Endocrine Lecture 3: Adrenal Gland Flashcards
(40 cards)
Adrenal Anatomy:
The Cortex of the adrenal gland refers to the ____, the Medulla refers to the ____.
Outer “bark” = Cortex
inner region = Medulla
The Adrenal Medulla is directly connected to the _____ branch of the nervous system via nerves.
Sympathetic
The Adrenal Medulla releases ______, which are responsible for activation of our fight or flight responses.
Catecholamines
What cells in the adrenal medulla are responsible for creating catecholamines?
Chromaffin cells
Catecholamines are derived from what substance?
Tyrosine
What are the 4 catecholamines that are produced in the Adrenal Medulla?
DOPA [Aromatic L-amino acid decarboxylase (AADC or AAAD), also known as DOPA decarboxylase]
Dopamine
Epinephrine
Norepinephrine
_____ is the principal product of the Adrenal Medulla and is ONLY made in the Adrenal Medulla.
Epinephrine
Of the catecholamines made in the Arenal Medulla, 80% is ______ and 20% is ______ . Only a scant amount of ____ is made in the Adrenal Medulla as well.
80%= Epinephrine
20%= Norepinephrine
scant amount = Dopamine
Norepinephrine and Dopamine are primarily made elsewhere in the body.
Epinephrine and Norepinephrine have strong alpha-1 effects which results in ______?
Arterial vasoconstriction most importantly
- Bronchoconstriction
- Inhibits insulin secretion
- Stimulates glycogenolysis (↑blood sugar) and gluconeogenesis
- Mydriasis-eyes open wide
- GI relaxation
- Activation increases intracellular Ca (neurotransmitter release)
- Smooth muscle contraction
Epinephrine has stronger beta-1 effects which results in ____ and _____.
Increased HR
and
Contractility
Beta-1 (Target for Beta blockers)
-↑HR, ↑Conduction velocity, ↑myocardial contractility (inotropy)
Norepinephrine is converted to Epinephrine by what enzyme?
Phenylethanolamine N-Methyltransferase (PNMT)
PNMT expression is regulated by ________, which accounts for ______’s role in affecting BP.
Glucocorticoids (cortisone)
_________ is a tumor either caused by adrenal medullary hyperplasia or extra-adrenal chromatin tissue
Pheochromocytoma
Pheochromocytoma tumors make and release _______ in an unregulated fashion.
Catecholamines
Symptoms of pheochromocytoma include:
paroxysmal HTN tachycardia HA sweating anxiety tremor glucose intolerance
T/F: Most pheochromocytoma (85-90%) are solitary tumors localized to a single adrenal gland (usually the R side)
True
10-15% of Pheochromocytomas are extra-medullary, of these most are found in the _______.
Abdomen
Diagnosis of Pheochromocytoma is made by testing _____ for the presence of _______.
Urinary Vanillymandelic acid (VMA) through a 24 hour urine collection.
Both Epi and Norepi are degraded into VMA
The introduction of alpha adrenergic antagonist preoperatively reduces the incidence of _______
preoperative blood pressure fluctuations MI CHF Dysrhythmias CVA
Alpha blockers phenoxybenzamine or parson should be started _____ days prior to surgery to normalize BP.
10-14 days before surgery
Once alpha blockage is established, beta blockage can begin. Why is this?
Beta blockage is delayed B/C of the risk of unopposed alpha mediated vasoconstriction.
When arteries do relax, volume expansion is necessary.
What medications should be avoided intraoperatively to prevent provocation of pheochromocytomas?
Histamine releasing agents
metoclopramide
glucagon
When a Pheochromocytoma tumor is removed, ______ can happen.
abrupt hypotension
(as catecholamine levels drop and alpha and beta blockade are unopposed), blood resuscitation may be required sometimes pressers are needed.
Following removal of pheochromocytoma tumor removal, catecholamine levels return to normal after a few days and about ____% of patients become normotensive within _____ days.
75%
10 days
