Section 6 Adrenal Gland Flashcards
List the zone of the adrenal gland between the capsule and the adrenal medulla:
glomerulosa, fasciulata, and reticularis
in which layer of the adrenal gland are catecholamines produced?
adrenal medulla
in which layer of the adrenal gland are sex hormones produced?
Zona reticularis
in which layer of the adrenal gland are glucocorticoids produced?
Zona fasciculata
in which layer of the adrenal gland are aldosterone produced?
Zona glomerulosa
How many zones make up the adrenal cortex and name:
3; Zona glomerulosa, fasciulata, and reticularis
How is AI converted to AII?
by renin and ACE
The primary mineralocorticoid is:
aldosterone
What does AII stimulate?
aldosterone production
What secretes renin?
the JGA
Factors that increase renin secretion:
low pressure, low luminal sodium concentration, sympathetic nerve activity
What does high plasma K+ concentration stimulate?
aldosterone release
What structures do juxtaglomerular cells surround?
afferent and efferent arterioles and the macula densa of the distal tubule
Actions of aldosterone;
Na+ retention and K+ excretion
aldosterone + receptor affects on transcription and proteins synthesis:
new channels to add to luminal side of distal nephron, new pumps to add to interstitial fluid side facing blood supply, and proteins modulate existing channels and pumps
Net ion movement as a result of aldosterone:
K+ secreted into the lumen of distal nephron from the blood and Na secreted into the blood from the lumen
True or False? Aldosterone exerts its effects at the transcriptional level.
T
Cortisol can negatively-feedback to:
both ACTH (anterior pituitary gland) and CRH (hypothalamus)
what part of the adrenal gland is connected to mineralocorocoids, glucocorticoid, sex hormones (weak androgens)
cortex, endorcrine
True or False? The adrenal medulla releases epinephrine but not norepinephrine.
F. Releases both, some norepinephrine
What cells are neural derived cells?
chromafin cells, stain brown w/ chromium salts
Which part of the adrenal gland is like n extension of the chain ganglion?
the adrenal medulla
What types of tissue is most of the adrenal gland made of?
cortical tissue
List 2 catecholamines:
epinephrine and norepinephrine
Functions of outer zone of the adrenal cortex:
aldosterone, Na+ reabsorption, K+ loss
True or False? There is overlap between which layers produce which hormones.
T
Which zone makes up a larger part of the cortex?
zona fasiculata
What do the inner 2 zones release?
and sex hormones and glucocorticoids
Where are steroid stored?
They aren’t. They are made on demands. Activate enzymes that tun on the biosynthetic pathway for steroid production
Why is it difficult to store steroids?
cholesterol derived, lipophilic
What is a bottle neck enzyme?
stimulates pathway that leads to production and release of a hormone (check)
The only (steroid) storage hormone:
thyroid hormones (not really a steroid but is like one because of its lipophilicity
How many carbons are in steroids
27 Carbons, 4 rings, tail
What controls the adrenal cortex
anterior pituitary corticotrophs, controlled by the hypothalamus
What gets converted to testosterone and estrogen?
androstenedione (weak androgens)
Critical bottleneck step
conversion of chesterol to an intermediate in pathway
1st and major step being regulated to drive the formation of the desired hormone:
Cholesterol side chain cleavages
What controls the formation of aldosterone from cholesterol?
pituitary hormones, angiotensin, and others
Critical regulator that stimulates the enzyme in the pathway from cholesterol to aldosterone:
angiotensin
This is a protein-gestational hormone:
progesterone
Intermediates in the pathway from cholesterol to aldosterone:
pregenolone, progesterone, 11-deoxycorticosterone, corticosterone
What converts corticosterone to aldosterone?
aldosterone synthase
True or False? There is no cross-reactivity of the steroid receptors for cortisol to bind to mineralocorticoids, or mineralocortocoids to glucocorticoids receptors, etc.
F. similarity in structure of all these receptors
What kind of activity does corticosterone have?
glucocorticoid activity, try to get rid of this in the final step to aldosterone
True or False? For the most part there is specificity of the receptors.
T
True or False? Cortisol can act like a mineralocorticioid.
T. If receptors are stimulated with high enough levels of cortisol.
Property of steroids:
alter gene transcription of proteins
True or False? Aldosynthase is found in the inner 2 zones.
F.
Where are weak androgens converted?
The periphery
What comes out of the anterior pituitary corticotrophs?
ACTH to go to the periphery, hypothalamus will release CRH through the portal circulation
What does ACTH activate?
Cortisol production: cholesterol side chain cleavage in inner zones of adrenal cortex, driving reactions through hydroxylation, dehydrogenases, etc.
DHEA supplementation:
overstimulation with lipophilic steroids take a while to get out,(longer half life) potential complications with steroid toxicity, doesn’t work very well
enzyme controlling production of mineralocorticoids, glucocorticoids, and weak androgens:
CSCC
cortisol has cross-reactivity with:
mineralocorticoids
How much more cortisol is there in the blood stream than aldosterone?
