAIU)
Radioactive Iodine Uptake (RAIU) is used to measure what?
to measure the ability of the thyroid gland to trap iodine.
This is helpful in establishing the cause of hyperthyroidism.
Radioactive Iodine Uptake (RAIU)
Radioactive Iodine Uptake (RAIU) is helpful in establishing the cause of what?
the cause of hyperthyroidism
High uptake + TSH Deficiency =
Autonomous Thyroid Activity.
It is normally used as a postoperative marker of thyroid cancer.
Thyroglobulin (Tg) assay
Thyroglobulin (Tg) assay is normally used as a postoperative marker of what?
postoperative marker of thyroid cancer
Used in monitoring the course of metastatic or recurrence of thyroid cancer.
Thyroglobulin (Tg) assay
Thyroglobulin (Tg) assay is used in monitoring what?
in monitoring the course of metastatic or recurrence thyroid cancer.
Formed by the removal of one iodine from the inner ring of T4.
Reverse T3 (rT3)
It is an endproduct of T4 metabolism
Reverse T3 (rT3)
Reverse T3 (rT3) is formed by what?
by the removal of one iodine
Reverse T3 (rT3) is formed by the removal of one iodine from what?
from the inner ring of T4
Reverse T3 (rT3) is an endproduct of what?
T4 metabolism
It indirectly assesses the level of FREE T4 in blood.
Free Thyroxine Index (FTI)
It is based on the equilibrium relationship of bound T4 and FT4.
Free Thyroxine Index (FTI)
Free Thyroxine Index (FTI) indirectly assesses the level of what?
the level of FREE T4 in blood.
Free Thyroxine Index (FTI) is based on the equilibrium relationship of what?
relationship of bound T4 and FT4.
THE VALUES are used to confirm hyperthyroidism
Total T3, Free T3 and Free T4
The values in Total T3, Free T3 and Free T4 are used to confirm what?
to confirm hyperthyroidism
T3 UPTAKE is not a measure of T3 SERUM LEVEL
true or false
true
This measures the number of available binding sites of the thyroxine-binding proteins, most notably TBG.
T3 UPTAKE
It helps in the diagnosis of patient having elevated T3 and T4 levels but no correlation with the other thyroid function test, or not compatible with clinical findings.
Thyroxine Binding Globulin
Thyroxine Binding Globulin helps in the diagnosis of patient having what?
having elevated T3 and T4
levels
This leads to increased serum levels T3 and T4 , but the unbound or free form of these hormones in the blood remain unchanged.
TBG EXCESS
TBG EXCESS leads to increased serum levels T3 and T4 , but the what form of these hormones in the blood remain unchanged?
unbound or free form
TBG EXCESS leads to increased serum levels T3 and T4 , but the what form of these hormones in the blood remain unchanged?
unbound or free form
It is a tumor marker for detecting residual thyroid metastasis in MEDULLARY THYROID CARCINOMA (MTC)
Serum calcitonin
Serum calcitonin is a tumor marker for detecting what?
for detecting residual thyroid metastasis
Serum calcitonin is a tumor marker for detecting residual thyroid metastasis in what?
residual thyroid metastasis in
MEDULLARY THYROID CARCINOMA (MTC)
It shoud be measured before and 6 months after surgery.
Serum calcitonin
Serum calcitonin shoud be measured how long after surgery?
before and 6 months after surgery.
It is used for the diagnosis of MTC
Pentagastrin (Pg) Stimulation Test
Pentagastrin (Pg) Stimulation Test is used for the diagnosis of what?
for the diagnosis of MTC