Anatomy and Physiology of the Endocrine System

Question 1

What hormone does somatostatin inhibit when it is released from the hypothalamus?

Answer 1

growth hormone release from the pituitary

Question 2

Give an example of a prolactin inhibiting hormone

Answer 2

dopamine, inhibits PRL secretion from the pituitary

Question 3

What are some characteristics of hypothalamic releasing hormones?

Answer 3

pulsatile secretion, act on specific membrane receptors, transduce signals via second messengers, stimulate release of pituitary hormones, induce hyperplasia and hypertrophy of target cells, regulates its own receptor

Question 4

What is the other name for the posterior pituitary?

Answer 4

neurohypophysis

Question 5

What two hormones are secreted by the posterior pituitary?

Answer 5

ADH/vasopressin

oxytocin

Question 6

What seven hormones are secreted by anterior pituitary?

Answer 6

TSH, ACTH, FSH, LH, GH, prolactin, MSH

Question 7

What are ‘tropic’ hormones?

Answer 7

hormones that regulate the function of other hormones

Question 8

What cell type of the anterior pituitary produces ACTH?

Answer 8

corticotroph

Question 9

What is the most abundant cell type in the anterior pituitary?

Answer 9

somatotroph (40-50%)

Question 10

What is the least abundant cell type in the anterior pituitary?

Answer 10

thyrotroph (3-5%)

Question 11

What is the clinical effects of a lack of ACTH?

Answer 11

loss of pigmentation, hypoadrenalism

Question 12

What is the clinical effect of a lack of ADH?

Answer 12

diabetes insipidus

Question 13

What is the clinical effect of a lack of FSH?

Answer 13

infertility

Question 14

What happens in the cell when TSH binds to thyroid specific cell surface receptors?

Answer 14

stimulates adenylate cyclase to produce cAMP
this increases metabolic activity that is required to synthesise Thyroglobulin (Tg) and generate peroxide
TSH stimulates both I- uptake and iodination of tyrosine residues on Tg

Question 15

Which thyroid hormone is biologically more active?

Answer 15

T3 is more active than T4 but has a shorter half life

Question 16

What is the predominant thyroid circulating hormone?

Answer 16

T4

Question 17

What are the most common causes of hypothyroidism?

Answer 17

primary thyroid failure due to autoimmune diseases (Hashimoto thyroiditis)
idiopathic causes
ablative therapy
iodine deficiency

Question 18

What is a myxoedema coma?

Answer 18

end stage of untreated or insufficiently treated hypothyroidism

Question 19

What lab results indicate primary hypothyroidism?

Answer 19

free T4 low and TSH high

Question 20

What is euthyroid sick syndrome?

Answer 20

low T3, normal or low TSH, normal free T4

Question 21

What biochemical laboratory findings can suggest Addison’s disease?

Answer 21

low serum Na level

high serum K level

Question 22

What are some clinical features of hyperthyroidism?

Answer 22

excessive sweating, tremor, palpitations, fatigue, increased anxiety, irregular periods

Question 23

What is the most common etiology of hyperthyroidism?

Answer 23

Graves disease

Question 24

What is the most common symptom of pheochromocytoma?

Answer 24

hypertension

classical triad: pain(headache), perspiration, palpitations

Question 25

What is the cause of Cushings disease?

Answer 25

high levels of cortisol which can be caused by glucocorticoid drugs, tumours of the pituitary or adrenal gland

Question 26

What are some signs and symptoms of Cushings disease?

Answer 26

redistribution of fat onto face and trunk (‘melon on a stick’), muscle wasting, abnormal pigmentation, hyperglycaemia and hypertension

Question 27

What are some signs and symptoms of Addisons disease?

Answer 27

progressive weakness and fragility, hyperpigmentation

Question 28

How is Graves disease treated?

Answer 28

antithyroid medications, radioactive iodine or thyroidectomy

Question 29

What is used for the palliative treatment of mild hypothyroidism?

Answer 29

beta blockers

propanalol