Endocrine Flashcards
What is the name of the eye pathology associated with Graves disease?
Exopthlamos
List the broad effects of T3/4 on the body
- Metabolic (increase metabolism)
- Sympathetic (increase)
What are the treatment options for hyperthyroidism?
- Carbimazole (inhibits thyroid peroxidase)
- Surgery to remove thyroid
- radioactive iodine to destroy thyroid
A common side effect of carbimazole aside from hypothyrodisim?
Agranulocytosis - WBC deficiency
What does a non-visible JVP usually mean?
Hypotension
What are the Adrenal cortex zones and what do they make?
GFR - Glomerulosa, Fasciculata, Reituclaris.
Salty, Sweet, Sexy.
Aldosterone, Glucocorticoids, Androgens.
What causes Cushing’s Disease?
Pituitary adenoma causing ACTH overrelease
Name 2 each of ACTH dependant and independant Cushing’s syndrome.
ACTH dependant - Cushings disease or ectopic ACTH producing tumour.
ACTH independant - adrenal adenoma, exogenous steroids.
Which test could differentiate between Cushing’s disease and an ecoptic ACTH tumour?
Dexamethasone suppression test (should shut off pituitary ACTH).
Name a primary and secondary cause of adrenal insufficiency.
Primary - Addison’s disease
Secondary - stopping long term steroids
Bronze gums are a red flag for what?
Addison’s disease
Why does Cushing’s disease cause red striae, muscle weakness and poor healing?
Striae - decreased collagen
Weakness - gluconeogenesis
Healing - immune suppression
What are the three hormones in the cortisol ladder and where are they made?
CRH - hypothalamus
ACTH - pituitary
Cortisol - adrenals
What is the must common cause of Cushing’s syndrome?
Iatrogenic - steroids.
How can Cushing’s cause HTN?
Cortisol has minor mineralocorticoid actions, so it will increase Na absorption and water retention.
What are the molecules involved in osteoclast vs osteoblast activity and how is estrogen involved? How is cortisol involved?
Osteoblasts make RANK-L which activates osteoclasts. OPG blocks RANK-L.
Estrogen ups OPG.
Cortisol inhibits osteoblast activity and promotes osteoclast activity.
Why is normal ACTH levels and huge cortisol levels abnormal?
Huge cortisol levels should cause very low ACTH levels, even if they are ‘normal’ that is still atypical.
Outline the steps in T3/4 production.
Iodine enters thyroid follicular cell.
Thyroglobulin (TG) is made is the thyroid follicular cell.
TG is exported into lumen by exocytosis.
Thyroid peroxidase iodinated tyrosine residues of the TG. Can have 3 or 4.
TGs paired.
Endocytosis of TG back into Thyroid Follicular cell.
Proteolysis to split TGs.
Release into body by MCT8 channel.
Which thyroid carrying protein has the best affinity for T3/4?
Thyroid Binding Globulin - main carrier
Does the blood have more T3 or T4?
T4 - better at travelling due to longer half life, is converted to T3 in cells because T3 is more potent.
What organelle is the site of cholesterol production and what molecule is needed to assist?
Mitochondria, needs StAR.
What are the 2 steps of steroid production?
- Cytochrome p450 turns cholesterol into pregnenolone
- Pregnenolone into progesterone by hydroxysteroid dehydrogenase
Which hormone classes form homodimers, which form heterodimers, which have cytosolic receptors and which have nucleic receptors?
T3/4 - heterodimer (has T in it, nucleus).
Steroids - homodimer, cytoplasm
Which two hormones are trophic for prolactin and which molecule inhibits prolactin?
PRF and TRH (weirdly), dopamine shuts off prolactin
What are somatotropin, somatostatin and somatomedin and where are they made?
Somatotropin is Growth Hormone
Somatostatin is inhibitory and is made in the hypothalamus.
Somatomedin are the insulin like growth factors (IGF) made from GH in liver. - does all the hard work
What is the tropic hormone for GH and what is it in balance with?
GHRH from hypothalamus, in balance with somatostatin