Endocrinology

Question 1

When does development of thyroid gland begin

Answer 1

3 weeks gestation

Question 2

What layer does the thyroid gland form from

Answer 2

Endoderm

Question 3

When does TSH production begin

Answer 3

Around 12 weeks

Question 4

Where are TRH and TSH produced?

Answer 4

TRH- hypothalamus; TSH- anterior pituitary

Question 5

Pendred syndrome

Answer 5

Autosomal recessive organification defect with congenital, eighth nerve abnormalities, leading to deafness, goiter during childhood, diagnosis by positive percholate discharge test with rapid loss of radioactive iodine from thyroid gland

Question 6

Used of what medication in first trimester associated with cutis aplasia, choanal atresia, gastrointestinal defects

Answer 6

Methimazole (preferred agent after first trimester)

Question 7

Use in first trimester associated with preauricular sinus or fistula, urinary tract anomalies, associated with low fetal birthweight

Answer 7

Propylthiouracil (still preferred during first trimester)

Question 8

Preferred first agent for neonatal hyper thyroidism and it’s mechanism of action

Answer 8

Methimazole, inhibits thyroid peroxidase, which decreases thyroid hormone synthesis

Question 9

Mechanism of action of PTU, and why it’s no longer the preferred agent

Answer 9

Inhibits thyroid peroxidase and blocks peripheral conversion of T4 to more active T3, no longer preferred agent due to potential for liver failure

Question 10

Where are the adrenal cortex and medulla derived from?

Answer 10

The adrenal cortex is derived from mesoderm, and the adrenal medulla is derived from Neuro ectodermal cells of the Neural crust

Question 11

Role of the fetal adrenal gland

Answer 11

Plays an important role in fetal adrenal steroidogenesis, and leads to the production of DHEA sulfate, which is then converted to DHEA in the placenta, and serves as a precursor for placental estrogen production

Question 12

Function of cortisol

Answer 12

1. Induces gluconeogenesis and antagonizes insulin and muscle and fat tissue, both leading to increase serum glucose levels
2. Increases lipolysis
3. Increases calcium and phosphate release from bone
4. Critical for vascular responses to catecholamines
5. Decreases inflammation and suppresses immune system.
6. Inhibits ADH increases gastric acid secretion increases production of red blood cells.

Question 13

Laboratory findings in the classic form of congenital adrenal hyperplasia

Answer 13

Low Na, high K, low glucose, high 17-OH P, high androgens

Question 14

Which two mutations in hyperinsulinemic hypoglycemia do not respond to diazoxide ?

Answer 14

ABCC8 and KCNJ11, which both abolish the function of the Katp channel and are therefore unresponsive to diazoxide, a Katp channel agonist

Question 15

Most common cause of adrenal insufficiency in the newborn

Answer 15

Mutations of the 21 hydroxylase gene, CYP 21

Question 16

How do you diagnose Pendred syndrome?

Answer 16

diagnosis by positive percholate discharge test with rapid loss of radioactive iodine from thyroid gland