10 more
Cortisol starts activating mineralocorticoids:
cortisol induced hypertension, increases Na reabsorption, increases blood pressure
What stimulates CSCC to make aldosterone?
angiotensin
What can stimulate the pathway to get to DHEA and the weak androgens?
LH
What enzyme does the kidney have that prevents cortisol induced hypertension?
11 beta hyroxyhydrogenase (11 beta HSD)
cortisol gets inactivated to:
cortisone
cortisone via ___ to cortisol.
reductase
Is cortisone active or inactive?
inactive
Why are we prescribed cortisone if it is inactive?
most tissues have reductase, the enzyme that convert it to cortisol
food that can cause hypertension:
licorice induced hypertension, pseudo mineralocorticoid hypertension
Molecular cause of licorice induced hypertension:
inhibition of 11-beta-HSD, inactivates kidney cortisol, no mineralocorticoid activity
Block inactivation of cortisol at the kidney:
lots of cortisol in the kidney left, acts like aldosterone, increase blood pressure
How do mineralocorticoids increase aldosterone production?
inc side chain cleavage induced by ang II and the only zone that has aldosterone synthase
Where is angiotensinongen synthesized?
liver
What kind of peptide is angiotensin I?
decapeptide
What kind of peptide is angiotensin II?
octapeptide
Ace inhibitors help people with:
renin induced hypertension
From where is renin secreted?
JGA
Under what conditions is renin released?
low blood pressure (arterial or JGA)
2 ways angiotensin increases blood pressure?
direct effect: vasoconstriction, indirect effect: aldosterone secretion from adrenal cortex
What sense low flow through the JGA
interrenin pressure receptors
how to increase blood pressure via cells:(rephrase)
depolarize cells in the adrenal cortex, K increase in plasma, aldosterone release, na reabsorption, loss of K+, start with high potassium, excrete more K+
What leads to the production of glucocorticoids?
cleavage of ACTH
5-20 interspersed cells in the JGA between smooth muscle and endothelial cells
renin secreting cells, sense pressure, symp nerves innervate that area as well to drive the change
Most of the binding protein of aldosterone is:
albumin
Are the Na channels on the apical or basal side of the distal tubule?
apical
True or False? Glucocorticoids affect every system in the body.
T
True or False? Glucocorticoids have a permissive affect.
T
Effect of glucocorticoids on immune functions:
depresses it, inflammatory cell, stimulates antibiotics-inflammatory cytokines
What axis are we talking about when discussing glucocorticoids?
Hypothalamis, anterior pituitary, adrenal cortex axis
True or False? Starvation is a major trigger for the release of glucocorticoids.
T. dietary, psychological, etc.
circadian rhythm in:
central hormones, especially cortisol
True or False? CRH can inhibition CRH.
T
What type of glucose are you making in starvation?
denovo glucose cortisol stimulates every gluconeogenic enzymes
amino acids for gluconeogenesis in starvation:
cortisol breaks down muscle, (greatest pool of proteins) to release amino acids to create glucose
What is the final thing to kill a starving person?
decrease muscle mass, decreasing intercostal muscle mass, die of suffocation, stomach full of fluid because of low oncotic pressure
What actions provide the substrates for gluconeogenesis?
extrahepatic actions
primary functions of cortisol:
increase gluconeogenesis in the liver and glycogen formation
Affect of cortisol on insulin:
decreases sensitivity of insulin
Action of insulin in periphery:
increases glucose uptake
Type I
destruction of beta cells in pancreas
Type II:
insulin resistant, not a receptor problem, signal transduction of insulin is messed up
How to increase glucose transport in people who are insulin resistant?
aerobic exercise, glucose uptake in peripheral skeletal muscle
Affect of glucocorticoids on brain
well being, mental acuity, pomc to ACTH, encephalins and endorphins being made
How does cortisol increase water retention?
via ADH system, affects GFR, and cardiac output as well
Cortisol in the GI system:
inhibits Ca uptake in the jejunum
What hormone can lead to the formation of both glucose and glycogen?
cortisol
What store of glucose is used by skeletal muscle in the starved state?
free fatty acids
True or False? Ganglionic transmission release hormones from the adrenal medulla.
T. essentially
What kind of response triggers hormone release from the adrenal medulla?
neuroendocrine response
norepinephrine
beta 1 stimulation ( heart, increase contractility), increase blood pressure (both systoles and diastole)
epinephrine:
peripheral vasod, some alpha, stronger B2, total drop in diastole pressure, mean pressure increases with epinephrine but not as much because diastolic isn’t going up as much. Increases epinephrine dose, override B2 dilation in the peripheral, increases epinephrine, it will eventually look like norepinephrine (B1 and alpha)
Low does epinephrine:
B2 effect (?)
True or False? All catecholamines increases blood pressure and contractility in the periphery.
F. most. (check)
Anything that increases a lipolytic pathway with be stimulated by:
HSL (in what we talk about, not only way), cleaves free fatty acids off triglycerides
