Thyroid Flashcards
What are the two types of cells in the parathyroid gland and what do they secrete?
Chief cells-PTH (dark staining, arranged in clumps and cords)
Oxyphill cells (scanty, pale staining)
What is Trousseau’s sign of latent tetany?
Trousseau sign of latent tetany is a medical sign observed in patients with low calcium.
Induced by placing a sphygnomanometer above systolic BP for 3 minutes.
This sign may be positive before other manifestations of hypocalcemia such as hyperreflexia and tetany, as such it is generally believed to be more sensitive (94%) than the Chvostek sign (29%) for hypocalcemia.
What is Chvostek’s sign?
Chvostek’s sign is the twitching of the facial muscles in response to tapping over the area of the facial nerve. Due to hypocalcemia.
What do parafollicular cells of the thyroid secrete?
Calcitonin
Medularry carcinoma of thyroid arise from these cells
Hurthle cells
Eosinophilic epithelial cells withh accumulation of mitochondria
Seen in Hashimoto thyroiditis
DeQuervain thyroiditis
Granulomatous thyroiditis
Viral or post viral syndrome
Hyperthyroidism
Heals with normal thyroid function
psamomma bodies
orphan Annie’s eyes nucleus
Papillary carcinoma of thyroid
congo red stain positive
Amyloid
Medulary carcinoma
(from parafollicular C cells)
apple green birefringence on polarsing microscope
Amyloid
Medulary carcinoma
(from parafollicular C cells)
what is the effect of 1,25-DHCC on calcium absorption?
PTH stimulates conversion of Vit D to 1,25-DHCC which then increases absorption of calcium from the gut.
Looser’s zones /Milkman’s lines
Partial fractures in osteomalacia
What stimulated conversion of vitamin D to its active form?
high PTH levels
low plasma ionised calcium
low phophate levels
low 1,25-DHCC
How does 1,25-DHCC affect calcium absorption and bone mineralisation?
Enhances calcium uptake from the intestines and deposition of bone mineral
