Adrenal Medullary Hormones Flashcards
What type of molecule is adrenaline?
Catecholamine
Which tissues produce catecholamines?
Brain
Nervous Tissue
Adrenal Gland
What are the functions of catecholamines?
Act as neurotransmitters when released by brain and nervous system
Act as hormones when released into blood by adrenal gland
All catecholamines are …
… monoamine molecules
What is adrenaline derived from?
Phenylalanine
Dopamine is a ____ to adrenaline
____ precursor ____
Where is dopamine produced?
Adrenal Medulla
Is dopamine released by the adrenal gland?
No it acts as a neurotransmitter in the CNS
How does dopamine effect the blood vessels?
Vasoconstriction
Can be used in patients with septicemia
Which receptors does adrenaline bind to?
α2
β1
β2
Adrenaline does not bind strongly to α1 receptors which prevents it from exerting α1-adrenergic action which causes constiction of blood vessels
What type of receptors are adrenergic receptors?
G-protein coupled receptors
What are the effects of adrenaline?
Increases heart rate
Increases force of contraction
Causes vasodilation
Relaxes bronchi
Promotes conversion of glycogen to glucose
Inhibits insulin release
In what clinical cases can adrenaline be used?
Anaphylactic reaction
Binding of adrenaline to α2 receptors causes …
inhibition of lipolysis and of insulin release
Binding of adrenaline to β1 receptors causes …
Increase heart rate
Increasing ventricular contractility
Increase renin secretion
When is adrenaline released?
Under stressful situations:
Fear
Pain
Anxiety
Surgery
High and low temp.
Signals to increase adrenal synthesis come from …
… neural and hormonal inputs
Describe the pathway of neural action of adrenaline
Describe the hormonal pathway of catecholamine synthesis
ACTH binds to adrenal medulla receptors
Stimulate catecholamine synthesis by inducing key enzymes
What effect does serum adrenaline concentration affect adrenaline secretion?
Adrenaline secretion does not downregulate its own secretion
In the condition ____, a person’s adrenaline levels can get very high
pheochromocytoma
What are the potential outcomes of adrenaline?
Taken up into the nerve terminals
Diluted in bloodstream
Metabolized by enzymes monoamine oxidaseandcatechol-O-methyl transferase
