Autonomic Nervous System Flashcards
What are the components of the CNS? The PNS? What are the different types of nerves that are part of the PNS?
What do somatic efferent nerves do? What about visceral efferent nerves?
What do somatic afferent nerves do? What about visceral afferent nerves?
Which of the afferent/ efferent nerves are part of the somatic nervous system?
Which of the afferent/ efferent nerves are part of the autonomic nervous system?
What are visceral efferent and afferent nerves responsible for?
Visceral efferent and afferent axons are part of the autonomic nervous system responsible for involuntary control of smooth muscle, cardiac muscle, some glands and physiological life support functions (e.g., heart rate, blood pressure, digestion)
What does the somatic nervous system innervate? How many neurons does it have/ how is it structured?
What does the autonomic nervous system innervate? How many neurons does it have/ how is it structured?
True or False: Somatic nervous system has non myelinated axons.
FALSE
Does the autonomic nervous system have myelinated axons?
What systems does the autonomic nervous system regulate?
True or False:Changes in the level of afferent and efferent activity in sympathetic and parasympathetic nerves occur primarily independent of conscious or voluntary control.
TRUE
What are the components of the general visceral efferent (GVE)
- PNS, SNS, enteric nervous system
How many subdivisions are there for the Peripheral ANS? What are they based on?
The peripheral ANS is divided into two major subdivision (SNS)
based on the origin of their preganglionic neurons and on their synaptic transmitters at the target organ
True or False: All of the parts of the PANS originate in the CNS.
FALSE: The peripheral ANS has two subdivisions that originate in the CNS and one that does not
Sympathetic nerves have ____ preganglionic neurons and ____ postganglionic axons.
Short preganglionic and long postganglionic axons
How do preganglionic axons of the SNS leave the spine? Where do they enter?
- Preganglionic axons leave the spinal cord by way of the first thoracic through the third or fourth
lumbar spinal nerves. - The preganglionic axons pass through the ventral root and then to enter the paravertebral
sympathetic ganglion chain, the sympathetic trunk
Paraympathetic nerves have ____ preganglionic neurons and ____ postganglionic axons.
Long preganglionic and short postganglionic axons
Where do parasympathetic nerves originate from? How do preganglionic axons leave the CNS. Where do the preganglionic axons synapse?
- Parasympathetic nerves originate from cell bodies in the brainstem and sacral sections of the
spinal cord - Long preganglionic and short postganglionic axons
- The preganglionic axons leave the CNS by way of cranial nerves III (oculomotor), VII (facial),
IX (glossopharyngeal) and X (vagus) and several sacral spinal nerves - Preganglionic axons synapse in diffuse parasympathetic ganglia residing close to or within
(intramural ganglia), pelvic viscera
The enteric nervous system is….
Does it function independently or dependently on the CNS?
The enteric nervous system is an extensive network of interconnected sensory and motor interneurons
within the gastrointestinal wall that can control gut function independently of the CNS. However, its sensory and motor interneurons can also be influenced by the CNS through input from sympathetic
and parasympathetic subdivisions
What are the components of the enteric nervous system? What is it innervated by?
its characterized by the presence of a complex intrinsic neural network that includes the myenteric
plexus and the submucosal plexus
* Is extensively innervated by nonadrenergic-noncholinergic (NANC) nerve fibers
What has Dual ANS innervation? What is that?
Many organs and tissues are innervated by both sympathetic and parasympathetic arms of the ANS, dual ANS innervation (e.g., heart and urinary bladder)
SNS and PNS
True or false: In many instances physiologic responses produced by parasympathetic or sympathetic nerves to target tissue/ organ with dual innervation is usually functionally synergistic.
FALSE: In many instances physiological responses produced by activation of parasympathetic or sympathetic nerves to the target tissue or organ that receives dual ANS innervation are functionally antagonistic
If there is dual ANS innervation witll there be equal function/ balance function?
The presence of a dual ASN innervation does not indicate that the physiological function of that target is balanced to the same degree for each arm of the ANS. The basal physiological function of many organs is weighted towards either PSNS or SNS regulation
What organs only have sympathetic innervation?
