clinical biochem - thyroids

Question 1

what is the histology of the thyroid

Answer 1

spherical sacs - follicles

follicular cells

parafollicular cells

Question 2

what do follicular cells do

Answer 2

produce thyroid hormones

Question 3

what are the examples of thyroid hormones

Answer 3

thyroxine - T4

Tri-iodothyronine - T3

Question 4

what are the 8 stages of thyroid synthesis and release

Answer 4

1. Trapping of iodine
2. Synthesis of thyroglobin
3. Oxidation of iodide
4. Iodination of tyrosine
5. Coupling
6. Pinocytosis of colloid
7. Secretion of thyroid hormones
8. Transport in the blood

Question 5

what are the advantages of thyroxin binding global

Answer 5

decease in renal excretion

increase in solubility

Question 6

what are the limitations of thyroxin binding globin

Answer 6

unbound t3 and t4

bound receptors trigger negative feedback

Question 7

what is 3 functions of the thyroid hormones

Answer 7

bone growth

grown and differentiation of neuronal cells

chloesterol synthesis and metabolism

Question 8

what increases when there is a decrease in thyroid hormones

Answer 8

↑ Plasma Cholesterol
↑ Creatine Kinase
↑ Creatinine
↑ Thyroid binding globulin

Question 9

what increases when there is a rise in thyroid hormones

Answer 9

↑ Metabolic rate
↑ Plasma Calcium
↑ Sex hormone binding globulin ↑ Angiotensin Converting Enzyme ↑ Elevated Liver Enzymes (GGT)

Question 10

what parts controls t3 and t4 secretion

Answer 10

1. hypothalamus
2. anterior pituitary
3. thyroid gland 1

Question 11

what is the most thyroid disorder

Answer 11

hyperthyroidism

Question 12

what causes hyperthyroidism

Answer 12

increased thyroid hormone release

overactive thyroid

Question 13

what is graves disease

Answer 13

autoimmune

hyperthyroidism

Question 14

what causes graves disease

Answer 14

antibodies to TSH receptor

stimulates T3 andT4 release -> hyperthyroidism

Question 15

what are symptoms of graves disease

Answer 15

bulging eyes

goitre- enlargement of the thyroid gland

Question 16

what are symptoms of hyperthyroidism

Answer 16

increased irritability

increased sweating

heat intolerance

loss weight

Question 17

what is the diagnosis of graves disease

Answer 17

low TSH, high T4

increased iodine uptake

Question 18

what is the treatment and management for hyperthyroidism

Answer 18

• anti-thyroid drugs
• radioactive iodine
• subtotal thyroidectomy

Question 19

what does primary hyperthyroidism affect

Answer 19

the thyroid directly

Question 20

what does secondary hyperthyroidism affect

Answer 20

the anterior pituitary or hypothalamus

Question 21

what is hashimotos thyroiditis

Answer 21

autoimmune destruction of the thyroid gland

Question 22

what congenital abnormalities

Answer 22

developmental defeats

metabolic defects

ectopic organ development

Question 23

what are the clinical features of hypothyroidism

Answer 23

myxoedema

(swelling of skin)

Question 24

what are the main biomarkers of hyperthyroidism

Answer 24

Thyroid stimulating hormone(TSH)

T4

Question 25

what happens to TSH sonf TV in hypothyroidism

Answer 25

↑TSH

↓T4