ANS Flashcards
Afferent division of the nervous system is composed of ____ information from the ____, the ___, and _____.
The Afferent Division is composed of sensory information from the muscles (somatic sensory); the guts (visceral sensory); and special senses to include vision, hearing, balance, taste and smell.
The efferent division includes the _____ and _____ systems.
Sympathetic and parasympathetic
The ____ division consists of a single neuron between the CNS and skeletal muscle, leading to skeletal muscle innervation and muscle excitation only.
The ____ division has two neuron chains connected by a synapse and innervates smooth and cardiac muscle, GI, and neurons, to which it can be excitatory or inhibitory.
The somatic efferent division consists of a single neuron between the CNS and skeletal muscle, leading to skeletal muscle innervation and muscle excitation only.
The autonomic efferent division has two neuron chains connected by a synapse and innervates smooth and cardiac muscle, GI, and neurons, to which it can be excitatory or inhibitory.
Synapses for somatic motor neurons are at ______
neuromuscular junctions
What’s a ganglion?
Collection of neuronal cell bodies outside the CNS
The postganglionic axon becomes highly branched as it approaches its target. Along the branches are a series of swellings called _______. It is from these that thhe neurotransmitter is released onto the _____.
The postganglionic axon becomes highly branched as it approaches its target. Along the branches are a series of swellings called varicosities. It is from these that thhe neurotransmitter is released onto the target cell.
The parasympathetic division is also referred to as the ______ division because the preganglionic neurons are located in the _____ and in the _____ region of the CNS.
The parasympathetic division is also referred to as the craniosacral division because the preganglionic neurons are located in the brainstem and in the sacral region of the CNS.
Describe the length and location of neurons in the parasympathetic nervous system:
In parasympathetic division,
Preganglionic neurons are in the brainstem and sacral region and have long axons.
The postganglionic neurons have short axons with body in the periphery.
The cell bodies of “cranio” parasympathetic neurons are in the ____ and axons are in the ____.
The cell bodies of “sacro” parasympathetic neurons are in the _____ and axons are in the ____.
The cell bodies of “cranio” parasympathetic neurons are in the brainstem and axons are in the cranial nerves.
The cell bodies of “sacro” parasympathetic neurons are in the sacral spinal cord and axons are in the peripheral nerves.
The sympathetic division is also called the _____ division because of the location of the preganglionic cell bodies.
The sympathetic division is also called the thoracolumbar division because of the location of the preganglionic cell bodies.
The preganglionic neuron in the sympathetic division has a cell body located in the ______ of the spinal cord. The axon exits via _____ and heads for the sympathetic chain _____, called the ________.
The preganglionic neuron in the sympathetic division has a cell body located in the intermediolateral column of the spinal cord. The axon exits via ventral roots and heads for the sympathetic chain ganglia, called the sympathetic trunk.
Describe key sympathetic chain ganglia of the sympathetic division:
•Cervical Ganglia:
- Superior
- Middle
- Inferior
- Ganglia adjacent to thoracic & upper lumbar & sacral segments
- Prevertebral Ganglia:
- Celiac
- Superior Mesenteric
- Inferior Mesenteric
What are chromaffin cells?
Modified postganglionic sympathetic neurons located in the adrenal medulla, regulated by the sympathetic nervous system. These cells secrete EPI and NE into the general circulation, regulating endocrine function.
Paravertebral ganglia are:
A. the location of postganglionic parasympathetic neuron cell bodies.
B. composed of somatic motor neuron cell bodies.
C. the location of postganglionic sympathetic neuron cell bodies.
D. the location of preganglionic sympathetic neuron cell bodies
C. the location of postganglionic sympathetic neuron cell bodies.
The preganglionic parasympathetic neuron releases _____ on ____ receptors.
The postganglionic parasympathetic neuron releases _____ on _____ receptors (located on the effector cell).
The preganglionic parasympathetic neuron releases acetylcholine on nicotinic receptors.
The postganglionic parasympathetic neuron releases acetylcholine on muscarinic receptors (located on the effector cell).
