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Neuro Test 3
2/17 Autonomic
75
Dentistry
Graduate
02/21/2014

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Term
The autonomic nervous system is distinct from the somatic system which controls ________ muscles.
Definition
skeletal
Term
The autonomic nervous system works in concert with the endocrine system and other organ systems to maintain ___________.
Definition
homeostasis-the constancy of the internal environment
Term
True or false:

One of the main roles of the ANS is to provide sensory input from organ systems
Definition
False

One of the main roles of the ANS is to provide motor outflow to organ systems
Term
What are the 2 divisions of the ANS?

What are the 2 levels of organization of the 2 divisions?
Definition
The sympathetic division
The parasympathetic division

the preganglionic and postganglionic neurons
Term
True or false

The parasympathetic and sympathetic ANS innervate the same organs most of the time. However, the effects of activation of the sympathetic pathway are typically opposite to those that result from activation of the parasympathetic pathway
Definition
true
Term
The thoracolumbar system is sympathetic or parasympathetic?
Definition
sympathetic
Term
Which cell column do the preganglionic neurons of the sympathetic system lie in the spinal cord?
Definition
intermediolateral cell column in the spinal cord between the 1st thoracic (T1) and 3rd lumbar segment (L3).
Term
True or False:

Axons from preganglionic neurons exit the cord via the contralateral ventral spinal nerve of that segment and synapse on the “ganglionic” neurons in the sympathetic ganglia
Definition
False

Axons from preganglionic neurons exit the cord via the IPSILATERAL ventral spinal nerve of that segment and synapse on the “ganglionic” neurons in the sympathetic ganglia
Term
Which lies close to the spinal cord? pre vertebral ganglia or paravertebral ganglia

Which lies further away?
Definition
The ganglia that lie close to the spinal cord are the paravertebral ganglia, while other ganglia, the prevertebral ganglia, lie further away.
Term
Where do the sympathetic motor neurons receive sensory input from?
Definition
peripheral targets
Term
Where do the sensory neuron cell bodies lie?
Definition
in the dorsal root ganglia
Term
True or false

Sensory neuron cell bodies send processes both into the periphery and into the spinal cord through the dorsal root
Definition
True
Term
Visceral sensory neurons located in the dorsal root ganglia transmit information from innervated visceral organs to interneurons in the spinal cord to complete autonomic _________ at the spinal level
Definition
reflex arcs
Term
True or false

preganglionic axons of the sympathetic system can be myelinated or unmyelinated
Definition
true
Term
What are the different routes that the preganglionic axons of the sympathetic system can take?
Definition
can project to the paravertebral ganglion associated with the segment

to neighboring paravertebral ganglia through the sympathetic chain

to postganglionic neurons located distally in the pre vertebral ganglia

through one of the autonomic nerves (splanchnic nerve)
Term
Will you find sympathetic preganglionic neurons for the head more rostrally or caudally?
Definition
rostally

sympathetic preganglionic neurons are organized “viscerotopically” so that innervation of structures in the head originate rostrally, while output to the GI tract and other organs are most caudal
Term
What structure is considered to be a modified sympathetic ganglion that functions as an an endocrine organ and releases epinephrine into the blood stream as well as other molecules.?
Definition
adrenal medulla
Term
True or false:

The pre vertebral ganglia and each associated plexus are named after the artery with which they are associated.
Definition
True
Term
Is the craniosacral division sympathetic or parasympathetic?
Definition
parasympathetic
Term
Where are the preganglionic neurons of the parasympathetic system found?
Definition
nuclei in the brainstem and the sacral spinal cord
Term
Where are the parasympathetic ganglia found?
Definition
close to or within the target tissue
Term
True or false:

parasympathetic preganglionic neurons are short and travel along predictable routes
Definition
False

parasympathetic preganglionic neurons are very long and travel along predictable routes
Term
Clusters of parasympathetic neurons in the organs themselves are called ________, because they are less tightly packed than sympathetic ganglia
Definition
plexuses
Term
Sympathetic or parasympathetic?

The cells receive input from sensory neurons within the organ itself.
Definition
parasympathetic

(sympathetic motor neurons receive sensory input from peripheral targets)
Term
Somatic or autonomic?

motor neurons of the spinal cord or cranial nerve nuclei project directly to muscles to form neuromuscular junctions
Definition
somatic (striated muscle)
Term
somatic or autonomic?

motor neurons in the central nervous system project to peripheral postganglionic neurons that in turn innervate muscles
Definition
autonomic (smooth muscle)
Term
True or false:

cranial nerve nuclei are clusters of sympathetic preganglionic neurons
Definition
False

cranial nerve nuclei are clusters of PARASYMPATHETIC preganglionic neurons
Term
True or false:

some cranial nerve nuclei of the parasympathetic systems generate motor commands out, others receive sensory input and others are mixed
Definition
true
Term
What is the most extensive parasympathetic system circuit that projects to the viscera of the thorax
Definition
vagal motor pathways
Term
Visceral and somatic afferents consist of different populations of dorsal root ganglion neurons which project to which laminas of the dorsal horn of the spinal cord?
Definition
I and V
Term
True or false:

