major endocrine glands

Question 1

pituitary gland

Answer 1

lies in the hypophyseal fossa of the sella turcica of the sphenoid bone
attached to the hypothalamus by a stalk called the infundibulum

Question 2

thyroid gland

Answer 2

located anteriorly in the neck at the level of C5-T1
lies anterolateral to the larynx and trachea
isthmus lies anterior to the 2nd-3rd tracheal rings and unites the 2 lobes of the thyroid gland

Question 3

parathyroid gland

Answer 3

the chief or principal cell secrete pth

the oxyphil cells, functions not well known but may secrete PTH in cancer of parathyroid gland

Question 4

chromaffin cells

Answer 4

secrete adrenaline and noradrenaline

Question 5

HPA axis

Answer 5

hypothalamus produces corticotropin releasing hormone
CRH acts on the anterior pituitary causing it to produce and release adrenocortitropic hormone
ACTH acts on the zona fasiculata of the adrenal gland causing it to produce and release cortisol

Question 6

zona glomerulosa

Answer 6

produces aldosterone-a mineralocorticoid which acts on the kidney to influence sodium reabsorption and potassium excretion in order to control blood pressure

Question 7

zona fasiculata

Answer 7

produces cortisol-a glucocorticoid which acts to increase gluconeogenesis

Question 8

zona reticularis

Answer 8

produces androgens which can be converted by the gonads to sex hormones

Question 9

Addisons disease

Answer 9

complete lack of cortisol 
primary adrenal failure 
blood results:
-low cortisol 
-high potassium

Question 10

how is hyperpigmentation caused in Addisons disease

Answer 10

ACTH is synthesised by cleaving a precursor complex called pro-opiomelanocortin. In primary adrenal failure the feedback loop will stimulate production of CRH and ACTH. A metabolite of the synthesis of ACTH from pomc is melanocyte stimulating hormone which has many variants but causes hyperpigmentation

Question 11

Cushing’s syndrome

Answer 11

excess cortisol
can be caused by excessive use of steroids
NB: Cushing’s disease is a specific cause of bushings syndrome-wherein a tumour of the pituitary causes excess ACTH production driving hypercortisolism
‘moon face’

Question 12

primary adrenal failure

Answer 12

no response to ACTH

Question 13

secondary adrenal failure

Answer 13

lack of ACTH stimulation of the adrenal gland

Question 14

underachieve thyroidism

Answer 14

T3 decreased
T4 decreased
TSH increased 
weight gain 
lethargy 
bradycardia 
slow reflexes

Question 15

hashimotos disease

Answer 15

hypothyroidism

Question 16

overactive thyroid

Answer 16

T3 increased 
T4 increased 
TSH decreased 
weight loss 
tachycardia 
tremor 
diarrhoea 
goitre

Question 17

graves

Answer 17

hyperthyroidism