Podcast
Questions and Answers
What is the primary function of the thyroid gland?
What is the primary function of the thyroid gland?
- Filtering blood
- Regulating thyroid hormone production (correct)
- Regulating blood pressure
- Producing insulin
Match the following components of the thyroid gland with their functions:
Match the following components of the thyroid gland with their functions:
Follicular cells = Synthesize and secrete thyroglobulin Parafollicular cells = Secrete calcitonin Thyroid hormones = Increase metabolic rate Iodine transport = Active transport into thyroid follicles
A substance called ____ is contained within the follicles. It is the main storage for ______ hormones and thyroid hormone ______.
A substance called ____ is contained within the follicles. It is the main storage for ______ hormones and thyroid hormone ______.
A substance called colloid is contained within the follicles. It is the main storage for thyroid hormones and thyroid hormone substrates.
Colloid is rich in thyroglobulin (a glycoprotein)
Colloid is rich in thyroglobulin (a glycoprotein)
What are the cells that are outside the follicles, which are responsible for secreting calcitonin?
What are the cells that are outside the follicles, which are responsible for secreting calcitonin?
What are the two precursors involved in thyroid synthesis?
What are the two precursors involved in thyroid synthesis?
Tyrosine is a part of a large protein called thyroglobulin.
Tyrosine is a part of a large protein called thyroglobulin.
More specifically, thyroglobulin is produced in the RER of _____ in the thyroid follicles.
More specifically, thyroglobulin is produced in the RER of _____ in the thyroid follicles.
What form of iodine is primarily absorbed in the diet?
What form of iodine is primarily absorbed in the diet?
Which of the following mechanisms drives the active uptake of iodide by follicular cells?
Which of the following mechanisms drives the active uptake of iodide by follicular cells?
What role does Na+-K+-ATPase play in iodide uptake?
What role does Na+-K+-ATPase play in iodide uptake?
Which of the following dietary forms of iodine is least likely to be absorbed directly?
Which of the following dietary forms of iodine is least likely to be absorbed directly?
Which of the following statements about iodide is true?
Which of the following statements about iodide is true?
What enzyme in the thyroid follicular lumen will facilitate the synthesis of thyroid hormones?
What enzyme in the thyroid follicular lumen will facilitate the synthesis of thyroid hormones?
What are the three main functions of thyroid peroxidase?
What are the three main functions of thyroid peroxidase?
Describe what occurs in oxidization (thyroid synthesis)
Describe what occurs in oxidization (thyroid synthesis)
What occurs during organification (of thyroid hormone synthesis)
What occurs during organification (of thyroid hormone synthesis)
Describe what occurs in coupling (aka fusion) of the iodinated tyrosines
Describe what occurs in coupling (aka fusion) of the iodinated tyrosines
1 MIT + 1 DIT =
1 MIT + 1 DIT =
1 DIT + 1 DIT =
1 DIT + 1 DIT =
How is the thyroid gland regulated?
How is the thyroid gland regulated?
What influences the regulation of thyroid hormones?
What influences the regulation of thyroid hormones?
Large amounts of triiodothyronine (T3) are produced
Large amounts of triiodothyronine (T3) are produced
A majority of thyroid hormones are transported in plasma by transporter proteins. What are these three transporter proteins?
A majority of thyroid hormones are transported in plasma by transporter proteins. What are these three transporter proteins?
What is primarily overproduced in feline hyperthyroidism?
What is primarily overproduced in feline hyperthyroidism?
What is the most common underlying cause of feline hyperthyroidism?
What is the most common underlying cause of feline hyperthyroidism?
How would you classify feline hyperthyroidism?
How would you classify feline hyperthyroidism?
Which of the following best describes thyrotoxicosis in the context of feline hyperthyroidism?
Which of the following best describes thyrotoxicosis in the context of feline hyperthyroidism?
Why is T4 preferred over T3 for initial screening of feline hyperthyroidism?
