ANS Julia deck Flashcards
How is the peripheral nervous system divided up?
Autonomic and somatic nervous systems
How is the autonomic nervous system divided up?
Sympathetic and parasympathetic nervous systems
What two neurotransmitters are associated only with the sympathetic nervous system?
Epinephrine and norepinephrine
What neurotransmitter is released by both parasympathetic and sympathetic neurons?
Acetylcholine
Where do parasympathetic preganglionic neurons synapse with postganglionic neurons?
At ganglia near target organ
What neurotransmitter do parasympathetic preganglionic neurons release? What kind of receptors are activated by this neurotransmitter at this location?
Acetylcholine; activates nicotinic receptors on postganglionic neurons
What neurotransmitter do parasympathetic postganglionic neurons release? What kind of receptors are activated by this neurotransmitter at this location?
Acetylcholine; activates muscarinic receptors on the target organ
Where do sympathetic preganglionic neurons synapse with postganglionic neurons?
In the paravertebral sympathetic ganglion, near the spinal cord.
What neurotransmitter do sympathetic preganglionic neurons release? What kind of receptors are activated by this neurotransmitter at this location?
Acetylcholine; activates nicotinic receptors on postganglionic neurons
What neurotransmitter do sympathetic postganglionic neurons release? What kind of receptors are activated by this neurotransmitter at this location?
Norepinephrine; activates adrenergic receptors on target organs
What autonomic nervous system controls sweat glands?
Sympathetic nervous system
The only postganglionic neurons in the sympathetic nervous system that release acetylcholine are in the…
sweat glands involved with thermoregulation.
What autonomic nervous system controls the smooth muscle of the renal vascular bed?
Sympathetic nervous system
What neurotransmitter do postganglionic sympathetic neurons release at the kidney vascular bed?
Dopamine – precursor to NE, causes vasodilation.
What is unique about sympathetic innervation of the adrenal glands?
The preganglionic neurons do not synapse in the paravertebral ganglion. Instead, preganglionic neurons synapse directly on the adrenal gland and release acetylcholine to nicotinic receptors. Adrenal glands act like the postganglionic neuron because the release epinephrine.
What are two other names for cholinergic drugs?
Muscarinic agonists and parasympathomimetics
What are two other names for muscarinic antagonists?
Anticholinergics and parasympatholytics
What are two other names for sympathomimetics?
Adrenergics or adrenergic agonists
What are two other names for antiadrenergics?
Adrenergic antagonist and sympatholytic
Name three parts of the body where you can find nicotinic receptors.
Ganglion, skeletal muscle, and neuronal CNS
How many subunits compose the nicotinic receptor?
Five
Where is the M3 muscarinic receptor found?
Smooth muscle in glands – causes contraction that releases gland contents
Where is the M2 muscarinic receptor found?
The heart – decreases heart rate.
What kind of receptor is a muscarinic receptor?
A 7 transmembrane domain GPCR or heterotrimeric G protein receptor
What kind of G alpha subunit do M1, M3, and M5 receptors release?
Gq subunits
What net effect does M1, M3, and M5 receptor activation cause?
Activation of protein kinase C (PKC) and increased levels of calcium
What effector does the Gq subunit act on once activated by M1, M3, or M5 receptors?
Phospholipase C (PLC) which splits PIP2 into DAG and IP3
What kind of G alpha subunit do M2 and M4 receptors release?
Gio subunits
What is the net effect of M2 and M4 receptor activation?
Decreased cAMP formation, which decreases PKA activity, and opening of potassium channels.
In what major organ are alpha-1 adrenergic receptors located and what is their effect?
In the smooth muscle around arteries – causes vasoconstriction which increases BP
In what major organ are alpha-2 adrenergic receptors located and what is their effect?
In the cardiovascular control center of the brainstem – they turn off the sympathetic nervous system (?)
In what major organ are beta-1 adrenergic receptors located?
The heart
In what major organ are beta-2 adrenergic receptors located?
Smooth muscle
Alpha 1 adrenergic receptors activate Gq, activating PLC and eventually leading to increased calcium in the cell and activated PKC. What other receptor(s) is alpha 1 similar to?
M1, M3, and M5 receptors
What G alpha subunit do alpha-2 adrenergic receptors activate?
Gi
What is the net effect of alpha-2 activation?
Decreased levels of cAMP, leading to less kinase activity
What G alpha subunit do beta adrenergic receptors activate?
Gs
What is the net effect of beta adrenergic activation?
Increased levels of cAMP, leading to increased kinase activity.
What receptors in the heart decrease rate and force of contraction?
M2 receptors – parasympathetic
What receptors in the heart increase rate and force of contraction?
B1 > B2
What receptors in most arteries and veins cause vasodilation?
Trick question – only the sympathetic system innervates arteries and veins, and sympathetic stimulation causes vasoconstriction. A decrease in sympathetic activation causes vasodilation.