The visceral and somatic afferents follow different trajectories and end in different distributions and densities within the spinal cord.
Definition
False

The visceral and somatic afferents follow SIMILAR trajectories and end in different distributions and densities within the spinal cord. (visceral more anteriolateral cell column)
Term
True or false:

The enteric nervous system is only slightly innervated
Definition
False

The enteric nervous system is comprised of extensive networks (plexuses) of ganglia (gets input from sympathetic and parasympathetic)
Term
What is the plexus located between the longitudinal and circular muscle layers of the enteric wall?
Definition
myenteric or Auerbach’s plexus (a dense network)
Term
What is the plexus located in the circular muscle layer and the inner mucosal layer?
Definition
the submucosal or Meissner’s plexus
Term
Besides the auerbach's and meissner's plexuses, what are other plexuses located in the enteric system?
Definition
deep muscular plexus, periglandular plexus, and villous plexus
Term
True or false

The autonomic ganglia are tight cell bodies.
Definition
False

We tend to think of autonomic ganglia being tight cells bodies, but in reality they can be quite loosely packed and extend over a large area.
Term
The autonomic and enteric nervous systems arise from _________ cells.
Definition
neural crest
Term
What type of neural crest cells arise in somites 1-7?
Definition
vagal (neck) NC arises opposite somites 1-7
Term
What type of neural crest cells arise posterior to somite 28?
Definition
sacral
Term
What neural crest cells generate the enteric NS (the gut) and the sacral parasympathetic NS?
Definition
Vagal (neck) NC (arises opposite somites 1-7)
sacral NC (arises posterior to somite 28)

(These neural crest cells migrate down into the developing gut and form the enteric nervous system along with the sacral parasympathetic nervous system. The neural crest cells are found at the tips of the folds as they rise up before they fuse, they migrate down into the developing body to take residence in the tissue.)
Term
What is the condition called due to a failure of neural crest cells to migrate to the colon resulting in absence of enteric ganglia and the absence of peristaltic activity?
Definition
megacolon (a functional obstruction and dilation of the colon and enlargement of the region just above the colon)
Term
True or false:

There are few neurotransmitters/neuromodulators in the enteric nervous system.
Definition
False

Since there are so many pieces to the enteric nervous system, you would expect that the number and diversity of neurotransmitters would be incredible.
Term
Where are the sympathetic system preganglionics for the head and neck (blood vessels, sweat glands, piloerector muscles)?

Where are the ganglionic neurons?

What are the effects that it brings to head and neck (3)?
Definition
upper thoracic spinal cord

superior cervical ganglion

vasoconstriction, piloerection and perspiration.
Term
What results from the sympathetic innervation of the heart (3)?
Definition
increased heart rate
increased stroke volume
dilation of coronary arteries.
Term
The functions of the autonomic system are complex, and many of them are best lumped together by the term “_______________”
Definition
visceral motor functions
Term
Where are the parasympathetic preganglionic neurons for the heart?

Where are the ganglionic neurons?

What is the effect on the heart?
Definition
nucleus ambiguus

cardiac plexus

reduce heart rate
Term
The preganglionic neurons of both sympathetic and parasympathetic systems utilize what neurotransmitter at the synapse with the ganglionic neurons?

What receptors mediate the effect?
Definition
acetylcholine

nicotinic acetylcholine receptors.
Term
What transmitter do the postganglionic fibers of the parasympathetic system release?

What is the receptor that mediates the response?
Definition
acetylcholine

muscarinic receptors
Term
What transmitter do the postganglionic fibers of the sympathetic system release?

What is the receptor that mediates the response?
Definition
norepinephrine

affects several types of receptors
Term
True or false:

The pharmacology of the autonomic system is complex with neurotransmitter effects mediated by many receptor subtypes.
Definition
True
Term
Adrenergic alpha one receptors as found in the eye, bladder, etc will cause contraction of the smooth muscle in some tissues and relaxation of smooth muscle in others when exposed to what transmitter?
Definition
norepinephrine
Term
Choose the incorrect statement:

a) ATP is made from adenosine
b) ATP is packed into either large dense core or small synaptic type vesicles
c) ATP is always released by itself
d) After release, ATPase and other enzymes break it down
e) When ATP is broken down, adenosine can be taken up again
Definition
c) ATP is always released by itself

(ATP can be released along with another transmitter, or by itself)
Term
Stimulation of a postganglionic sympathetic neuron causes how many phases of contraction of a vascular smooth muscle cell?

What transmitters are involved with these phases?
Definition
3

1) ATP (rapid phase)
2) norepinephrine
3) neuropeptide Y (NPY) (slowest phase)
Term
What neurotransmitter binds to a P2X purinoceptor (a ligand-gated cation channel) on the smooth muscle cell, leading to depolarization, activation of voltage-gated Ca2+ channels, increased [Ca2+]i?

