Where are the ganglia of the Parasympathetic Nervous System located?
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They are located close to or on the target organ.
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Where are the ganglia of the Parasympathetic Nervous System located?
They are located close to or on the target organ.
What is the length of post-ganglionic motor neurons in the Sympathetic Nervous System (SNS)?
Long.
Where are autonomic integrating areas located in the brain?
In the brainstem and hypothalamus.
What type of receptors does acetylcholine bind to on the postganglionic neuron in the SNS?
Nicotinic cholinergic receptors (Nn)
What are the exceptions to the typical neurotransmitter and receptor pairing in the SNS?
Acetylcholine binds to muscarinic receptors on sweat glands and dopamine on renal vascular smooth muscle.
Where are epinephrine and norepinephrine released into and what do they bind to?
They are released into the blood and bind to adrenergic receptors.
What nature are the effects of the sympathetic nervous system?
Primarily catabolic.
What is the effect of adding epinephrine to lidocaine in local anesthesia?
It usually extends the duration of anesthesia by at least 50%.
What do afferent (sensory) fibers do in the autonomic reflex arc?
They carry the stimulus information to the CNS.
What is the difference between a short reflex and a long reflex in the autonomic nervous system?
A short reflex bypasses the CNS, while a long reflex involves the CNS.
What is the appropriate reflex response of the parasympathetic division of the autonomic nervous system to raise blood pressure?
The parasympathetic division generally does not act to raise blood pressure; it primarily functions to lower heart rate and promote relaxation.
What neurotransmitter is released by the postganglionic neuron in the PNS?
Acetylcholine
What is the function/use of an EPI Pen?
It utilizes epinephrine, which has a higher affinity for β2 receptors.
Are the effects of the parasympathetic nervous system primarily anabolic or catabolic?
Primarily anabolic in nature.
What types of tissues does the somatic nervous system innervate?
The somatic nervous system innervates skeletal muscle.
What does the adrenal medulla release when activated in the SNS?
Epinephrine (80%) and norepinephrine (20%) as neurohormones.
What are some major effects produced by postganglionic fibers entering the thoracic cavity in sympathetic nerves?
Acceleration of heart rate and increasing the strength of cardiac contractions; dilation of respiratory passageways.
Why is an EpiPen used for allergic reactions?
Because epinephrine (EPI) has a greater affinity for β2 receptors than norepinephrine (NE).
What is the role of the pre-ganglionic neuron in the autonomic reflex arc?
It transmits signals from the CNS to the autonomic ganglion.
What neurotransmitter is released by the preganglionic neuron in the PNS?
Acetylcholine
What is the function of the nicotinic receptor in the PNS?
It is a non-specific cation channel that allows Na+ influx and K+ efflux, causing depolarization.
What causes muscle relaxation in relation to acetylcholine release?
Relaxation occurs when the nerve stops releasing acetylcholine.
Which adrenergic receptor does norepinephrine (NE) activate more than β2?
β1
What is the main difference in the effects of the PNS compared to the SNS?
The PNS tends to have more localized effects in the body, such as urination, versus the mass activation of many tissues at once that occurs in the SNS.
What are some gastrointestinal side effects of anticholinergic drugs?
Xerostomia (dry mouth), constipation, ileus, and nausea and vomiting.
What are some actions of the parasympathetic nervous system (PNS)?
Digestion, urination, miosis, bronchoconstriction, bradycardia, lacrimation, and salivation.
What are the effector organs in the Sympathetic Nervous System (SNS)?
Heart, stomach, etc.
What types of tissues does the autonomic nervous system innervate?
The autonomic nervous system innervates smooth muscle, cardiac muscle, glands, and adipose tissue.
What is the term for the phenomenon where both divisions of the autonomic nervous system innervate most effector organs?
Dual innervation.
What type of response can the autonomic nervous system cause at the target organ synapse?
The autonomic nervous system can be either excitatory or inhibitory at the target organ synapse, depending on the specific receptor on the target cell.
What is albuterol, and what is it used for?
Albuterol is a Beta 2 selective agonist used for the treatment of asthma as it causes bronchodilation by relaxing smooth muscle.
What happens to blood pressure during a hemorrhage?
Blood pressure initially decreases.
What type of receptors are all muscarinic receptors?
GPCRs (G protein-coupled receptors)
Where are M4 muscarinic receptors primarily located?
CNS and Vagus nerve
Which adrenergic receptor does epinephrine (EPI) have a higher affinity for compared to norepinephrine (NE)?
β2
What is the length of pre-ganglionic motor neurons in the Sympathetic Nervous System (SNS)?
Short.
From which regions of the spinal cord do the pre-ganglionic neurons of the SNS exit?
Thoracic and lumbar regions.
What neurotransmitter is released by the postganglionic neuron in the SNS?
Norepinephrine
How many neurons are involved in the autonomic nervous system pathway between the CNS and target organs?
The autonomic nervous system consists of two neurons (pre-ganglionic and post-ganglionic) that synapse in ganglia. The post-ganglionic neuron synapses with the target organ.
What describes the Sympathetic Nervous System (SNS) activity?
Fight-or-flight.
When does the sympathetic nervous system dominate?
When the body is stressed—physically or emotionally.
What are the names of the two neurons that run from the CNS to effector organs in the Autonomic Nervous System?
Preganglionic neuron and postganglionic neuron.
What is the term for gray matter in the peripheral nervous system where synaptic communication occurs?
Ganglia.
What is the function of the integrating center in the spinal cord or brain in autonomic reflexes?