What receptors in skeletal muscle arteries cause vasodilation?
B2 receptors – sympathetic
What receptor causes endothelium to release EDRF?
M3 receptors – parasympathetic
What receptor causes bronchodilation in the lungs?
B2 receptors – sympathetic
What receptor causes bronchoconstriction in the lungs?
M2 and M3 receptors – parasympathetic
What receptor causes relaxation of the bladder wall?
B2 receptors – sympathetic
What receptor causes contraction of the bladder wall?
M3 receptors – parasympathetic
What receptor causes contraction of the ureter and sphincter?
A1 receptors – sympathetic
What receptor causes relaxation of the ureter and sphincter?
M3 – parasympathetic
What parasympathetic receptor plays a role in a pregnant uterus?
M3 receptor
In the pregnant uterus, what sympathetic receptor causes relaxation? Contraction?
Relaxation – B2 (target if premature contractions) Contraction – A1
What receptor causes erection of the penis?
M3 – parasympathetic
What receptor causes penile ejaculation?
A1 – sympathetic (sperm flight)
In what gland do sympathetic and parasympathetic receptors have the same response?
Salivary gland
What two receptors causes increased salivary secretion?
A1 (sympathetic) and M3 (parasympathetic)
What receptor causes increased GI secretion?
M2 and M3 – parasympathetic
What receptor inhibits GI secretion?
A2 – sympathetic
What receptors cause both GI wall contraction and GI sphincter relaxation?
M2 and M3 – parasympathetic
What receptor causes contraction of GI sphincters?
A1 receptors – sympathetic
What receptor causes relaxation of GI walls?
A2 and B2 receptors – sympathetic
What receptor causes contraction of hair follicles and goosebumps?
A1 – sympathetic
True or false: All tissues are innervated by both the sympathetic and parasympathetic nervous system
False – one example is skin, which is innervated only by the sympathetic nervous system
What receptor is responsible for inducing sweating for thermal regulation?
M3 – SYMPATHETIC (only instance)
What receptor is responsible for inducing sweating in response to stress?
A1 receptor – sympathetic
What receptor is responsible for causing contraction of the radial muscle in the eye?
A1 receptor – sympathetic
Radial muscle contraction causes pupil…
dilation (mydriasis).
Circular muscle contraction causes pupil…
contraction (miosis).
What receptor is responsible for causing contraction of the circular muscle in the eye?
M3 receptor – parasympathetic
What receptor is responsible for causing ciliary muscle contraction?
M3 receptor – parasympathetic
Ciliary muscle contraction causes the lens to adjust to ___ vision.
near (short distance)
Ciliary muscle relaxation causes the lens to adjust to ____ vision.
far (long distance)
What receptor is responsible for stimulating the secretion of aqueous humor in the eye?
B2 – sympathetic.
If an eye doctor wanted to dilate your eye, what two types of agents could he administer?
M3 receptor antagonist (parasympatholytic) to stop contraction of the circular muscle (what they actually do) or A1 receptor agonist (sympathomimetic) to cause contraction of the radial muscle.
What receptor increases renin secretion in the kidney?
B1 – sympathetic
List locations and functions of A1 receptors.
Vasoconstriction in arteries and veins, contraction of the ureter and urinary sphincter, penile ejaculation, contraction of the uterus, increased salivary secretion, contraction of sphincters in GI tract, contraction of hair follicles and goosebumps in skin, stimulation of sweating due to stress, contraction of the radial muscle in the eye, metabolic changes in liver and fat
List locations and functions of A2 receptors.
Vasoconstriction in veins, relaxation of GI walls, inhibition of GI secretion, decrease in insulin release from the pancreas
List locations and functions of B1 receptors.
Increase in the rate and force of contraction in the heart. increase in renin secretion from the kidneys.
List locations and functions of B2 receptors.
Vasodilation in smooth muscle vasculature, bronchodilation in the lungs, bladder wall relaxation, uterus relaxation, GI wall relaxation, some minor relaxation of ciliary muscle and minor effects on heart.
List locations and functions of M2 receptors.
Decrease in heart rate and force of contraction, bronchoconstriction, increased GI secretion, GI wall contraction, and GI sphincter relaxation.
List locations and functions of M3 receptors.
Release of EDRF from endothelium, bronchoconstriction, all parasympathetic responses in GU and GI systems, contraction of the ciliary muscle and circular muscle, and sympathetic sweat secretion in response to heat.
What type of agent is atropine?
A long-acting tertiary amine antimuscarinic
What type of agent is anisotropine?
A quaternary amine antimuscarinic
What type of agent is scopolamine?
A long-acting tertiary amine antimuscarinic
Which has higher CNS penetration–atropine or scopolamine?
Scopolamine
What type of agent is homotropine?
A short-acting tertiary amine antimuscarinic
What type of agent is tropicamide?
A short-acting tertiary amine antimuscarinic