Pituitary clinical Flashcards
(25 cards)
Outline hormone hierarchy in HPA axis for thyroid hormones
Hypothalamus –> thyrotropin releasing hormone, anterior pituitary –> TSH, this stimulates TSH receptors on thyroid gland to produce T4 (thyroxine) and t3 (thyroiodide). As they circulate, t4 is converted into t3 and recognised by t3 receptors on tissues in the periphery.
Effect of thyroid hormones
increase pulse, increase metabolism
How does hypothyroidism arise in periphery
rare genetic condition, got enough of thyroid hormones but lack the right receptors and hence are resistant, get symptoms of deficiency
How does hypothyroidism arise due to thyroid gland itself
Hashimoto’s most common, autoimmune disease where t cells destroy thyroid gland and get deficient in thyroid hormone
How can the pituitary gland cause hypothyroidism
If doesn’t produce TSH, thyroid gland will be inactive
How can hypothalamus cause hypothyroidism
Rare, for eg if exposed to radiation or have tumour, can’t produce thyrotropin releasing hormone
What is primary, secondary, tertiary & resistance hypothyroidism?
Primary - due to thyroid gland
Secondary - due to anterior pituitary
Tertiary - due to hypothalamus
Resistance - due to problems in the periphery
Embryological origin of anterior vs posterior pituitary
Posterior: notochord, purely neural structure
anterior: buccal cavity
Which hormones does posterior pituitary make
ADH and oxytocin
What is diaphragma selae
covers top of pituitary, only allowing pituitary stalk to exit. it separates CSF from pituitary gland itself
Name 6 hormones of anterior pituitary
prolactin, TSH, FSH, LH, growth hormone, ACTH
What are the possible consequences of having too much growth hormone/too little
Becoming giant, or if epiphyses have fused - acromegaly. Short stature or if plates have fused - deficiency
What happens if deficient in growth hormone
lose energy, exercise capacity, gain weight around the middle, lose skeletal muscle
Outline hierarchy of hormones using what’s produced in anterior pituitary and the organs it affects
ACTH - adrenals - cortisol LH/FSH - gonads - testo/estradiol GH - liver - IGF-1 PRL - breast - prolactin TSH - thyroid gland - thyroxine
Difference between pituitary tumours in terms of size, and function
functioning - too much of a specific hormone being produced
non-functioning - no excess hormone being produced
size - if less than 10mm then microadenoma, if more = macroadenoma
What is insulin tolerance test
Make individual hypoglycaemic, administer insulin - should encourage counter regulation where produce glucagon, adrenaline, cortisol, growth hormone
Do men make prolactin
yes
What is menses in men and women
men - loss of erection, women - loss of periods
How do we test for pituitary function
target hormone and pituitary hormone together
Why can one get high prolactin if have pituitary tumour
enlarged tumour, prevents dopamine travelling down stalk of pituitary and inhibiting prolactin
Pituitary tumour: secretes GH - what syndrome?
Acromegaly
Pituitary tumour: secretes ACTH - what syndrome?
Cushing’s
Pituitary tumour: secretes prolactin - what syndrome?
Galactorrea & amenorrea
Pituitary tumour: secretes TSH - what syndrome?
Thyrotoxicosis
