Part 15: Endocrine & Adrenal Steroids Flashcards
most endocrine organs are regulated by hormones released by the ____ and ____ glands
hypothalamus & pituitary
when the hypothalamus receives input from the ___ and ___, hormones are released in response to the detected situation
body & environment
in most cases, hormonal responses aim at maintaining ___
homeostasis
what are 2 important roles of the hypothalamus & pituitary?
- stimulating the secretion of hormones
2. tight regulation of hormone secretion
in general, the ____ gland secretes “releasing hormones”
hypothalamus
the pituitary gland is stimulated by the ______ to secrete stimulating hormones
releasing hormones from the hypothalamus
pituitary hormones can go on to ____ glands to secrete their hormones
endocrine
what is the main role of the multi-step hormone processes?
to tightly regulate the amount of hormone secreted and available to act on target tissues
the hypothalamus hormone, CRH (corticotropin RH) caused the release of the _____ pituitary hormone
adrenocortocotropin hormone
the hypothalamus hormone, TRH (thyrotropin RH) causes the release of the _____ pituitary hormone
TSH (thyroid stimulating hormone)
the hypothalamus hormone, GnRH (gonadotropin RH) causes the release of the ___ and ____ pituitary hormones
LH and FSH
what type of stimuli triggers the hypothalamus-pituitary-adrenal (HPA) axis?
stressful
when stressful stimuli are received by the hypothalamus, ____ hormone is released
corticotropin releasing hormone (CRH)
corticotropin RH (CRH) is also known as ____
corticotropin releasing factor (CRF)
when CRH stimulates the anterior pituitary, ____ hormone is released to act on the adrenal glands to release ____
ACTH (adrenocorticotropic hormone); cortisol
cortisol in the systemic circulation acts to combat ___ stimuli
stressful
cortisol secretion is on a ___(+/-) feedback loop
negative
more cortisol secretion leads to ____ (more or less) CRH and ACTH
less
CRH is released by the ____ in response to stressful stimuli
hypothalamus
ACTH is secreted by the ____ and stimulates the ____
anterior pituitary; adrenal cortex
cortisol is synthesized in the ____ cells of the adrenal cortex
zona fasciculata
in the adrenal cortex, cortisol is made from ____
cholesterol
cortisol is highly lipophillic, so it must be transported in the blood by being bound to ___
plasma proteins
t/f the normal plasma levels of cortisol fluctuate throughout the day to help in normal body processes
t
cortisol secretion can be affected by ___, ___, ___, ___ and various disease states
sleep, deprivation, light, stress
cortisol circulates in the blood by being bound to ____ type plasma proteins
corticosteroid-binding globulin (CBG)
once cortisol reaches the target tissue, it diffuses through plasma membranes and binds to ____ receptors
intracellular steroid receptors
t/f lipophilic drugs like cortisol can pass through plasma membranes passively
t
the activated receptor-cortisol complex dimerizes and translocates to the _____ where gene regulation is modified to influence body processes
nucleus
the binding of cortisol to the glucocorticoid receptor results in the binding of ____ to regulatory regions of DNA
glucocorticoids response elements (GREs)
when cortisol binds and alters gene transcription, this leads to altered levels of ____ made by the cell
proteins
at a systems level, cortisol signalling contributes to the balance of ___ metabolism
energy
cortisol provides an important regulatory component to the ___ system
immune
what are the glucocorticoid effects of cortisol?
energy metabolism & immune function
what are the mineralocorticoid effects of cortisol?
release of aldosterone by the adrenal gland, which is a potent agonist of mineralocorticoid receptors
the mineralocorticoid receptor is also known as the ____ receptor
aldosterone
what is Addison’s disease?
condition where the adrenal cortex does not produce sufficient cortisol or aldosterone
what is part of the treatment for Addison’s disease?
hormone supplementation
what is Cushing’s syndrome?
condition where levels of cortisol are chronically elevated, causing many systemic problems
what is the treatment for Cushing’s disease?
typically surgical removal of the adrenal glands and then hormone replacement
t/f Addison’s disease is an autoimmune disease
t
what are some of the symptoms of Addison’s disease?
muscle weakness, fatigue, weight loss, hypotension, and inability to initiate a stress response, which can cause a patient to go into shock if they experience acute stress
how can Addison’s disease cause electrolyte imbalances?
adrenal insufficiency results in reduced levels of other adrenal hormones like aldosterone, which impacts electrolyte excretion / absorption in the kidneys
treatment of Addison’s disease involves replacing adrenal hormones with ____ hormones
exogenous
what is the difference between cushing’s syndrome and cushing’s disease?
in cushing’s disease the excess cortisol is caused by an ACTH-producing pituitary tumour
t/f pituitary tumours that produce ACTH are not regulated by negative feedback
t
t/f cushing’s syndrome can occur when a tumour in the adrenal gland causes abnormally high levels of cortisol
t
some chronic diseases, like ___ and ___ may cause higher cortisol levels, resulting in Cushing’s like effects
depression; other endocrine disorders
t/f if the pituitary or adrenal glands need to be removed due to cushing’s, patients will require hormone replacement
t
t/f patients who have their pituitary and/or adrenal gland removed often present as of the have Addison’s disease
t
t/f hormone replacement for Addison’s or Cushing’s where the adrenal glands, both glucocorticoid and mineralocorticoid effects need to be replaced
t
which has greater potency at the mineralocorticoid receptor, cortisol or aldosterone?
aldosterone
t/f a decrease in aldosterone will cause a decrease in mineralocorticoid activity
t
if more mineralocorticoid activity is needed, why is it not the best idea to just increase the dosing of hydrocortisone?
because this also increases glucocorticoid activity
which corticosteroid has high mineralocorticoid activity?
fludrocortisone
t/f the high mineralocorticoid activity of fludrocortisone can replace the actions of aldosterone and facillitate more fluid & electrolyete retention
t
t/f fludrocortisone is so potent that it only requires small amount of effect
t
t/f hormone secretion & regulation are critical to maintain overall health
t
t/f disruptions in one endocrine systems can cause effects in other systems
t
t/f many presenting features of endocrine disorders overlap
t
when presenting factors of endocrine disorders overlap, what can be done to determine the pathway responsible?
blood tests
what is the focus of treatment for endocrine disorders?
replacing or reducing hormones to get to a normal level