The sympathetic preganglionic neuron releases ____ onto _____ receptors.
The sympathetic postganglionic neuron releases ____ onto ___ receptors (on the effector cell).
The sympathetic preganglionic neuron releases Acetylcholine onto nicotinic receptors.
The sympathetic postganglionic neuron releases norepinephrine onto adrenergic receptors (on the effector cell).
nicotinic receptors are examples of ______ receptors, while muscarinic and adrenergic receptors are examples of _____ receptors.
nicotinic receptors are examples of ionotropic receptors, while muscarinic and adrenergic receptors are examples of metabotropic receptors.
Muscarinic receptors are located in the plasma membrane of
A. postganglionic parasympathetic neuronal cell bodies
B. parasympathetic effector cells
C. postganglionic sympathetic neuronal cell bodies
D. most sympathetic effector cells
B. parasympathetic effector cells
What are 3 key exceptions to the standard sympathetic pattern of postganglionic neuron release of NE/EPI onto adrenergic receptors?
Sweat glands - even though innervated by sympathetic system, the postganglionic neurons release ACh, which binds to muscarinic receptors.
Dopamine can be released by postganglionic sympathetic neurons, which binds to a dopamine 1 receptor on renal vasculature smooth muscle.
The adrenal medulla is directly innervated by preganglionic sympathetic fibers, which trigger the medulla to release NE and Epi into bloodstream directly (instead of using a neuron), which then binds to alpha and beta adrenergic receptors.
The heart is regulated by ____ and ____ receptors
Beta 1 - stimulates the depolarization of the SA and AV nodes and cardiac myocytes, increasing both chronotropy and inotropy.
M2 - hyperpolarizes these cells, decreasing both chronotropy and inotropy.
In glandular tissues, M3 receptors promote ____, while in smooth muscle tissues M3 promotes _____.
In glandular tissues, M3 receptors promote secretions, while in smooth muscle tissues M3 promotes contraction.
alpha 1 receptors are located on the peripheral ______, and stimulation causes _____.
alpha 1 receptors are located on the peripheral blood vessels, and stimulation causes vasoconstriction.
____ receptors on the SA node cause an increase in heart rate when stimulated.
B1 receptors on the SA node cause an increase in heart rate when stimulated.
_____ receptors cause bronchodilation and vasodilation when stimulated.
B2 receptors cause bronchodilation and vasodilation when stimulated.
Most of the effects of the a2 receptor result from its location on _______ neuron terminals
Most of the effects of the a2 receptor result from its location on presynaptic neuron terminals
a2 receptors have important presynaptic and postsynaptic effects. Explain what each are.
Presynaptically, a2 inhibits the release of NE from the presynaptic neuron (basically serves as a negative feedback loop to block sympathetic signals)
Postsynaptically, a2 induces smooth muscle contraction, just like a1
Are blood vessels innervated by the sympathetic, parasympathetic, both, or neither?
Sympathetic innervates most blood vessels
Parasympathetic innervates most arteries and arterioles, but NOT veins or venules
What is meant by parasympathetic discrete control of effectors?
Discrete control means that each organ can be regulated separately, so we can urinate without having our heart rate drop significantly.
The sympathetic nervous system is capable of mass ______, meaning what?
Capable of mass discharge
Activation of multiple organ systems concurrently
Epocrine sweat glands:
located all over body, function for thermoregulation, postganglionic neurons release ACh; binds to muscarinic receptors on sweat gland target.
Appocrine sweat glands:
located in armpits, genitals, perianal; active from puberty onward; adrenergic receptors on sweat gland, may be regulated hormonally (epinephrine in blood stream)
What targets are ONLY innervated by the sympathetic nervous system (and not parasympathetic)?
Sweat glands
Pilomotor muscles of the skin
Arterioles
Veins
Increased parasympathetic activity promotes ______ of airways.
