Thyroid Gland Flashcards
What hormones does the thyroid gland secrete?
Thyroxine (T4)
Triiodothyronine (T3)
Calcitonin
What is a goiter?
Enlarged thyroid gland that results from hypothyroidism or hyperthyroidism
What is an endemic goiter, what does it result from?
Iodine deficiency -> decrease in T3 and T4 secretion -> compensatory mechanism leads to increase TSH secretion from anterior pituitary -> results in hyperplasia and hypertrophy of thyroid gland (due to excess stimulation)
What is a toxic goiter?
No toxins are present, but is due to hyperactivity of the thyroid gland and excess amounts of t3 and t4 is present
What is hyperthyroidism a result from?
Mostly autoimmunity
What is the most common form of hyperthyroidism?
Graves
Who does Graves’ disease most commonly affect?
Young women
What are the hallmark presentations of graves?
Goiter, hyperthyroidism, exopthalmus
What is the patho of Graves’ disease?
Autoimmunity targets TSH receptors on thyroid cells
TS Antibodies mimic TSH and bind to TSH receptor -> increase in t3 t4 secretion
What is thyroidtoxicosis (thyroid storm)?
It is the clinical presentation of hyperthyroidism and results from hyperthyroidism being untreated
What does the thyroid gland regulate?
Regulates metabolism, growth and development
What occurs during thyroidtoxicosis?
Lipid and protein catabolism
Increased metb heat -> compensatory mechanisms (flushed skin, perspiration) -> compensatory mechanisms max out -> intolerance to inc heat
What are manifestations of thyroidtoxicosis?
Excitable
Irritable
Insomnia
Anxiety
What happens to the cardiovascular system during theyroidtoxicosis and why?
Increase CO and HR meet increase o2 demands for waste removal
What does the respiratory system do when thyroidtoxicosis sets in?
Hyperventilation to expel co2
What is the treatment for thyroidtoxicosis?
1 of 3 options:
Anti thyroid drugs - suppress TH production
Radioiodine therapy - administer radioactive iodine binds to thyroid gland and emits radiation locally to destroy cells
Surgery for large goiters (can lead to hypothyroidism)
What are the three levels that hypothyroidism can occur at?
Thyroid (primary)
Pituitary (secondary)
Hypothalamus (tertiary)
In hypothyroidism, what level is it most common to have issues at?
The primary level, level of the thyroid
What is the main etiology of hypothyroidism? What occurs as a result?
Mainly due to radiation and surgery for hyperfx (istrogenic)
What are problems that result from hypothyroidism? (5)
Dec body temp Dec co Dec CNS fx Weak muscle (due to dec ATP) Increased weight due to dec basal metabolic rate
Why does the thyroid gland atrophy in Hashimoto’s thyroiditis?
TSH receptors blocked and can’t be stimulated
Tx for Hashimoto’s thyroiditis?
T4 daily
But if endemic goiter - iodine to treat deficiency
Characteristics of Hashimoto’s thyroiditis?
Autoimmune destruction of gland where antibodies act as a TSH receptor antagonist
