Thyroid Flashcards
What is the active form of thyroid hormone
T3
What does the thyroid do to iodine
Concentrates and oxidises it
What is the inactive from of thyroid hormone
T4
What proteins is thyroid hormone bound to
Globulin
Albumin
Transthyretin
Which transporters only transport thyroid hormone
MCT8
MCT10
Which types of transporter can transport TH as well as other molecules
Some Organic anion transporters OATs
Some Amino acid transporters LATs
What converts T4 to T3
D1 and D2 - type 1 and 2 deiodinase
What does D1 do
Converts rT3 to T2
Converts T4 to T3
What does D2 do
Converts T4 to T3
What does D3 do
Converts T3 to T2
Converts T4 to rT3
Which type of deiodinase is found in the thyroid
D1
Which type of deiodinase is found in brown fat
D2
Which type of deiodinase is upregulates in hypothyroidism
D2
How does thyroid hormone work
Changes transcription of genes by binding to nuclear receptor
How is thyroid hormone controlled locally
Regulation of thyroid hormone uptake transporters
Regulation of local deiodinase levels
Regulation of thyroid hormone receptor expression
What does the hypothalamic pituitary thyroid axis do
Regulates thyroid hormone action
What systems and processes does thyroid hormone effect
Metabolism
Cardiovascular system
Lipid and carbohydrate metabolism
Growth
Reproduction and development
CNS
Hyperthyroidism
Gland produces too much thyroid hormone
Thyrotoxicosis
Taking too much thyroid hormone supplementation
Used interchangeably w hyperthyroidism
How does hyperthyroidism affect the heart
Tachycardia
Atrial fibrillation
How does hyperthyroidism affect metabolism
Incr BMR
incr appetite
Heat intolerance
Protein and lipid degradation
Weight loss
Myopathy
Incr insulin turnover
Incr Gluconeogenesis
Decr insulin secretion
What can hyperthyroidism cause in the CNS
Nervousness
Seizures
Hyperphagia
What nail abnormality is caused by hyperthyroidism
Plummers nails
What skin sign is caused by hyperthyroidism
Pretibial myxoedema
Impacts of hyperthyroidism in the GI tract
Incr appetite
Weight loss
Incr motility
Transaminitis
Effects of hyperthyroidism on bones
Accelerated osteoclast activity
Hypercalcemia
Osteoporosis
Effects of hyperthyroidism on blood
Pernicious anaemia
B12 deficiency
Effects of hyperthyroidism on reproduction
Oligomenorrhoea
Gynecomastia
Erectile dysfunction
Is Graves’ disease more common in men or women
Women
Graves’ disease risk factors
HLA status
Infection
Stress
Female sex
Thyrotoxicosis treatment
Thionamide drugs - propylthiouracil, carbimazole
Radioactive iodine I-131
Thyroidectomy
Effects of hypothyroidism on cardiovascular system
Sinus bradycardia
Incr LDL
J waves of hypothermia on ECG
Why does hypothyroidism cause sensitivity to cold
Reduced cutaneous circulation
Effects of hypothyroidism on GI tract
Decr appetite
Constipation
Effects of hypothyroidism on nervous system, muscle, and bone
Impaired foetal brain development
Dementia
Slow relaxing reflexes
Growth retardation
Effects of hypothyroidism on kidneys and blood
Decr GFR
Mild hyponatremia
Normochromic Normocytic anaemia
Effects of hypothyroidism on endocrine/repro system
Delayed puberty
Decr libido
Erectile dysfunction
Effects of hypothyroidism on metabolism
Decr BMR
decr GLUT4 stimulation
What causes cretinism
Insufficient TSH for foetal brain
Hypothyroidism treatment
Levothyroxine
How are T4 T3 and TSH levels in hyperthyroidism
T3 and T4 high
TSH suppressed
How are T3 T4 and TSH in hypothyroidism
Low T3 and T4
High TSH