Constriction
(also causes increased bronchial secretions)
Describe the sexual response effects of parasympathetic activity:
Male: erection
Female: increased blood flow, lubrication
Explain the regulation of the detrussor muscle, internal urethral sphincter, and external urethral sphincter via parasympathetic and sympathetic divisions:
Parasympathetic promotes urination - contracts the detrussor muscle causing urge to urinate.
Sympathetic inhibits micturation.
(somatic is under voluntary control)
Compare the sympathetic vs. parasympathetic affects on salivation:
Sympathetic: stimulation promotes thick, mucousy salivary secretions
Parasympathetic: stimulation promotes watery secretions
Which of the following responses is consistent with a “mass discharge” of sympathetic tone?
A. Pupil dilation; ↑ gastric HCl secretion; constriction of internal urethral sphincter
B. Pupil constriction; ↑ heart rate; erection
C. Pupil dilation; bronchodilation; ejaculation
C. Pupil dilation; bronchodilation; ejaculation
What is a reflex?
Involuntary response to a stimulus - cerebral cortex is not directly involved
What are the 4 main components of the reflex arc?
–Afferent limb = Sensory limb
- Receptor
- Afferent pathway
–Central Integration Center
–Efferent limb = output
- Efferent pathway
–Effector = Target (muscle, gland)
(reflexes can be neuronal or hormonal)
Explain the reflex arc that occurs in the case of e.g. hemorrhage:
Where are baroreceptors located that detect changes in blood pressure and volume?
Aortic arch and carotid sinus
Parasympathetic and sympathetic divisions are organized as a ______ chain
Parasympathetic and sympathetic divisions are organized as a two-neuron chain
_____ is released at both parasympathetic and sympathetic preganglionic neurons. The receptors on the post-ganglionic cell are always _____.
ACh is released at both parasympathetic and sympathetic preganglionic neurons. The receptors on the post-ganglionic cell are always nicotinic.
Parasympathetic postganglionic neurons release ____ from the postganglionic neuron and binds to ____ ____ receptors on the effector tissue.
Parasympathetic postganglionic neurons release ACh from the postganglionic neuron and binds to muscarinic cholinergic receptors on the effector tissue.
Most sympathetic postganglionic neurons release ______ onto their effector tissues. The receptors are _____ receptors.
Most sympathetic postganglionic neurons release norepinephrine onto their effector tissues. The receptors are adrenergic receptors.
The adrenal gland is a modified ____ neuron. It releases ____ and ____.
The adrenal gland is a modified postganglionic neuron. It releases norepinephrine and epinephrine.
Autonomic reflex arcs include the _____ reflex which helps to maintain blood pressure and volume.
Autonomic reflex arcs include the baroreceptor reflex which helps to maintain blood pressure and volume.
Autonomic reflex arcs include the baroreceptor reflex which helps to maintain _____ and ______.
Autonomic reflex arcs include the baroreceptor reflex which helps to maintain blood pressure and volume.
The ANS regulates the function of involuntary muscle (smooth and cardiac) and _____
glands
Label as sympathetic and parasympathetic
Which receptors are GPCRs - parasympathetic, sympathetic, both, or neither?
Both.
What organs have M2 vs. M3 receptors?
M2 - HEART!!!!!
M3 - eye, salivary glands, lungs, stomach, bladder
What adrenergic receptor(s) are located on the eye?
a1 and B2
What adrenergic receptor(s) control the salivary glands?
B2
What adrenergic receptor(s) control the stomach?
B2
What adrenergic receptor(s) control the bladder?
a1 and B2
What organs are controlled via B2 receptors?
Eyes
Salivary glands
Lungs
Stomach
Bladder
What organs are controlled via a1 receptors?
Eye
Bladder
(both are also controlled via B2 and M3 receptors)
What receptors (adrenergic and cholinergic) control the eye?
M3 (cholinergic)
a1 and B2 (adrenergic)
What receptors (adrenergic and cholinergic) control the salivary glands?
M3 (cholinergic)
B2 (adrenergic)
What receptors (adrenergic and cholinergic) control the lungs?
M3 (cholinergic)
B2 (adrenergic)
What receptors (adrenergic and cholinergic) control the stomach?
