Ch. 11 Review: Autonomic and Motor Systems
Sympathetic preganglionic neurons exit the spinal nerve via the ___ before they enter the ___.
white ramus; ganglion of the sympathetic trunk
Which is NOT a visceral reflex?
withdrawal reflex
What class of adrenergic receptor activates the enzyme adenylate cyclase?
beta1, beta2, and beta3
Adrenergic receptors with the greatest affinity for epinephrine are ___ receptors.
beta2
Compared to norepinephrine, epinephrine has a greater affinity for what type of receptor?
beta2
Active at rest.
both sympathetic and parasympathetic nervous systems
Releases acetylcholine from its preganglionic fibers.
both sympathetic and parasympathetic nervous systems
Dual innervation of organs by the autonomic nervous system refers to the observation that ___.
both sympathetic and parasympathetic neurons innervate most organs
At rest, what is the relative contribution of the sympathetic and parasympathetic nervous systems to the regulation of homeostasis?
both systems are active but the parasympathetic predominates
When the body is stressed, what is the relative contribution of the sympathetic and parasympathetic nervous systems to the regulation of homeostasis?
both systems are active but the sympathetic predominates
Where are most of the autonomic nervous system control centers located?
brainstem
Where in the central nervous system do the preganglionic neurons of the parasympathetic nervous system originate?
brainstem and sacral region of the spinal cord
Which of the following physiological responses are associated with an elevation in parasympathetic nervous system activity?
enhanced absorption of nutrients
In what class of neuron and within what organelle is the enzyme monoamine oxidase located?
mitochondria of sympathetic postganglionic neurons
Mismatches between vestibular, visual, and proprioceptive sensory inputs activates the autonomic nervous system, leading to symptoms that are characteristic of ___.
motion sickness
The region of skeletal muscle underlying the terminal bouton of a motor neuron is called the ___.
motor end plate
Where on skeletal muscle is the highest density of nicotinic receptors?
motor end plate
Binding of acetylcholine to ___ receptors will activate a G protein.
muscarinic
What cholinergic receptors are coupled to G proteins?
muscarinic
Which class of autonomic nervous system receptors is inotropic?
nicotinic cholinergic
Binding of acetylcholine to ___ receptors causes a ___ by opening channels that permit both sodium and potassium to permeate the membrane.
nicotinic; depolarization
Released from varicosities in the sympathetic nervous system.
norepinephrine
Which contributes to the ability of the sympathetic nervous system to produce widespread responses within the body?
one preganglionic neuron sends collaterals to multiple ganglia, affecting multiple postganglionic neurons
Ganglia are located in or near the effector organ.
parasympathetic nervous system
Preganglionic fibers originate in the brainstem.
parasympathetic nervous system
Releases acetylcholine from its postganglionic fibers.
parasympathetic nervous system
Which is TRUE for the parasympathetic nervous system, but NOT the sympathetic nervous system?
postganglionic fibers release acetylcholine
The somatic nervous system regulates the activity of ___.
skeletal muscle
The autonomic nervous system innervates all the following effector organs and tissues except ___.
skeletal muscles
Preganglionic axons are short, traveling from central nervous system to a chain of ganglia.
sympathetic nervous system
Releases norepinephrine.
sympathetic nervous system
Which neurons of the efferent branch of the peripheral nervous system does NOT release acetylcholine?
sympathetic postganglionic neuron
The balance between sympathetic and parasympathetic activity is modified primarily by ___.
the activity of the body
The steps of synaptic transmission at the motor end plate are below, list the correct order.
7621534 (binds, released, depolarize, action potential, channels open, voltage, terminal)
Which are indicative of the relative release of catecholamines from the adrenal medulla?
80% epinephrine; 20% norepinephrine
The gray ramus is comprised of what fiber type?
C
A motor unit consists of a skeletal muscle fiber (cell) and all of the motor neurons that innervate that skeletal muscle fiber.
False
All autonomic nerves contain only efferent fibers.
False
Atropine, first derived from the Atropa belladonna plant, is a nicotinic receptor antagonist.
False
Binding of a ligand to the alpha1 adrenergic receptor activates Gi; thereby inhibiting the synthesis of cAMP.
False
Physiological stressors will cause parasympathetic nervous system activity to increase.
False
The primary hormone released from the adrenal medulla is norepinephrine.
False
The somatic nervous system provides both excitatory and inhibitory signals to skeletal muscle.
False
According to the theory of dual innervation, the two branches of the autonomic nervous system innervate the same effector organs, but tend to have opposite effects on those organs.
True
Acetylcholine binding to nicotinic cholinergic receptors always excites the postsynaptic cell.
True
Alpha adrenergic receptors have a greater affinity for norepinephrine than for epinephrine.
True
Some visceral reflexes are spinal reflexes.
True
Sympathetic preganglionic neurons traveling to collateral ganglia travel through ganglia of the sympathetic trunk without making synaptic communication.
True
The autonomic nervous system consists of efferent pathways with two peripheral neurons that travel in series from the central nervous system to the effector organ.
True
The autonomic nervous system is also known as the involuntary nervous system.
True
The most abundant neurotransmitter in the peripheral nervous system is acetylcholine.
True
The parasympathetic nervous system exerts more discrete effects on effector organs than the sympathetic nervous system due to the independence of parasympathetic ganglia.
True
The preganglionic neurons of the sympathetic nervous system originate in the spinal cord from a region of gray matter called the intermediolateral cell column.
