Adrenal Hormones (Lec 17) Flashcards
Corticosteroids are synthesized form what?
cholesterol
Corticosteroids are provided mostly by ___ in the plasma
LDLs
ACTH increases the number of ____ receptors
LDL
Where is cholesterol converted to pregnenolone? What is the enzyme used?
mitochondria; cholesterol desmolase
Both ___ and ___ increase the conversion of cholesterol to pregnenolone
ACTH; angiotensin II
What is the major mineralocorticoid?
aldosterone
What is secretion of mineralocorticoids controlled by?
angiotensin II and K+
What are mineralocorticoids secreted by?
zona glomerulosa
What is the major glucocorticoid?
cortisol
Glucocorticoids affects increased blood ___ concentration
glucose
What are glucocorticoids secreted by?
zona fasciculata
DHEA and estrogen are examples of what hormone?
androgenic
What are androgenic hormones secreted by?
zona reticularis
Without mineralocorticoids, potassium levels in ECF ___ markedly and sodium and chloride are ___ rapidly from the urine
rise; lost
In regards to a lack of aldosterone, total ECF and blood volume become greatly ___
reduced
Due to a lack of aldosterone, a person will develop diminished ___ ___ and progress to a shock-like state
cardiac output
Hyperkalemia and serous cardiac toxicity are a result of what?
lack of aldosterone
An increase in ECF and arterial pressure is a result of what?
excess of aldosterone
An excess of aldosterone has a small effect on plasma ___ concentration because sodium reabsorption in renal tubules is accompanied by equivalent amount of water reabsorption
sodium
Hypokalemia and muscle weakness are a result of what?
excess of aldosterone
An excess of aldosterone stimulates transport of ___ from ECF into most cells of the body
potassium
true or false?
Excess of aldosterone causes alkalosis
true
Aldosterone ___ renal tubular reabsorption of sodium and ___ potassium in the urine
increases; increases
Describe the cellular sequence of events leading to sodium reabsorption
- aldosterone diffuses readily into the interior of the tubular epithelial cells
- aldosterone combines with mineralocorticoid receptor proteins (renal tubules)
- aldosterone-receptor complex diffuses into nucleus
- RNA transcription is induced
- sodium-potassium ATPase pump proteins are among those formed as a result of this induction
- epithelial sodium channel is also formed
What type of cells are associated with aldosterone?
principal cells
What enzyme is used in angiotensin -> angiotensin II
ACE
Is the relationship between aldosterone and angiotensin II direct or indirect?
direct
Aldosterone secretion is almost entirely independent of the regulation of ___ secretion
cortisol
Increased ___ ion concentration greatly increases aldosterone secretion
postassium
Increased angiotensin II has what effect on aldosterone secretion?
increases it
___ is necessary for aldosterone secretion but has little effect in controlling rate of secretion?
ACTH
The following are functions of what?
stimulates gluconeogenesis, increases enzymes to convert AA to glucose, mobilizes amino acids from extra hepatic tissues, decreases glucose utilization by cells, may lead to adrenal diabetes, resists stress and inflammation, causes resolution to inflammation
glucocorticoids
ex: cortisol
What disease is associated with hypoadrenalism?
Addison’s Disease
Primary Addison’s disease is due to injury to what?
adrenal cortex
Secondary Addison’s disease is due to impaired function of what?
pituitary gland
Disturbances in Addison’s disease could be caused by deficiencies in what?
mineralcorticoids and glucocorticoids
note: melanin pigmentation also involved
The following symptoms in regards to Addison’s disease are due to a deficiency in what?
decreased ECF, hyponatremia, hyperkalemia, mild acidosis, rise in RBCs, decrease in cardiac output and blood pressure, death from shock
mineracorticoids
Name some of the symptoms of Addison’s disease associated with a deficiency in glucocorticoids
loss of ability to maintain normal blood glucose concentration, reduction in both proteins and fats, muscle weakness, stress
In regards to Addison’s disease, what may cause a disturbance in melanin pigmentation?
loss of negative feedback to pituitary, allowing increased amounts of MSH
What disease is associated with hyperadrenalism?
cushing’s disease
What are the causes of cushion’s disease?
adenomas of AP, abnormal function of hypothalamus, ectopic secretion of ACTH by tumor, adenomas of adrenal cortex, excess ACTH secretion
“Buffalo torso”, moon face, acne, hypertension, and increased blood glucose are all characteristics of what?
cushing’s disease