Why is T4 preferred over T3 for initial screening of feline hyperthyroidism?
What role do deiodinases play in the metabolism of thyroid hormones in cats?
What role do deiodinases play in the metabolism of thyroid hormones in cats?
What is a significant reason for the lack of diiodinase in the thyroid of cats?
What is a significant reason for the lack of diiodinase in the thyroid of cats?
What distinguishes the thyroid hormone production in cats from that in other animals?
What distinguishes the thyroid hormone production in cats from that in other animals?
Which hormone's level is primarily affected in feline hyperthyroidism?
Which hormone's level is primarily affected in feline hyperthyroidism?
List the general homeostatic actions of thyroid hormones
List the general homeostatic actions of thyroid hormones
What is the primary effect of increased thyroid hormones on cellular metabolism?
What is the primary effect of increased thyroid hormones on cellular metabolism?
Which thyroid receptors does T3 bind to in target cells to regulate gene expression?
Which thyroid receptors does T3 bind to in target cells to regulate gene expression?
Which statement about the primary factors for control of metabolism is correct?
Which statement about the primary factors for control of metabolism is correct?
In which physiological context does T3's influence lead to protein production?
In which physiological context does T3's influence lead to protein production?
Due to the increase in BMR rate of cells, what metabolisms will it alter?
Due to the increase in BMR rate of cells, what metabolisms will it alter?
What is the molecular action of thyroid hormones on the GI tract?
What is the molecular action of thyroid hormones on the GI tract?
What is the effect of thyroid hormones on renal blood flow?
What is the effect of thyroid hormones on renal blood flow?
What happens to the number of aquaporins in the collecting duct when thyroid hormones are present?
What happens to the number of aquaporins in the collecting duct when thyroid hormones are present?
How do thyroid hormones influence solute excretion in the kidneys?
How do thyroid hormones influence solute excretion in the kidneys?
Which of the following mechanisms is primarily affected by thyroid hormones in the kidneys?
Which of the following mechanisms is primarily affected by thyroid hormones in the kidneys?
What effect do thyroid hormones have on the overall glomerular filtration rate (GFR)?
What effect do thyroid hormones have on the overall glomerular filtration rate (GFR)?
What are the two physiological concepts we must consider when we are measuring thyroid hormones?
What are the two physiological concepts we must consider when we are measuring thyroid hormones?
What are the common clinical signs of hyperthyroidism?
What are the common clinical signs of hyperthyroidism?
What is the etiology behind feline hyperthyroidism?
What is the etiology behind feline hyperthyroidism?
What diagnostics can you use to diagnose a feline with hyperthyroidism?
What diagnostics can you use to diagnose a feline with hyperthyroidism?
What are the four treatment options for feline hyperthyroidism?
What are the four treatment options for feline hyperthyroidism?
How does methimazole affect thyroid physiology?
How does methimazole affect thyroid physiology?
What is a direct consequence of decreased thyroid hormone levels in canines?
What is a direct consequence of decreased thyroid hormone levels in canines?
Which of the following best describes how decreased thyroid hormone levels affect cholesterol?
Which of the following best describes how decreased thyroid hormone levels affect cholesterol?
How does hypothyroidism affect hepatic function in canines?
How does hypothyroidism affect hepatic function in canines?
Which physiological change occurs in hair follicles as a result of decreased thyroid hormones?
Which physiological change occurs in hair follicles as a result of decreased thyroid hormones?
What role do thyroid hormones primarily play in cholesterol metabolism?
What role do thyroid hormones primarily play in cholesterol metabolism?
What is the treatment for dogs with hypothyroidism?
What is the treatment for dogs with hypothyroidism?
Flashcards
Iodide form
Iodide form
Ionic form of Iodine, absorbed in the diet.
Iodine source
Iodine source
Dietary salts of iodide (e.g., sodium iodide).
Iodine (I2) form
Iodine (I2) form
Elemental form, rare in nature.
