Autonomic Nervous System Flashcards
What does the PNS system break down to?
SNS + ANS
What does the SNS system break down to?
It doesn’t
What does the ANS system break down to?
Sympathetic + Parasympathetic + ENS
What does the ANS innervate and regulate?
Smooth muscles, cardiac muscles, and glands
The somatic NS has #__ neuron(s)
1
The autonomic NS has #__ neuron(s)
2
Somatic vs Autonomic
Which projects directly to effector organ?
Somatic
Somatic vs Autonomic
Which links CNS to skeletal muscles?
Somatic
Somatic vs Autonomic
Which has a large diameter and conducts rapidly?
Somatic
Somatic vs Autonomic
Which has motor neurons?
Autonomic
Somatic vs Autonomic
Which has alpha motor neurons?
Somatic
Somatic vs Autonomic
Which projects from CNS to visceral organs?
Autonomic
Somatic vs Autonomic
Which contains preganglionic and postganglionic fibers?
Autonomic
Sympathetic and parasympathetic systems usually have _____ effects on visceral targets
opposite
Sympathetic and parasympathetic systems usually have opposite effects on ______ targets
visceral
Sympathetic preganglionic neurons originate in the _________________
lateral horn of the spinal cord
Sympathetic preganglionic neurons originate from segments ____ - ____
T1 + L3
Sympathetic preganglionic neurons exit the spinal cord via the ____ ___
ventral root
Sympathetic preganglionic neurons synapse between neurons made in the autonomic ganglia located where?
Paravertebral chain
Sympathetic preganglionic neurons located in the paravertebral chain are made where?
autonomic ganglia
Where do parasympathetic preganglionic neurons originate from?
Nuclei of cranial nerves III, VII, IX, and X + spinal cord segments S2-S4
Where do parasympathetic preganglionic neurons synapse?
Between neurons that are made in autonomic ganglia
Where is the parasympathetic ganglia located?
In or near effector organ
Where do both sympathetic and parasympathetic ganglia synapse?
Autonomic ganglia
Where do parasympathetic preganglionic neurons synapse?
Autonomic ganglia
Where do both sympathetic/parasympathetic postganglionic neurons have their cell bodies?
Autonomic ganglia
The adrenal medulla is regarded as a modified ______ _____ neurons
postganglionic sympathetic
Preganglionic fibers synapse directly on _____ cells in the adrenal medulla
chromaffin
_____ is/are the receptor(s) in the ganglia at eh parasympathetic postganglionic neuron, sympathetic postganglionic neuron, at the adrenal medulla, and at eh neuromuscular junction
Nicotinic receptor, Nm, and Nn
Preganglionic fibers synapse directly on chromaffin cells in the adrenal medulla and secrete _____
ACh
The chromaffin cells secrete _____ and _____
Epinephrine and norepinephrine (4:1)
Norepinephrine and epinephrine is released by adrenergic neurons that are _____ ______ neurons
sympathetic postganglionic
Acetylcholine is released by cholinergic neurons that are:
A. Sympathetic preganglionic
B. Parasympathetic postganglionic
C. Sympathetic postganglionic
D. Parasympathetic preganglionic
A, B, + D
What are the main neurotransmitters of the ANS?
- Substance p
- Vasoactive intestinal peptide (VIP)
- Nitric Oxidie (NO)
What are the subtypes of adrenergic receptors?
A1 + A2 + B1 + B2
Epinephrine is more likely to bind to ___ receptors
beta
Norepinephrine is more likely to bind to _____ receptors
alpha + beta
What do sympathetic postganglionic neurons release?
Norepinephrine
What do parasympathetic postganglionic neurons release?
Acetylcholine
What do sympathetic preganglionic neurons release?
Acetylcholine
What do parasympathetic preganglionic neurons release?
Acetylcholine
Cholinergic receptors are nicotinic receptors that are located where?
Sympathetic + parasympathetic postganglionic neurons
Which receptors constrict blood vessels in the skin?
A1
Maintains body heat by constricting blood vesels
A1
A2
B1
B2
A1
Constricts bladder + GI sphincters
A1
A2
B1
B2
A1
Contracts radial muscles of iris, which dilates pupils
A1
A2
B1
B2
A1
Found in the wall of the GI tract
A1
A2
B1
B2
A2
Inhibits GI secretion + reduced GI motility
A1
A2
B1
B2
A2
Mechanism involves Gi activation
A1
A2
B1
B2
A2
Mechanism involves Gq activation
A1
Found in the SA + AV nodes ventricular muscles of the heart
A1
A2
B1
B2
B1
Increases HR, AV conduction velocity and increase contraction
A1
A2
B1
B2
B1
Mechanism involves Gs activation
A1
A2
B1
B2
B1
Found in the vascular smooth muscle of skeletal muscle
A1
A2
B1
B2
B2
Found in the vascular smooth muscles of the skin
A1
A2
B1
B2
A1
Found in the GI tract, bladder and spincters
A1
A2
B1
B2
A1
Found in the bronchial smooth muscles
A1
A2
B1
B2
B2
Found in the wall of the GI tract and bladder
A1
A2
B1
B2
B2
Which dilates vascular smooth muscle?
A1
A2
B1
B2
B2
Which dilates bronchioles?
A1
A2
B1
B2
B2
Which decreases GI secretion?
A1
A2
B1
B2
B2
Which relaxes bladder wall?
B2
Mechanism involves activation of Gs
A1
A2
B1
B2
B2
Activating Gq does what?
Stimulates PLC, increases IP3 and intracellular calcium
Activating Gi does what?
Inhibits adenylate cyclase + decreases cAMP
Activating Gs does what?
Stimulates adenylate cyclase + increases cAMP
A1 receptors involve what G protein?
Gq
A2 receptors involve what G protein?
Gi
B1 receptors involve what G protein?
Gs
B2 receptors involve what G protein?
Gs
Nicotinic receptors are found where?
Autonomic ganglia (Nn) of parasympathetic + sympathetic NS, neuromuscular junction (Nm) and the adrenal medulla
What is the antagonist to nicotinic receptors?
Hexamethonium (at autonomic ganglia)
How does hexamethonium work?
Binds to alpha subunit of nicotinic ACh receptors
What are the agonist to nicotinic receptors?
Nicotine or ACh
What are the agonist to muscarinic receptors?
Muscarine or ACh
What is an antagonist to muscarinic receptors?
Atropine
Where are muscarinic receptors found?
Heart (M2), Smooth muscles (M3), and glands (M3)
What happens if ACh is bound to a muscarinic receptor?
Agonist; inhibitory in the heart + excitatory in smooth muscles/glands
What is the mechanism behind muscarinic receptors?
In the SA node, agonists bind and activate Gi, which opens K+ channels, slows rate of depolarization and decreased HR
In smooth muscles/glands, activates Gq
A1 _____ blood vessels
constricts
A1 ______ bladder
constricts
A1 ______ radial muscles
contracts
A1 _______ pupils
dilates
A2 _____ GI secretion + motility
inhibits/reduces
B1 _____ heart rate
increases
B1 is found on the (atrial/ventricular) muscles of heart
ventricular
B2 _____ vascular smooth muscles
dilate
