_____ is a neurotransmitter secreted by the parasympathetic postganglionic neurons.
Acetylcholine
Epinephrine
Norepinephrine
Dopamine - ✔✔ANSW✔✔..Acetylcholine
_____ is a neurotransmitter secreted by the sympathetic postganglionic neurons.
Acetylcholine
Epinephrine
Norepinephrine
Dopamine - ✔✔ANSW✔✔..Norepinephrine
A moderate increase in extracellular potassium will:
a. Increase heart rate due to a less negative EK
b. Decrease heart rate due to a less negative EK - ✔✔ANSW✔✔..Increase heart rate
due to a less negative EK
A patient suffering from congestive heart failure are was prescribed a drug called
digitalis, which indirectly acts to raise the intracellular concentration of Ca2+.
How would digitalis affect ventricular contraction?
Why does this help your patient? - ✔✔ANSW✔✔..-Increase the amount of calcium in
the sarcoplasm or in the T-tubules. -More calcium available for Troponin to use will
increase the force developed.
Absolute refractory effects - ✔✔ANSW✔✔..-*prevents occurrence of temporal
summation*
-b/c Na channel inactivation
Ach effects - ✔✔ANSW✔✔..-*dec HR*
-*dec contractile force*
-b/c activates muscarinic receptors
-cause Gi stimulation
-dec adenyl cyclase
, -dec cAMP
-dec HCN channel activity (HR)
-dec Ca channel = shorter plateau, less intracellular [Ca2+], less force
After your lab partner's spill, stress causes the medulla of your adrenal glands to
secrete epinephrine into your bloodstream, increasing your heart rate.
Why does Isuprel cause a similar effect? - ✔✔ANSW✔✔..Isuprel is a non-selective
*beta adrenoreceptor agonist*, an analog/*mimic of epinephrine*
Applying atropine will directly ______ ______ nerve activity ("tone") and ______ heart
rate
Atropine - ✔✔ANSW✔✔..-used as a cholinergic antagonist
-prevents activation of muscarinic ACh receptors (mAChR's)
-inc HR
Atropine has a(n) _____ effect on its target receptors, resulting in _______
parasympathetic activity.
Agonistic, increased
Antagonistic, increased
Agonistic; decreased
Antagonistic; decreased - ✔✔ANSW✔✔..Antagonistic; decreased
Atropine then ACh effects - ✔✔ANSW✔✔..-*normal HR*
-*normal force*
-atropine blocks mAChRs
-b/c plant alkaloid, block muscarinic receptors
Check all that apply.
Arteries have:
More elasticity than veins
Less elasticity than veins
Narrower lumen than veins
A thicker tunica media
A thicker tunica externa - ✔✔ANSW✔✔..-More elasticity than veins
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