Organs with only sympathetic innervation
* Adrenal medulla
* Peripheral blood vessels
* Pilomotor muscles
* Sweat glands
What is the adrenal medulla? What are chromaffin cells? What are they innervated by? What receptors are found here? What is synthesized/ released by chromaffin cells?
What is the primary neurtransmitter released from preganglionic neurons at sympathetic ganglionic sites? What receptor does it primarily bind to? What are the nerve fibers called that synthesize/ release ach? What are postganglionic cholinergic fibers? What receptors do they bind to?
What is the predominant neurotransmitter released from postganglionic SNS Neurons? What receptors does it bind? What are the nerve fibers called that synthesize/ release this neurotransmitter? What is another neurotransmitter that is released by soe postganglionic SNS neurons? What is it related to? What is it important for/ What does it bind to?
What is the predominant neurotransmitter released from preganglionic PNS Neurons? What receptors does it bind? What do the postganglionic PSNS neurons arise from? What is the primary neurotransmitter released from PSNS postganglionic neurons?
What does it bind to/ activate?
What are the Non-adrenergic and Non-cholinergic Neurotransmitters (NANC)?
- Adenosine triphosphate (ATP)
- Vasoactive Intestinal polypeptide (VIP)
- Neuropeptide Y (NPY)
- Serotonin (5-HT)
- Substance P
- Calcitonin gene-related peptide (CGRP)
- Nitric Oxide (NO)
Many of the same molecules/substances identified as _________ in ANS nerves also play a role as ________ released from NANC nerve endings
Many of the same molecules/substances identified as cotransmitters in ANS nerves also play a role as neurotransmitter released from NANC nerve endings
Where are cotransmitter molecules released from? What may be stored with ATP in the same vesicle and released together?
Cotransmitter molecules are released from many posganglionic fibers at target tissues
NE
What activates purinergic receptors? What are they identified as?
ATP mediates responses via activation of purinergic receptors that are identified as adenosine
P1 receptors and P2X and P2Y receptors
What is another NANC that is released with NE from sympathetic nerves? What is its function at neurokinin receptors Y1 and Y2? What is its role in sympathtic pre and postsynaptic sites?
Neuropeptide Y (NPY) can also be released with NE from sympathetic nerves. It is an agonist at
neurokinin receptors, Y 1 and Y2 .
NPY has the physiological role to modulate sympathetic
neurotransmission at both pre and postsynaptic sites.
What is released along with Ach from many postganglionic PSNS fibers at target tissues/ organs?
Cotransmitters are released along with Ach from many postganglionic PSNS fibers at target tissues
and organs
Parasympathetic nerves innervating the urinary bladder release ________ as a cotransmitter
ATP
Parasympathetic nerves innervating the salivary glands utilize _____________
as a cotransmitter
vasoactive intestinal polypeptide (VIP)
True or False: Cotransmitters have an important signaling role in the cardiovascular, urogenital, and respiratoy systems increasing pharmacological and physiological finesse in the regulation of tissue responses
True
What are the vesicle types that can be found at cholinergic nerve terminals?
Cholinergic nerve terminal contain several types of vesicles:
* Small membrane bound vesicles where ACh can be stored
* Large vesicles that contain biological substances
What protiens are utilized within vesicles for transport and trafficking? What are their purposes.
- Vesicles associated membrane proteins VAMPs play a role in aligning ACh-containing vesicles
- synaptosomal nerve-associated proteins SNAPs. SNAPs interact with vesicle-associated
membrane proteins to facilitate the fusion with the plasma membrane
What are neurons in the PSNS characterized by? What enzyme synthesizes Ach ? What is it synthesized from and where? What is it transported across the neuronal membrane by?
Neurons in the PSNS are characterized by high rates of ACh release
***** The enzyme choline acetyltransferase (ChAT) synthesizes ACh from acetyl-CoA and choline in the cytoplasm of cholinergic nerves
* Choline is transported across the neuronal membrane from the extracellular space via a **sodium-
dependent membrane choline transporter (CHT) **
What is a quanta?
Ach storage in vesicles characterized by packaging “quanta” of Ach molecules ( 1,000- 50,000 each vesicle.)
What is enzyme inactivates Ach in the synaptic space? How does it do that? What are its metabolites? Where is it located?
