Study your flashcards anywhere!
Download the official Cram app for free >
- Shuffle
Toggle OnToggle Off
- Alphabetize
Toggle OnToggle Off
- Front First
Toggle OnToggle Off
- Both Sides
Toggle OnToggle Off
- Read
Toggle OnToggle Off
How to study your flashcards.
Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key
Up/Down arrow keys: Flip the card between the front and back.down keyup key
H key: Show hint (3rd side).h key
A key: Read text to speech.a key
101 Cards in this Set
- Front
- Back
3 Functional zones of the Adrenal Cortex:
|
-Zona glomerulosa - outermost
-Zona fasciculata -Zona reticularis - innermost |
|
What does the zona glomerulosa secrete?
|
Aldosterone
|
|
What do the Zona fasciculata and reticularis secrete?
|
Cortisol and androgens
|
|
What does the adrenal medulla secrete?
|
Catecholamines
|
|
What is the first molecule that is needed for making steroid hormones in the adrenal cortex?
|
CHOLESTEROL!
|
|
How many carbons are in cholesterol?
|
27
|
|
What is needed for cholesterol to be taken up by the adrenal cortex cells into their inner mitochondrial membrane?
|
ACTH must bind its receptor and activate adenylate cyclase for cAMP increase.
|
|
So what is the step that needs cAMP increased so cholesterol is taken up into the inner mitochondrial membrane?
|
The rate limiting step
|
|
Why does cholesterol have to get into the inner mitochondrial membrane anyway?
|
Because that's where Desmolase is, which converts Cholesterol to Pregnenalone
|
|
What happens to pregnenolone?
|
It goes back into the cytosol and gets converted to either Progesterone, or 17-hydroxypregnenalone.
|
|
What enzyme acts on either pregnenolone or progesterone?
|
17-alpha hydroxylase
|
|
What are the products of 17-alpha hydroxylase?
|
Either 17-hydroxyprogesterone or 17-hydroxypregnenalone.
|
|
What is the product if 17-20 lyase acts on 17-hydroxypregnenalone?
|
DHEA - dehydroepiandrosterone
|
|
What is the product if 17 20 lyase acts on 17-hydroxyprogesterone?
|
Androstenedione
|
|
What does 17-hydroxyprogesterone become if it doesn't get turned into an androgen?
|
11-deoxycortisol, then Cortisol.
|
|
What happens to progesterone if it doesn't get acted on by 17-hydroxylase?
|
It gets converted to corticosterone and ultimately aldosterone.
|
|
What is deficiency of 21-hydroxylase called?
|
Congenital adrenal hyperplasia
|
|
Why do we care about CAH?
|
Because it's the most common genetic defect in kids.
|
|
What are the effects of 21-hydroxylase deficiency?
|
-Inability to make cortisol
-Overabundance of ACTH -Hyperplasia of the adrenals |
|
As the adrenals ramp up their conversion of cholesterol to pregnenolone via the stimulation of all that ACTH, what happens?
|
They can't make cortisol obviously, so it gets shunted into the androgen pathway
|
|
What happens to females with CAH?
|
Virilization
|
|
How do Cortisol and Corticosterone compare in terms of potency of strength?
|
Cortisol is about 2x more potent
|
|
What corticosteroid is used for inflammation and asthma?
|
Prednisone - 4X more potent than cortisol.
|
|
What is the most potent synthetic corticosteroid?
|
Dexamethasone
|
|
What is dexamethasone used for?
|
Treating CAH
|
|
What steroid hormone has the highest concentration in the plasma? What is 2nd highest?
|
DHEA - highest
Cortisol - second |
|
What are 3 forms of cortisol in the blood?
|
-CBG bound
-free -albumin bound |
|
What protein has the highest affinity for cortisol? Where is it made?
|
CBG - in the liver
|
|
What form of cortisol is biologically active?
|
Only free and unbound
|
|
What type of cortisol do we measure? Why?
|
Bound - because normally 95% of cortisol is circulating bound to CBG, it's a fairly good estimate of total levels.
|
|
What are cortisol's 2 effects on the CNS? (hypothalamus)
|
-Decreases CRH
-Increases appetite |
|
How does Cortisol affect the cardiovascular system?
|
It maintains sensitivity to vasoconstrictors by allowing epinephrine to exert its effect.