Na+/I- symporter
Na+/I- symporter
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Thyroid cell uptake
Thyroid cell uptake
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Iodino (I2)
Iodino (I2)
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Iodide (I-)
Iodide (I-)
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Absorption de Iodide
Absorption de Iodide
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Active Transporte de Iodide
Active Transporte de Iodide
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Elemental Iodine (I2)
Elemental Iodine (I2)
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Sodium/Iodide Symporter
Sodium/Iodide Symporter
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Why is Iodide important?
Why is Iodide important?
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Feline Hyperthyroidism
Feline Hyperthyroidism
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Thyrotoxicosis
Thyrotoxicosis
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Toxic Nodular Goiter
Toxic Nodular Goiter
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Functional Adenoma
Functional Adenoma
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Benign Condition
Benign Condition
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T4 to T3 Conversion
T4 to T3 Conversion
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Peripheral T3 Production
Peripheral T3 Production
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Why Measure T4?
Why Measure T4?
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Deiodinases
Deiodinases
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Feline Thyroid Differences
Feline Thyroid Differences
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Thyroid Hormone Action
Thyroid Hormone Action
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Basal Metabolic Rate (BMR)
Basal Metabolic Rate (BMR)
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Thyroid Hormone & BMR
Thyroid Hormone & BMR
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T3's Role in Metabolism
T3's Role in Metabolism
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Energy Expenditure
Energy Expenditure
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Thyroid hormone's renal effect
Thyroid hormone's renal effect
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Increased renal blood flow
Increased renal blood flow
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Decreased aquaporins in CD
Decreased aquaporins in CD
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Solute excretion
Solute excretion
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Increased solute excretion: Why?
Increased solute excretion: Why?
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Canine Hypothyroidism
Canine Hypothyroidism
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Thyroid Hormone's Effect on Hair
Thyroid Hormone's Effect on Hair
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Hypothyroidism and Cholesterol
Hypothyroidism and Cholesterol
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Hypothyroidism's Impact on Solute Excretion
Hypothyroidism's Impact on Solute Excretion
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Study Notes
Thyroid Tissue Structure
- Composed of numerous sac-like structures known as thyroid follicles.
- Thyroid follicles vary in size and play a crucial role in hormone production.
- Follicular cells are organized in a circular arrangement within the follicles.
Regulation of Hormones
- The thyroid gland controls the production of thyroid hormones through the secretion of Thyroid Stimulating Hormone (TSH).
- TSH plays a significant role in stimulating the activity of follicular cells.
Thyroid Hormones
- Thyroid hormones, specifically T3 (triiodothyronine) and T4 (thyroxine), are produced from the amino acid tyrosine.
- Both T3 and T4 are hydrophobic, allowing them to easily pass through cell membranes.
- Thyroid hormones exert their effects by binding to nuclear receptors, influencing gene expression and metabolic activity.
Thyroid Follicles and Hormone Storage
- Thyroid follicles are filled with colloid, serving as the primary storage site for thyroid hormones.
- Colloid contains thyroglobulin, a protein component that includes the amino acid tyrosine.
Thyroid Hormone Synthesis
- Thyroglobulin is synthesized within follicular cells and secreted into colloid for hormone production.
- Iodine is absorbed from the diet by follicular cells and actively transported into thyroid follicle cells.
- Iodide is trapped within these follicular cells through active transport mechanisms.
- The conversion of colloid to active thyroxine occurs within follicular cells, leading to increased metabolic rate, thermogenesis, and gluconeogenesis.
Parafollicular Cells (C-cells)
- Parafollicular cells are located outside thyroid follicles, are large, pale, and round in appearance.
- They secrete calcitonin in response to elevated plasma calcium levels.
- Calcitonin functions to reduce blood calcium levels by decreasing osteoclast activity and increasing renal calcium excretion.
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Description
Explore the intricate structure of thyroid tissue, including the essential thyroid follicles and their role in hormone production. Learn about the regulation of thyroid hormones, including T3 and T4, and their impact on metabolic activity.