ACh located in the synaptic space is inactivated by acetylcholinesterase (AChE). This enzyme
hydrolyzes ACh into choline and acetate. AChE is located in close proximity to the synaptic cleft
What will cause the release of Ach from vesicles? What does it activate?
What are the 3 endogenous catecholamines?
NE,
EPI, and dopamine
What does catecholamine synthesis terminate with in peripherala postganglionic sympathetic neurons?
In some neurons, including select peripheral posganglionic sympathetic neurons,
cathecolamine synthesis terminates with dopamine
What is the terminal enzymatic step in catecholamine synthesis?
The conversion of dopamine to NE is the terminal enzymatic step in catecholamine
synthesis in postganglionic SNS neurons and in some CNS neurons
What are the 2 physiologic processes that regulate the amount of catecholamine in cytoplasm?
- Inactivation by the neuronal mitochondrial enzyme monoamine
oxidase (MAO) - Transportation of NE into granules by the vesicular monoamine
transporter
What is secreted by the chromaffin cells of the adrenal medulla?
The chromaffin cells of the adrenal medulla synthesize and release EPI and NE EPI (~ 80%; NE ~20%) is the primary catecholamine released from the adrenal medulla
What percentage of catecholamines being released from adrenal medulla is Epinephrine?
~ 80%
What percentage of catecholamines being released from adrenal medulla is norepinephrine?
~20%
What is the process of releasing neurotransmitters from granules contained in adrenergic nerve endings initated by?
arrival of action potential. Calcium dependent.
What can also activate presynaptic adrenergic receptors located on the postganglionic nerve terminal
from which the catecholamine was released?
Norepinephrine.
What are the primary presynaptoc receptors that mediate autoregulatory response to inhibit transmitter release at selected postganglionic SNS nerve terminals?
α 2-adrenergic receptors are the primary presynaptic receptors that, when activated, mediate an autoregulatory response to inhibit transmitter release at selected postganglionic SNS nerve terminals.
What can the release of norepinephrine from post ganglionic SNS neurons be augmented by ?
The release of NE from postganglionic SNS neurons can be augmented by activation of presynaptic
β 2 -adrenergic receptors
What are the 3 physiologic processes that elimate Synaptic NE or terminate NE sympathetic activity?
- Metabolism by the enzyme cathecol-O-methyltransferase (COMT)
- Transported back into postganglionic sympathetic nerve terminals by an active** NE transporter (NET)**
- NE can diffuse away from the synaptic cleft and be metabolized in the plasma or liver, or excreted in the urine
What protiens makes sure that neurotransmitter vesicle can fuse to membrane?
VAMP and SNAP makes sure that NT vesicle can fuse with membrane.
What are the nicotinic and muscarinic chollinergic receptors named after?
These receptors were named according to the alkaloids nicotine and muscarine that were identified to be agonists at the respective receptors
Where are nicotinic receptor located in autonomic ganglia? adrenal medulla? What is their function? Where else are they present?
What are nicotinic muscle receptors involved in? Which nervous system are they involved with? What do they contain/ how are they accesed?
Nicotinic muscle (N
M
) receptors are involved in the signal transmission at the neuromuscular
junction (somatic nervous system) *N N
receptors are ligand-gated ion channels and contain five homologous subunits
* Activation of these receptors initiates a rapid increase in cellular permeability to selective
cations (Na+ and Ca2+):
What is the result of activation of nicotinic receptors?
- Cell membrane depolarization
- Excitation of postganglionic ANS neurons
- Excitation adrenal medullary chromaffin cells
- Excitation of skeletal muscle fibers
Where are muscurinic recceptors located most commonly? what are they innervated by? What are the subtypes? What kind of receptor are they? What is the result of g protien mediated effect?
What receptor is norepinephrine an agonist for? What about dopamine?
The endogenous catecholamines NE and EPI are agonists at α, β-adrenergic receptors (also termed adrenoceptors), whereas dopamine, the metabolic precursor of NE, is a primary agonist at dopaminergic receptors
What are the different a- adrenergic receptors?
There are two types of α-adrenergic receptors: α 1 and α2
Each type contains specific receptors
subtypes: α 1A, α 1B, α,1D ; and α 2A ,α 2B , and α 2C
What are the 3 types of Beta adrenergiv receptors? What about dopaminergic?