|
|
What do we call the effect Cortisol has on the CV system's sensitivity to epinephrine?
|
Permissive
|
|
How does cortisol affect the liver?
|
Increases gluconeogenesis
|
|
How does cortisol affect the lungs?
|
Causes fetal lung development
|
|
How does cortisol affect the pituitary? Kidney?
|
Pituitary - decreases ACTH
Kidney - increases the GFR |
|
How does cortisol affect bone?
|
-Increases bone resorption
-Decreases bone formation |
|
How does cortisol affect muscle?
|
-Catabolizes it
-Decreases its insulin sensitivity |
|
How does cortisol affect the immune system?
|
Suppresses it
|
|
How does cortisol affect connective tissue?
|
Decreases collagen synthesis.
|
|
What 4 effects does CORTISOL have on MUSCLE's intermediate metabolism?
|
1. Increases protein breakdown
2. Decreases protein synthesis 3. Decreases glucose utilization 4. Decreases insulin sensitivity |
|
What 3 effects does CORTISOL have on ADIPOCYTE intermediate metabolism?
|
1. Decreases glucose utilization
2. Decreases insulin sensitivity 3. Increases lipolysis |
|
What are the 2 general effects of Cortisol on intermediate metabolism?
|
1. Increased gluconeogenesis
2. Decreased glucose uptake |
|
If a patient comes into the ER and is very hypotensive and doesn't respond to an injection of the normal vasoconstrictors, what should you do?
|
Give a shot of hydrocortisone because the patient probably has adrenal insufficiency.
|
|
How long would it take to see the hydrocortisone shot take effect?
|
4-6 hours
|
|
Why do patients with adrenal insufficiency not respond to the normal vasoconstrictors?
|
Because they lack Cortisol's permissive effect of maintaining sensitivity to epinephrine.
|
|
How would you confirm adrenal insufficiency in this patient?
|
By checking their ACTH levels which would be high.
|
|
What is the gene from which Cortisol is transcribed?
|
The POMC gene
|
|
What does POMC stand for?
|
Pro-opio-melano-cortin
|
|
What allows corticotrophs to make ACTH even though the POMC gene has the capability of making Melanocyte stim hormone, y-lipotropin, b-endorphin, etc?
|
The protein product of post translational processing is determined by the enzymes in that cell; corticotrophs have the enzyme that makes ACTH.
|
|
What are the 2 enzymes that cleave the POMC gene?
|
PC1 (prohormone convertase 1)
PC2 (same but 2) |
|
What enzyme does the anterior pituitary have? Why?
|
PC1 - because this is what cleaves the ACTH product
|
|
Where is PC2 found? Why?
|
In the hypothalamus - because this is what results in MSH
|
|
What stimulates the release of ACTH from the anterior pituitary?
|
CRH from the hypothalamus.
|
|
What stimulates the hypothalamus to make CRH?
|
Stress like decreased blood sugar or hypotension.
|
|
What happens when Stress/CRH stimulate ACTH release?
|
It stimulates Cortisol secretion by the adrenal cortex.
|
|
What happens when Cortisol is released?
|
It inhibits more release of ACTH and CRH, and relieves the stress.
|
|
How fast does cortisol synthesis and secretion go up in response to stress?
|
Very fast - within minutes.
|
|
How fast do the effects of cortisol appear?
|
Not very fast - blood pressure doesn't increase for about 4-6 hours.
|
|
What type of pattern is the normal daily cortisol release?
|
Circadian
|
|
When do cortisol levels rise and peak?
|
Rise at 4am
Peak at 8am |
|
When do cortisol levels reach their low during the day?
|
At midnight
|
|
What happens to normal people when you inject them with insulin?
|
They become hypoglycemic.
|
|
What is hypoglycemia?
|
Stress
|
|
What are the 3 responses to an insulin injection in a FASTED individual in the initial 30 min?
|
1. Blood glucose drops immediately
2. ACTH goes up starting at 30 min 3. Cortisol goes up then too |
|
What happens in fasted patients with hypopituitarism when you inject insulin?
|
1. Glucose drops
2. ACTH fails to go up 3. Cortisol fails to go up |
|
How would you test to see if that patient had primary adrenal insufficiency?
|
By giving CRH - if ACTH did go up, then that wouldn't be hypopituitarism, but adrenal insufficiency.
