pituitary gland Flashcards
thyroid weight
10-20g
TSH is
thyrotropin
TSH is from
anterior pituitary
TSH does
drives production, storage and release from thyroid, under TRH control from hypothalamus
two active thyroid hormones
- thyroxine (T4)
- 3,5,3’ - triiodothyronine (T3)
T4 is formed in
thyroid gland
T3 is formed in
by deionisation in extra thyroidal tissues, particularly in the liver, kidney and thyroid (D1) and muscle, brain, pituitary, skin and placenta (D2)
thyroid hormones are bound to
serum proteins
- thyroxine binding globulin TBG
- transthyretin TTR
- albumin
- lypoproteins
bound thyroid hormones are
circulating storage pool
unbound hormones are
available for uptake into tissues, and determine hormones biological activity
T3 compared to T4
T3 is more active
variability in tissue distribution of receptors
presentation of thyroid disease
- may be symptomatic or asymptomatic
- range of pathological processes can lead to the same symptomatology
- diagnosis needs to consider anatomical, biochemical factors as well as time course and pathological process
euthyroid
normal function
hyperthyroidism
too much thyroid hormone
hypothyroidism
too little thyroid hormone
goitre
- may be unilateral, bilateral or diffuse
compression effects - by narrowing of the thoracic inlet or by impact on adjacent structures impacting airway, oesophagus, large vessels, nerves - usually not painful
hyperplasia of the thyroid
gland becomes enlarged - too many cells
diffuse hyperplasia - graves disease
multi nodular goitre/nodular colloid goitre - nodular areas in the thyroid becoming hyperplastic causing enlarged goitre
neoplasia of the thyroid
- ademonas - benign, follicular, hurthle cell, other
- carcinomas (malignant) - papillary, follicular, anapaestic, medullary
inflammatory thyroiditis
- Hashimoto - autoimmune
- lymphocytic
- granulomatous