What phase of contraction is this?
Definition
ATP

rapid phase (first phase)
Term
What neurotransmitter binds to an alpha 1-adrenergic receptor, which, via a Gq/PLC/IP3 cascade, leads to Ca2+ release from internal stores?

What phase of contraction is this?
Definition
norepinephrine

second phase
Term
What receptor binds to a Y1 receptor and somehow causes an increase in [Ca2+]?

What phase of contraction is this?
Definition
NPY

slowest phase (3rd phase)
Term
What is the unusual neurotransmitter made from L-arginine and a cofactor, citrullline?
Definition
Nitric oxide (by the enzyme nitric oxide synthase)
Term
True or false:

Nitric oxide, like other neurotransmitters, is released at a synapse.
Definition
False

It is a gas so it can diffuse across membranes and does not need to be released at a synapse.
Term
Stimulation of a postganglionic parasympathetic neuron on vascular smooth muscle cell involves what two neurotransmitters in the first phase?
Definition
nitric oxide (NO) and acetylcholine
Term
In postganglionic parasympathetic, the neuron releases _______, which diffuses to the smooth muscle cell.
Definition
nitric oxide
Term
In postganglionic parasympathetic, ____________ binds to M3 muscarinic receptors(G-protein linked) on endothelial cells, leading to the production of more nitric oxide, which also diffuses to the smooth muscle cell.
Definition
acetylcholine
Term
In postganglionic parasympathetic, nitric oxide raises the concentration of ________ in smooth muscle cells.
Definition
cGMP (nitric oxide increases activity go gaunylyl cyclase which makes cGMP)
Term
Does cGMP contract or relaxes muscles?
Definition
relaxes (parasympathetic)
Term
In the second phase of the postganglionic parasympathetic, which tends to occur more with prolonged or intense stimulation, the neuropeptide _______ (or a related peptide) binds to receptors on the smooth muscle cell and causes a delayed relaxation via an increase in [cAMP]i or a decrease in [Ca2+ ]i.
Definition
VIP
Term
True or false:

Because of this complexity, the autonomic system has been a target for drugs for specific problems.
Definition
True
Term
Visceral and cutaneous afferents release transmitters from the ________ family
Definition
tachykinin
Term
Peripherally generated action potentials produce a local release of ________ in the affected terminals and in terminals of the peripheral collaterals
Definition
tachykinins (cause neurogenic inflammation)

(also, when action potentials are generated peripherally, they are propagated centrally-up axon, past DRG, and into spinal cord)
Term
True or false:

A central autonomic network coordinates autonomic function.
Definition
True

So control is reflexive, and occurs without the person’s being aware of it
Term
Sensory input from the aortic arch, and carotid sinus, that contains information about cardiac output ( blood pressure, etc.) is sent to the ______, and the circuit activates preganglionic neurons in the ______ spinal cord. These in turn activate ganglionic neurons in the ________ that provide input to the heart.
Definition
Sensory input from the aortic arch, and carotid sinus, that contains information about cardiac output ( blood pressure, etc.) is sent to the BRAIN STEM, and the circuit activates preganglionic neurons in the THORACIC spinal cord. These in turn activate ganglionic neurons in the SYMPATHETIC CHAIN that provide input to the heart
Term
True or false:

The ANS maintains physiological parameters within ideal ranges by feedback loops
Definition
True
Term
Homeostasis is maintained by monitoring ________ and adjusting ANS ______ so that parameters are kept near an internal set point.
Definition
visceral receptors

output
Term
An increase in blood pressure causes a reflex (increase or decrease) in sympathetic input and an (increase or decrease) in parasympathetic input to the heart.
Definition
an increase in BP causes a reflex decrease in sympathetic input and an increase in parasympathetic input to the heart.
Term
True or false:

The ANS can anticipate future needs.
Definition
True

For example when one begins to exercise, sympathetic output increases before metabolic need increases. For example, alveolar ventilation at the beginning of exercise rises rapidly so that blood levels of CO2 actually drop.
Term
True or false:

Information from the viscera usually always reaches the cortex.
Definition
False

Most information from the viscera never reaches the cortex and we are usually unaware of the constant activity of the ANS due to local feedback loops in the organs themselves such that sensory information from the organ can modulate autonomic outflow to that organ
Term
The preganglionic neurons of the sympathetic nervous system are found

a) in the intermediolateral cell column in the spinal cord
b) in the dorsal root ganglia
c) in the ventral horn of the spinal cord
d) in the brainstem
Definition
in the intermediolateral cell column in the spinal cord

(Neurons that convey sensory information from the viscera to the spinal cord: project to laminae I and V of the dorsal horn of the spinal cord, AND have their cell bodies in the dorsal root ganglia)
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