-Kill 2 birds w/ 1 stone |
|
What is the most common form of primary adrenal insufficiency?
|
Congenital Adrenal Hyperplasia
|
|
And why do we care about CAH?
|
Because it's the most common Congenital defect by far
|
|
How do you treat CAH?
|
With Dexamethasone
|
|
What is the primary cause of adverse symptoms in CAH?
|
-Loss of neg feedback
-Increased CRH/ACTH -Increased pregnenalone pumps into making androgens - virilism |
|
What do we call underproduction of cortisol? Overproduction?
|
Under: adrenal insufficiency
Over: Cushing's |
|
What is another name for primary adrenal insufficiency?
|
Addison's
|
|
What is 2ndary adrenal insufficiency?
|
When hypopituitarism causes atrophy, adrenal production of cortisol is then insufficient.
|
|
What is the cause of Cushing's?
|
A pituitary tumor that oversecretes ACTH
|
|
If there's overproduction of Cortisol in Cushing's, why doesn't it inhibit more ACTH output?
|
Because it's a tumor and refuses to be bossed around.
|
|
What is ACTH independent cushing's?
|
Overproduction of cortisol caused by an adrenal gland tumor.
|
|
What are ACTH levels in ACTH-independent cushing's?
|
Low
|
|
What is the cause of ACTH-dependent cushing's that is unrelated to the pituitary?
|
An ectopic ACTH-secreting tumor
|
|
How do you diagnose whether the tumor is pituitary or ectopic in ACTH-dependent cushing's?
|
By doing inferior petrosal sinus sampling to see if there is more ACTH in the pituitary than in the peripheral blood.
|
|
If there is an ACTH gradient, what does it tell you?
|
That the tumor is in the pituitary.
|
|
If there isn't a gradient what does that tell you?
|
The ACTH-secreting tumor is ectopic.
|
|
What are the 2 most common causes of Primary Adrenal Insufficiency?
|
80% Autoimmune
20% Tuberculosis |
|
And what do we call primary adrenal insufficiency?
|
Addison's
|
|
What causes 2ndary adrenal insufficiency?
|
Hypopituitarism which means there is no trophic stimulation of the adrenals so they shrink.
|
|
What is Congenital Adrenal Hyperplasia?
|
Primary adrenal insufficiency
|
|
What are the 4 MAJOR FEATURES in patients who present with primary adrenal insufficiency?
|
1. Weakness
2. Fatigue 3. Anorexia 4. Weight loss |
|
Why is it VERY important to treat these patients IMMEDIATELY?
|
Because it's fatal and soooo treatable and I don't want to be sued for malpractice.
|
|
Why do patients with primary adrenal insufficiency become darker?
|
Because the gene sequence for ACTH also includes MSH - when it's ramped up trying to get the adrenals to work, MSH increases.
|
|
What is Cosyntropin?
|
The ACTH type that is given to stimulate the adrenals and test for insufficiency.
|
|
When Adrenal Insufficiency is suspected, what should you do?
|
1. Test a basal plasma sample for ACTH and Cortisol levels
2. Give Cosyntropin 3. Measure cortisol at 30 min |
|
If cortisol levels are below normal after giving Cosyntropin, what does it mean?
|
The patient isn't responding to ACTH; adrenal insufficiency
|
|
How do you deterine if the adrenal insufficiency is primary or secondary?
|
Primary: ACTH will be high
Secondary: ACTH will be low |
|
What are the main symptoms of Cushing's?
|
-Moon face
-Fat pads -Red cheeks -Pendulous abdomen -Bruising -Thin skin / striae |
|
What are common side effects of Cushing's in women?
|
-Hirsutism
-Menstrual disorders |
|
What does Cushing's do to BP?
|
Hypertension - due to too much aldosterone
|
|
What are the 2 forms of ACTH-dependent Cushing's Syndrome?
|
-Cushing's disease (pituitary tumor)
-ectopic tumor |
|
What is the cause of ACTH-independent Cushing's syndrome?
|
An adrenal tumor
|
|
What do the vast majority of patients with ACTH dependent cushing's have?
|
A pituitary tumor
|
|
How do you determine if Cushing's is ACTH dependent or independent?
|
MEASURE ACTH!
|
|
If ACTH is high, how do you determine if it's a pituitary tumor or ectopic?
|
Inferior petrosal sinus sampling.
|