Wk 29 Flashcards
What hormones are released from the adrenal cortex?
What hormones are released from the adrenal medulla?
Cortex= Glucocorticoids (cortisol, corticosterone)
Medulla= Adrenalin and noreadrenalin
What are the 3 layers of the adrenal cortex and what hormones does each layer secrete?
Outermost layer= Zona glomerulosa (Mineralocorticoids- mainly aldosterone)
Middle= Zona fasculata (Glucocorticoids- mainly cortisol)
Inner cortex= Zona reticularis (Androgens)
What hormone does the hypothalamus release that goes to the anterior pituitary to stimulate the next hormone (related to glucocorticoid release from adrenal cortex)?
What hormone does the anterior pituitary release?
Hypothalamus releases: Corticotropin-releasing hormone (CRH)
Anterior pituitary then releases: Adrenocorticotropic hormone (ACTH)
CRH released by hypothalamus in response to what?
Stressors
Where does the synthesis of cortisol occur in the adrenal cortex?
What is cortisol made from?
Zona fasciculata
Cholesterol
How does Adrenocorticotrophic releasing hormone stimulate the adrenal gland to produce steroid hormones?
It promotes the uptake and release (from storage) of cholesterol so steroids can be synthesised
What is the major carrier of cholesterol to peripheral tissues?
LDL
Corticotrophin Releasing Hormone is released as pulsatile secretions so this stimulates Adrenocorticotrophic Hormone to also be released in pulsations…
Which time of the day has the highest pulsations?
Late night/ early morning
Is cortisol lipid or water soluble?
Lipid sol
What are the carrier proteins that transport cortisol in the blood? 2
Cortisol binding globulin or transcortin (albumin does a lil bit)
Secretion of cortisol is mainly controlled by ACTH, but secretion is also promoted by what 3 things?
Vasopressin/ ADH (increases BP)
Nitric Oxide
Some cytokines
Does cortisol promote or inhibit the release of CRH and ACTH?
Inhibits (Neg feedback loop)
What is Cushing’s Disease and does it increase or decrease ACTH and cortisol?
It is a tumor in the pituitary gland that makes ACTH so there is high cortisol and because there is neg feedback, this lowers the really high levels of ACTH so ACTH levels can be high or normal
What is Cushing’s syndrome caused by? 2 options
Adrenal tumour or Ectopic ACTH
Adrenal tumour= Lots of cortisol being produced which has neg feedback on ACTH so low ACTH (same action with steroid drugs)
Ectopic ACTH= lots of ACTH and lots of cortisol
What is Adrenal Insufficiency? 2 options
It can be either Addison’s Disease or Hypopituitarism
Addison’s disease= adrenal damage so high levels of ACTH but still low levels of cortisol
Hypopituitarism= Pituitary gland isn’t secreting ACTH properly so low ACTH and therefore low cortisol
What is an anabolic effect of cortisol? (on the liver)
What are 2 catabolic effects of cortisol? (on muscle and adipose tissue)
Anabolic on Liver: Gluconeogenesis (making blood glucose from AA and glycerol etc)
Catabolic on muscle: Protein breakdown
Catabolic on adipose: lipolysis
Is cortisol slow or fast acting? Why?
Slow because effects on transcription and translation
What is the main action of cortisol?
It is a glucocorticoid so main action is on glucose metabolism: anti-insulin effect so releases stored glucose into blood (enhances action of glucagon)
How does cortisol stimulate the urea cycle in the liver?
By gluconeogenesis in the liver
As AA are converted to glucose, lots of nitrogen is generated which needs to be cleared so urea cycle enzymes are recruited and the nitrogen enters the cycle and is converted to urea which is excreted by kidneys
How does cortisol affect the muscles?
It stimulates protein catabolism to release AAs for gluconeogenesis in the liver