Flashcards in T3 Adrenal Hormones Deck (38)
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1
What does the medulla secrete?
epinephrine and norepinephrine
2
The medulla is functionally related to the _______ nervous system.
sympathetic
3
What does the cortex secrete?
corticosteroids
4
What are corticosteroids synthesized from?
cholesterol
5
The synthesis of corticosteroids synthesized from cholesterol is provided mainly by _______ in the plasma, mostly attached to coated pits
LDLs
6
_______ increases the number of LDL receptors.
ACTH
7
Where is cholesterol converted to pregnenolone?
mitochondria
8
Conversion of cholesterol to pregnenolone is catalyzed by what? What is significant about this step?
cholesterol desmolase; rate limiting step
9
Both ACTH and _______ increase the conversion of cholesterol to pregnenolone.
angiotensin II
10
Progesterone can be converted to what?
deoxycorticosterone, which is then converted to aldosterone. Also can be converted to cortisol
11
What is the major mineralocorticoid? What's its half-life?
aldosterone; 20 minutes
12
Hyperkalemia has what effects?
aldosterone secretion
13
What substance increases sodium reabsorption by kidney tubules?
mineralocorticoids
14
Aldosterone increase ___________ secretion by kidneys, by acting on __________ in _________.
potassium; principle cells; late distal tubules
15
Aldosterone increase ___________ secretion by kidneys, by acting on __________ in _________.
hydrogen ion; intercalated cells; late distal tubules
16
What is secretion of mineralocorticoids controlled by?
angiotensin II and K+
17
What are mineralocorticoids secreted by?
zona glomerulosa
18
What is the major glucocorticoid?
cortisol
19
What is essential in the stress response?
cortisol
20
What is cortisol secretion controlled by?
ACTH from anterior pituitary
21
What are glucocorticoids secreted from?
zona fasciclutata
22
Cortisol has a ______ feedback response to both CRH and ACTH.
negative
23
Cortisol oscillates with circadian rhythm. When is it highest? when is it lowest?
highest = before wakeing
lowest = in evening
24
What are the precursors to estrogens?
DHEA and androstenedione
25
Where is DHEA converted to testosterone?
in the testes
26
What is the outcome of a lack of aldosterone?
-total loss causes death in days
-total ECF and blood volume reduced
-diminished CO and progresses to shock-like state
-hyperkalemia and serious cardiac toxicity follow
27
What is the outcome of a excess of aldosterone?
-increase ECF and arterial pressure
-hypokalemia and muscle weakness
-causes alkalosis
-Small effect on plasma sodium concentration because sodium reabsorption in renal tubules is accompanied by equivalent amount of water reabsorption
28
What is the overall effect of aldosterone?
increases renal tubular reabsorption of sodium and increases potassium in the urine
29
What are the functions of glucocorticoids
Stimulate gluconeogenesis by:
-increase protein catabolism
-mobilizes aa
-enhances transport of aa into hepatic cells
-increase enz req to convert aa to glucose
-decrease glucose utilization by cells
-increase lipolysis
May lead to adrenal diabetes
Resists stress
Resists inflammation
Causes resolution of inflammation
Inhibits immune response
Maintains vascular response to catecholamines
30
What are catecholamines?
norepi and epi
31
What is primary Addison's disease caused by?
injury to adrenal cortex
32
What is secondary Addison's disease caused by?
impaired function of pituitary gland
33
What are some disturbances of hypoadrenalism/addisons?
Due to mineralocorticoid deficiency, due to glucocorticoid deficiency, and melanin pigmentation
34
What are symptoms of mineralocorticoid deficiency?
-decreased EC volume
-hyponatremia
-hyperkalemia
-mild acidosis
-rise in RBC concentration
-decrease in CO and BP
-metabolic acidosis
-death from shock
35
What are symptoms of glucocorticoid deficiency?
-hypoglycemia
-weight loss, nausea, vomiting
-muscle weakness
-highly susceptible to stress
-reduction in both proteins and fats leading to depression of other bodily functions
36
What are symptoms of melanin pigmentation?
-may be caused by loss of negative feedback to pituitary, allowing increased amounts of MSH
-results in uneven distribution of pigmentation, esp in thin skin areas
37
What are the causes of Cushings/hyperadrenalism
-administration of glucocorticoids
-adenomas of ant pituitary
-abnormal function of hypothalamus
-ectopoc secretion of ACTH by tumor
-adenomas of adrenal cortex
-excess ACTH secretion is cause of Cushing's
38
