thyroid lumps & diagnosis Flashcards
Which pharyngeal arch does the primordial thyroid originate?
Third
Which tracheal ring does the thyroid isthmus cross at?
Second ring.
When a patient develops a thyroglossal cyst, what would happen when they stick their tongue out?
The cyst will move up and down due to being connected to the back of the tongue.
Where do the 2 superior thyroid arteries enter the thyroid gland?
Into the apex of the upper lobe on each side.
Where does the inferior thyroid artery enter the thyroid gland?
Obliquely towards the bottom - not right at the bottom of the gland.
What are the 3 sets of thyroid veins?
- Superior - comes off the upper pole.
- Inferior - comes off lower and central pole.
- Middle - comes off laterally.
Which cranial nerve supplies the thyroid gland and runs down in the carotid sheath?
Vagus Nerve - turns into recurrent laryngeal nerve.
Which hormone is produced by para-follicular cells?
Calcitonin
What would be classed as the counter hormone for calcitonin?
Parathyroid Hormone (PTH)
As calcium levels increase, what would happen to levels of PTH and calcitonin?
PTH would decrease and calcitonin would increase.
Which 2 hormones do follicular cells produce?
T3 (triodothyronine)
T4 (tetraiodothyronine/thyroxine)
Out of T3 and T4, which is the active hormone and which is the pre-hormone?
T3 = active
T4 = pre-hormone
allows for tight control of T3 levels
Which hormone can be used as a marker for tumour of C cells?
Calcitonin
The Synthesis of Thyroid Hormones:
- Plasma Iodide
- Trapping of Iodide
- Oxidation of Iodide
- Iodination of tyrosine in thyroid gland to form MIT and DIT.
- Coupling to form T4 and T3.
- Storage in the thyroid gland.
- Release of T4 and T3 in the blood.
- Peripheral conversion of T4 to T3.
- Deiodination.
