ANS I Flashcards
What is an agonist? what is an antagonist?
- agonist = activator
2. antagonist = inactivator
What do the following terms mean:
- ionotropic
- chronotropic
- dromotropic
- ligand gated
- affecting heart rate
- affects AV node- conduction of speed
What are the sympathetic effects on the heart?
- stimulation of heart rate at SA node
- stimulation of AV nodal conduction
- stimulation of myocardial contractility
What are the PNS effects on the heart?
- Inhibition of HR at SA node
- inhibition of AV nodal conduction
- inhibition of atrial contractility
Which neurons are myelinated, preganglionic or postganglionic ?
preganglionic
What transmitter do somatic neurons release? and what receptor does it bind to?
- ACh
- binds to N1 nicotinic cholinergic receptors
What transmitter do preganglionic ANS neurons release and what receptors does it bind to?
- ACh
- binds to N2 nicotinic cholinergic receptors
What transmitter does a postganglionic parasympathetic neuron release and what receptor does it bind to?
- ACh
- muscarinic cholinergic
What transmitter do postganglionic sympathetic neurons release and what receptors does it bind to?
- Norepinephrine
- alpha or beta adrenergic
What neuron activates the adrenal medulla, and how is this accomplished?
- Sympathetic preganglionic neurons release Ach to chromaffin cells
- these cells release epinephrine (80%)
Why is sympathetic stimulation of the adrenal medulla long lasting?
The hormones released are inactivated slower
When is there an exception to the receptors the sympathetic neurons usually stimulate?
Eccrine glands - muscarinic cholinergic receptors
Which type of receptors are ionotropic?
Nicotinic cholinergic - N1, N2
Na+/K+ ligand gated channel
What is the antagonist of N1 receptors?
D-tubocurarine
What is the antagonist of N2 receptors ?
Hexamethonium
What is the antagonist of the M1,M3, M5 muscarinic receptors?
atropine
Name the following for M1, 3 ,5 receptors:
- G protein
- Linked Enzyme
- Secondary messengers
- G alpha q
- PLC
- IP3 and DAG
Name the following for M2,4 receptors:
- G protein
- Linked Enzyme
- Secondary messengers
- G alpha 1 and G alpha 0
- adenylyl cyclase
- Decreased cAMP
Name the following for alpha1 adrenergic receptors:
- G protein
- Linked Enzyme
- Secondary messengers
- G alpha q
- PLC
- IP3 and DAG
Name the following for beta adrenergic receptors:
- G protein
- Linked Enzyme
- Secondary messengers
- G alpha S
- adenylyl cylcase
- increased cAMP
What is the antagonist of M2 , 4 receptors?
Atropine
What is the antagonist of B1 adrenergic receptors?
Propanolol
What are some of the effects of the sympathetic nervous system? (8)
- Inc mydriasis and eyelid retraction
- Inc HR and force of contraction
- Inc bronchial dilation
- Inc vasoconstriction (vasodilation to active muscles)
- Inc sweating
- Inc cell. Metabolism
- Dec GI motility – smooth muscle walls
- Inc contraction of sphincters
Which sympathetic effects result from stimulation of alpha 1 receptors? (3)
- Mydriasis and eyelid retraction
- vasoconstriction
- contraction of sphincters
ex. receptor in the internal sphincter found in the bladder
Which sympathetic effects result from stimulation of beta 1 receptors? (1)
- Increased heart rate and force of contraction
Which sympathetic effects result from stimulation of beta 2 receptors? (2)
- bronchial dilation
- also on the detrusor muscle in the bladder for relaxation
Which sympathetic effects result from stimulation of both alpha and beta receptors? (2)
- decreased GI motility - smooth muscle walls
2. increased cellular metabolism - epi from medulla
What receptors does epinephrine have a greater affinity for? Where do these primarily exist?
Beta adrenergic – heart, liver, lungs
What does norepinephrine have a greater affinity for? Where are these primarily expressed?
Alpha adrenergic receptors - vasculature
What hormone does the adrenal medulla secrete more of?
80 % epinephrine
20% norepinephrine
What stimulates the conversion from norepinephrine to epinephrine?
Cortisol