There are three primary types of β-adrenergic receptors: β 1 ,β 2
, and β 3
* There are five types of dopaminergic receptors: D1 ,D2, D3, D4, and D5
What kind of receptors are adrenergic receptors?
a.) ligand gated
b.) electronegative
c.) G protein coupled receptors
d.) passive transport
C
What receptor would need to be activated to cause pupillary dialation of the radial muscle?
a1
What receptor would need to be activated to cause pupillary constriction of the sphincter muscle?
M3, M2
What receptor activation would cause slight relaxation of the cilliary muscle?
B2
What receptor activation would cause slight contraction of the cilliary muscle?
M3,M2
Which would cause more stimulating of the lacrimal gland? Stimulation of a1 receptors or muscarinic receptors?
both increase secretion but M3, M2 increase it the most
Which would cause more stimulating of the salivary gland? Stimulation of a1 receptors or muscarinic receptors?
both increase secretion but M3, M2 increase it the most
What receptor stimualtion would cause bronchiolar dialation of bronchiolar smooth muscle?
B2
What receptor stimualtion would cause bronchiolar contraction of bronchiolar smooth muscle?
M2 = M3
In the heart, activation of what receptor for the SA node would cause the highest increase in heart rate?
a.) B1
b.) B2
C.) a1
d.) B3
A
B1 > B2
In the heart, activation of what receptor for the atria would cause the highest increase contractility/ conduction?
a.) B1
b.) B2
C.) a1
d.) B3
A
B1 > B2
In the heart, activation of what receptor for the AV node would cause the highest increase automaticity and conduction?
a.) B1
b.) B2
C.) a1
d.) B3
A
B1 > B2
In the heart, activation of what receptor for the Ventricle would cause the highest increase contractility and conduction?
a.) B2
b.) B1
C.) a1
d.) B3
B
B1> B2
In the heart, activation of what receptor for the SA node would cause the largest decrease in heart rate?
a.) B1
b.) M2
C.) a1
d.) M3
B
M2» M3
In the heart, activation of what receptor for the atria would cause the largest decrease in contractality and conduction?
a.) B1
b.) M2
C.) a1
d.) M3
B
M2»_space; M3
In the heart, activation of what receptor for the AV valve would cause the largest decrease in heart conduction?
a.) B1
b.) M3
C.) a1
d.) M2
D
M2»_space;M3
In the heart, activation of what receptor for the ventricle would cause the largest decrease in heart contractility?
a.) B1
b.) M2
C.) a1
d.) M3
B
M2»_space; M3
If I needed to rapidly increase a patients heart rate, what receptor should I try to effect in order to acheive my desired results?
B1
A 12 year old feline patient who comes acutely dyspneic and has a history of asthma? What receptor would I most likely want to influence with my drug choice to help the patients breathing improve?
a.) M2
b.) M2 or M3
c.) M3
d.) B2
D
What receptor(s) would be responsible for constriction of the arteries/ arterioles?
A1 or a2
What receptor(s) would be responsible for the dialation of arteries/ arterioles?
B2
What receptors can cause a decrease in motility in the digestive tract?
a1,a2,b1,b2
What receptors can cause a increase in motility in the digestive tract?
M2 = M3
What receptors can cause a increase in sphincter tone in the digestive tract?
A1
What receptors can cause a decrease in sphincter tone in the digestive tract?
M3, M2
What receptor causes an inhibition of gastric secretions? Is it sympathetic or parasympathetic innervation?
Sympathetic
A1
What receptor causes an stimulation of gastric secretions? Is it sympathetic or parasympathetic innervation?
M3, M2
Parasympathetic
What receptor causes relaxation of the detrusor muscle of the Urinary bladder? Contraction?
B2- Relaxation
M3 > M2 Contraction
What receptor causes relaxation of the sphincters of the Urinary bladder? Contraction?
a1 contraction
M3> M2 Relaxation
What receptor is responsible for the secretion of epinephrine?
Nicotinic (NN)
What receptor is responsible for the increased secretion of renin?
B1
What receptor is reponsible for inacting glycogenolysis?
a1
What receptor is reponsible for inacting gluconeognesis?
B2