It processes the sensory information and generates a response.
How does the body detect a decrease in blood pressure during a hemorrhage?
Receptors called baroreceptors detect the decrease and activate afferent nerve fibers that send a message to the CNS.
Which muscarinic receptors activate Gq-PLC receptors and increase intracellular Ca2+?
M1, M3, and M5
What are the primary locations of M5 muscarinic receptors?
CNS
Where does the pre-ganglionic neuron of the Parasympathetic Nervous System exit?
It exits the brain and sacral region of the spinal cord.
Why are the ganglia of the SNS located close to the CNS?
Because the pre-ganglionic neurons are short.
What does the autonomic nervous system control?
The autonomic nervous system controls the visceral functions of the body by monitoring (sensory) and adjusting (motor) the activity of cardiac muscle, smooth muscle, glands, and adipose tissue.
How many neurons are involved in the somatic nervous system pathway between the CNS and skeletal muscle?
The somatic nervous system consists of a single neuron between the CNS and skeletal muscle.
What describes the Parasympathetic Nervous System (PNS) activity?
Rest and digest.
What happens to SNS activity when PNS activity increases?
SNS activity decreases.
What are varicosities used for in the Autonomic Nervous System?
They are used at the synapse between the postganglionic neuron and the effector cell.
What is the baroreceptor reflex?
An autonomic reflex that regulates blood pressure.
Which receptor does acetylcholine bind to on the target organ in the PNS?
Muscarinic cholinergic receptors
What are the primary locations of M3 muscarinic receptors?
Exocrine glands, smooth muscle (bladder, airways), endothelium, and sweat glands (sympathetic function)
What are the characteristics of pre-ganglionic and post-ganglionic motor neurons in the Parasympathetic Nervous System (PNS)?
The PNS has long pre-ganglionic motor neurons and short post-ganglionic motor neurons.
What condition can cause sialorrhea (drooling) in patients taking certain medications?
Taking anti-cholinesterases, such as those used in the treatment for Alzheimer’s Disease.
Which part of the nervous system dominates at rest?
The parasympathetic nervous system.
What neurotransmitter is released by the preganglionic neuron in the sympathetic nervous system (SNS)?
Acetylcholine
What are the two divisions of the Autonomic Nervous System?
Sympathetic and Parasympathetic.
What type of response can the somatic nervous system cause at the neuromuscular junction?
The somatic nervous system can only cause excitation at the neuromuscular junction because ACh binds to nicotinic ACh receptors on skeletal muscle cells.
Where do the two neurons of the Autonomic Nervous System synapse?
In structures called ganglia.
What is the role of receptors in peripheral tissue in the autonomic reflex arc?
They detect stimuli and activate afferent (sensory) fibers.
What is the role of the post-ganglionic neuron in the autonomic reflex arc?
It transmits signals from the autonomic ganglion to the peripheral effector.
Which receptor does acetylcholine bind to on the postganglionic neuron in the PNS?
Nicotinic cholinergic receptors (Nn)
What are the primary locations of M1 muscarinic receptors?
Stomach (secretions) and salivary glands
What is the mechanism of action of anticholinergic drugs like amitriptyline (Elavil)?
They inhibit the effects of acetylcholine (ACH) systemically via muscarinic receptors.
Where are the ganglia of the Sympathetic Nervous System (SNS) located?
Close to the CNS.
What can the Sympathetic Nervous System (SNS) do during a stress response?
Selectively activate effectors or elicit a mass discharge.
What type of receptors does norepinephrine bind to on most target organs in the SNS?
Adrenergic receptors (α/β)
What are some major effects produced by sympathetic postganglionic fibers in spinal nerves?
Constriction of cutaneous blood vessels, reduction in circulation to the skin and most other organs in the body wall; acceleration of blood flow to skeletal muscles and brain; stimulation of energy production and use by skeletal muscle tissue; release of stored lipids from subcutaneous adipose tissue; stimulation of secretion by sweat glands; stimulation of arrector pili; dilation of the pupils and focusing for distant objects.
What cells in the adrenal medulla contain the enzyme phenylethanolamine-N-methyltransferase (PNMT), and what does this enzyme do?
Chromaffin cells contain PNMT, which catalyzes the conversion of norepinephrine to epinephrine.
Which system is usually predominant at rest?
Parasympathetic Nervous System (PNS).
How does the addition of epinephrine affect the systemic absorption of injected local anesthetics?
Epinephrine causes vasoconstriction (via alpha 1 receptors) at the site of administration, decreasing blood absorption, facilitating neuronal uptake, enhancing quality of analgesia, prolonging duration of action, and limiting toxic side effects.
To which receptors do epinephrine (EPI) and norepinephrine (NE) bind?
They bind to α1, α2, β1, β2, and β3 receptors.
What is the function of the autonomic ganglion in the autonomic reflex arc?
It serves as a relay station where the pre-ganglionic neuron synapses with the post-ganglionic neuron.
What is the appropriate reflex response of the sympathetic division of the autonomic nervous system to raise blood pressure?
The sympathetic division will increase heart rate and cause vasoconstriction to raise blood pressure.
Which muscarinic receptors inhibit adenylyl cyclase and regulate specific ion channels via Gi coupling?
M2 and M4
What happens when acetylcholine binds to the NM receptor?
It elicits muscle contraction.
Where are M2 muscarinic receptors primarily found?
Myocardium, cardiac autorhythmic cells, and smooth muscle (GI sphincters)
