3.1.5. Autonomic Neurotransmitters Flashcards
In the parasympathetic nervous system, which neurotransmitter is released by the pre- and postganglionic fibers?
Acetylcholine (ACh)
In the sympathetic nervous system, which neurotransmitter is released by preganglionic fibers?
Acetylcholine (ACh)
In the sympathetic nervous system, which neurotransmitter is released by postganglionic fibers?
Norepinephrine (NE)
What is the parasympathetic response in the heart?
Decreased heart rate, decreased atrial and nodal automaticity, decreased conduction velocity, and little effect on the contractile force.
What is the parasympathetic response in blood vessels?
Dilation (drugs can act on M3 receptors, but there is no parasympathetic innervation).
What is the parasympathetic response in bronchioles?
Increased contraction
What is the parasympathetic response in the iris?
There is increased contraction in the sphincter muscle (miosis). Causes pupils to constrict.
What is the parasympathetic response in the GI tract?
Increase in motility and tone.
What is the parasympathetic response in sweat glands?
Slight increase in localized secretion.
What is the sympathetic response in the heart?
Increased heart rate, increased atrial and nodal automaticity, increased conduction velocity, and increased contractile force.
What is the sympathetic response in blood vessels?
Increased constriction and increased dilation (in select vascular beds like skeletal muscle and the liver).
What is the sympathetic response in bronchioles?
Increased relaxation.
What is the sympathetic response in the iris?
Increased contraction of the radial muscle (mydriasis). Causes the pupils to dilate.
What is the sympathetic response in the GI tract?
Decreased motility and tone.
What is the sympathetic response in sweat glands?
Decreased sweat secretion.