True
Which of the following cranial nerves does NOT include parasympathetic nerves?
V - trigeminal nerve
What are swellings of postganglionic autonomic axons from which neurotransmitters are released called?
Varicosities
Parasympathetic neurons from which cranial nerve innervate most of the viscera in the thoracic and abdominal cavities?
X
With respect to their innervation, individual skeletal muscle fibers (cells) are innervated by ___.
a single motor neuron
Released from motor neurons.
acetylcholine
Released from sympathetic preganglionics.
acetylcholine
Released from varicosities in the parasympathetic nervous system.
acetylcholine
What is the neurotransmitter released from motor neurons?
acetylcholine
Parasympathetic preganglionic neurons release the neurotransmitter ___; sympathetic preganglionic neurons release the neurotransmitter ___.
acetylcholine; acetylcholine
parasympathetic postganglionic neurons release the neurotransmitter ____; sympathetic postganglionic neurons release the neurotransmitter ___.
acetylcholine; norepinephrine
What enzyme degrades the neurotransmitter released from varicosities of parasympathetic postganglionic neurons?
acetylcholinesterase
Which is located between the invaginations of the motor end plate of a neuromuscular junction?
acetylcholinesterase
Which endocrine glands is innervated by sympathetic preganglionic neurons?
adrenal medulla
Binding of norepinephrine to what type of receptor will trigger the activation of phospholipase C?
alpha 1
Activation of which class of adrenergic receptor will result in calcium release from intracellular stores?
alpha1 only
Actions at which class of adrenergic receptor generally have excitatory effects?
alpha1, alpha2, beta1, and beta3
Activation of which class of adrenergic receptor decreases the cytosolic levels of cAMP?
alpha2 only
What branch of the nervous system is considered the involuntary nervous system?
autonomic nervous system
What type of receptor agonists are used to treat people suffering from asthma or nasal congestion?
beta 2
Name the sympathetic collateral ganglia.
celiac, superior mesenteric, and inferior mesenteric
Which of the regions of the brain is NOT involved in the control of the autonomic nervous system?
cerebellum
What cells of the adrenal medulla release epinephrine?
chromatin cells
Which of the descriptions of collateral ganglia is true?
collateral ganglia are in the sympathetic nervous system but distinct from the sympathetic chain, and they function as a site of communication between sympathetic preganglionic neurons and postganglionic neurons
Parasympathetic preganglionic neurons travel in what nerves?
cranial and pelvic nerves
The cranial nerve that innervated most of the viscera in the thoracic and abdominal cavities is the ___.
cranial nerve X or vagus nerve
The parasympathetic nervous system is also called the ___ division of the autonomic nervous system.
craniosacral
The opening of a cation channel that allows both Na+ and K+ to move through will cause the membrane to ___ because of the ___.
depolarize; greater Na+ electrochemical gradient as compared with K+
Which does NOT have nicotinic cholinergic receptors?
effector organs for the parasympathetic nervous system
The change in membrane potential that occurs in skeletal muscle cells in response to acetylcholine binding to its receptors is called an ___.
end-plate potential
What is the graded change in membrane potential that occurs at the motor end plate of skeletal muscle called?
end-plate potential
The sympathetic nervous system mediates the ___ response as a consequence of its ability to prepare the body to cope with threatening situations.
fight-or-flight
Adrenergic neurotransmitters bind to both alpha (1&2) and beta (1&2) receptors with different affinities. Outline the affinities of these receptors for adrenergic neurotransmitters and characterize their activity as excitatory or inhibitory.
greater affinity for norepinephrine alpha -excitatory; greater affinity for epinephrine beta2 - inhibitory; equal beta 1,3 - excitatory
What area of the brain initiates the fight-or-flight response by producing widespread activation of the sympathetic nervous system?
hypothalamus
Which of the following physiological responses are associated with elevated sympathetic nervous system activity?
increased contractile force of the heart
Within the autonomic ganglia, what are the cells that modulate the flow of information to the target organ called?
intrinsic neurons
How does latroxin, the venom of the black widow spider, cause muscle spasms and rigidity.
it stimulates acetylcholine release from motor neurons
Cells of the adrenal ___ that release epinephrine are called ___.
medulla; chromaffin cells
Which structures of an autonomic neuron is NOT located within the ganglion?
the cell body of preganglionic neurons
Which is TRUE of communication across the neuromuscular junction?
the end-plate potential is always of sufficient magnitude to depolarize the muscle cell to threshold to initiate an action potential
Where do the preganglionic neurons of the sympathetic nervous system emerge from the spinal cord?
thoracic and lumbar regions
The sympathetic nervous system is also called the ___ division of the autonomic nervous system.
thoracolumbar
Which best describes the general arrangement of the efferent limb of the autonomic nervous system?
two neurons in series
Postganglionic neurons of the autonomic nervous system release neurotransmitter from ___.
varicosities
Sympathetic preganglionic neurons exit the spinal cord via the ___, and then join the spinal nerve. They leave the spinal nerve and enter the ganglion via the ___ ramus. Most of the postganglionic fibers return to the spinal nerve via the ___ ramus.
ventral; white; gray
Autonomic reflexes are also called ___ reflexes.
visceral
What type of channels that are present within the varicosities of autonomic neurons are absent from the axon-terminal of other neurons?
voltage gated Na+ and K+ channels
The presence of ___ within varicosities mediate the release of neurotransmitter.
voltage-gated Ca2+ channels
