[IEMR12]Thyroid Flashcards
Hyperthyroxinemia: thyroxine levels, T3RU, and FTI?
High, High and Very High
Where do the parathyroid gland embed themselves after they migrate from pharyngeal pouches 3 and 4?
thyroid gland
Elevated Thyroid Binding Globulin: Thyroxine, T3RU and FTI?
High, Low, Normal
Does your body prefer to synthesize T4 or T3?
T4
How does the second messenger cAMP affect the synthesis of thyroid hormone?
The increase in cAMP increases the synthesis of thyroid hormone
Normal RIU and elevated thyroid activity?
iodine excess
hypothyroidism
What is the Wolf-Chaikoff effect?
If you provide more than a reasonable amount of iodine to restore normal thyroid function, it could actually inhibit thyroid function
What enzyme linked the tyrosine molecules to form the thyroid hormones?
thyroid peroxidase
What type of test assist in establishing an autoimmune thyroid disease?(3 points)
TSHR-Ab(LATS), antimicrosomal or anti-TG antibodies
How does T4 interacting with hormones in the pituitary gland affect T3 production?
It increases T3 production by stimulating the conversion of T4 into T3
How is RIU test conducted?
123-I is provided orally and iodine uptake is measured 24 hours later. A percentage of 33% or more is normal function but anything much higher than that is indicative of thyroid dysfunction
Low RIU and decreased thryoid activity
hypofunction
What thyroid hormone is the most biologically active?
T3
What nerve transverse the lateral borders of the thyroid gland?
recurrent laryngeal nerve
Normal RIU and decreased thyroid activity?
iodine deficiency
If thyroid hormone is deficient during prenatal and postnatal periods, how does this affect the development of the CNS? This makes the child predisposed to what condition?(2 points)
It has an adverse effect on the Central Nervous System. The child can become mentally retarded. Moreover, postnatally, the child can have growth retardation
What happens if a thyroid follicle is destroyed due to an infection or some other pathological condition?
The person would temporarily become hyperthyroid due to the sudden release of a large amount of thyroid hormones stored in the colloid in the follicle. The person would then become hypothyroid is the problem persist.
The thyroid gland travels from the foramen cecum using what embryological anatomical path?
thyroglossal duct
What is the pro hormone, T4 or T3?
T4
High RIU and normal thyroid activity?
iodine deficiency
How do small changes changes in T4 affect the relative concentrations of TSH levels?
It causes large changes in TSH levels
What is the normal range for serum thyroglobulin levels?
Less than 40 ng/mL
The neural crest derivatives from the ultimobranchial body give rise to what medullary cells in the thyroid? What hormone do they produce?
They give rise to medullary C cells that produce calcitonin
Why does thyroid hormone cause thyrotoxicosis?
The thyroid increases heart rate and contractility leading to severe overstimulation of the heart
What is you assessment: High RIU and elevated thyroid activity?
hyperfunction
What is the normal range for T4 in the plasma?
5 to 12 μg/dL
High RIU and decreased thyroid activity?
severe iodine deficiency
Is reverse T3 (rT3) biologically active?
NO!
Thyroid hormone is necessary for what general metabolic functions in the body?(3 points)
basal metabolic rate, thermogenesis and intermediary metabolism
How does estrogen affect the amount of circulating thryoxine in woman?
It raises the circulating thyroxine levels in woman
Hyperthyroidism
When considering the development of the thyroid gland, it travels from what anatomical location?
foramen cecum
What is the normal range for T3 in the plasma?
80-200 ng/dL
Does a man compared to a woman have a larger or a smaller amount of circulating thyroxine?
They have a smaller amount of circulating thyroxine
When T4 is in the cell, how does the cell dictate its utilization of T4?
If T3 is needed, T4 is converted to T3 and it interacts with receptors in the nucleus or receptors in the mitochondria
Low RIU and normal thyroid activity?
iodine excess
Where is the location of thyroid peroxidase?
The inner membrane
Decreased Thyroid Binding Globulin: Thyroxine, T3RU and FTI?
Low, High, Normal
The parathyroid migrate from what pharyngeal pouches?
3 and 4
Low RIU and elevated thyroid activity?
servere iodine excess
How do the levels of thyroid binding globuin change during pregnancy?
It increases as the weeks of pregnancy go up
What drug is provided as a substitute in the treatment of hypothyroidism?
levothyronine
What substances are provided to conduct an imaging test in an effort to assess the thyroid function?**(2 points) **How are they administered?
Radioactive Iodine or Technetrium Pertechnetate. They’re administered via IV.
Why are basal levels for thyroid hormone not necessary for normal physiological function in the body?
The opposite is true. Basal level of thyroid hormone is essential for normal function.
What is the most sensitive test when it comes to measuring thyroid function?
TSH plasma levels
The transport of iodine into the cell depends on what?
It is secondary active transport dependent on Sodium Potassium ATPase
When does thyroid hormone synthesis begin?(gestation)
Around 11 weeks gestation
Normal: Thyroxine, T3RU and FTI?
Normal, normal and normal
Hypothyroxinemia: Thyroxine, T3RU and FTI?
Low, Low and very low
normal RIU and normal thyroid activity?
normal thyroid
What gland produces thyrotropin releasing hormone? How does this hormone affect the anterior pituitary gland?
the hypothalamus synthesizes thyrotropin releasing hormone which stimulates the anterior pituitary gland to synthesize and release thyroid stimulating hormone
What is the basic structure of the thyroglobulin molecules used to synthesize T3 and T4?
Two tyrosine molecules linke to each other with added iodine
Why is thyroid hormone required for normal body growth(hormonal effect)
Thyroid hormone increases GH gene expression
The main regulatory control of thyroid hormone synthesis and release fro the thyroid gland is located in what organ in the endocrine system?
The anterior pituitary gland
How do you make T4 work?
remove the iodine molecule
Why does thyroid hormone have such a long half-life?
Thyroid hormones are avidly bound to plasma proteins