M3
B2
What receptors (adrenergic and cholinergic) control the bladder?
M3
a1
B2
The ___ receptor inhibits the SA/AV node and cardiac muscle
M2
The M3 receptor promotes ____ and ____.
Secretion
Smooth muscle contraction
Which adrenergic receptor promotes smooth muscle contraction?
a1 (and somewhat a2)
Which receptor stimulates the SA/AV node and cardiac muscle?
B1 receptors
Stimulation of which receptor promotes smooth muscle relaxation?
B2 receptors
Which adrenergic/cholinergic receptors are Gq type GPCRs, and what are their signaling pathways?
M3 and a1
Gq –> PLC –> Ca++
Which adrenergic/cholinergic receptors are Gi type GPCRs, and what are their signaling pathways?
M2 and a2
Gi –> AC –> cAMP
Which adrenergic/cholinergic receptors are Gs type GPCRs, and what are their signaling pathways?
B1 and B2
Gs –> AC –> cAMP
Are toxicities more common with parasympathetic or sympathetic drugs?
Parasympathetic
Most PS drugs are non-selective (vs. sympathetic drugs are selective).
Route of administration of PS drugs is important
How do M2 and B1 receptors regulate heart rate?
M2 agonists _____ cardiac output.
M2 antagonists ____ cardiac output.
M2 agonists reduce cardiac output.
M2 antagonists increase cardiac output.
Atropine is a ___ ___ (receptor type, agonist/antagonist).
What is its ultimate effect?
Atropine is an M2 antagonist
Ultimately increases cardiac output and elevates heart rate (also used to reverse cholinesterase poisoning)
B1 agonists _____ cardiac output.
B1 antagonists ____ cardiac output.
B1 agonists increase cardiac output.
B1 antagonists decrease cardiac output.
Metoprolol, Carvedilol, and Nadolol are B1 ______ thus they ____ cardiac output.
Metoprolol, Carvedilol, and Nadolol are B1 antagonists thus they decrease cardiac output.
Dobutamine and Isoproterenol are B1 ____ thus they ____ cardiac output.
Dobutamine and Isoproterenol are B1 agonists thus they increase cardiac output.
In the lungs, stimulation of ___ receptors promotes bronchoconstriction while stimulation of ___ receptors promotes bronchodilation.
In the lungs, stimulation of M3 receptors promotes bronchoconstriction while stimulation of B2 receptors promotes bronchodilation.
Methacholine is an M3 _____, meaning it promotes broncho_____.
Methacholine is an M3 agonist, meaning it promotes bronchoconstriction.
Ipratropium, Tiotropium, Glycopyrrolate, Aclidinium, and Umeclidinium are M3 ______, thus they promote broncho____.
Ipratropium, Tiotropium, Glycopyrrolate, Aclidinium, and Umeclidinium are M3 antagonists, thus they promote bronchodilation.
Albuterol, Salmeterol, Formoterol, Indacaterol, and Epinephrine are B2 ____, thus they promote broncho_____.
Albuterol, Salmeterol, Formoterol, Indacaterol, and Epinephrine are B2 agonists, thus they promote bronchodilation.
The detrussor muscle of the bladder is controlled via ____ receptors that promote detrussor contraction and ____ receptors that promote detrussor relaxation.
The detrussor muscle of the bladder is controlled via M3 receptors that promote detrussor contraction and B2 receptors that promote detrussor relaxation.
(also controlled by a1 receptors - promotes urethral contraction)
Bethanachol is an M3 ____, thus causes urinary ____.
Bethanachol is an M3 agonist, thus causes urinary urgency.
Oxybutynin, Solifenacin, and Tolterodine are M3 ______, thus promote urinary ______.
Oxybutynin, Solifenacin, and Tolterodine are M3 antagonists, thus promote urinary retention.
Terazosin, Doxazosin, and Tamsulosin are a1 ______, thus promote urinary _____.
Terazosin, Doxazosin, and Tamsulosin are a1 antagonists, thus promote urinary urgency.
Tamsulosin is used to treat BPH, which causes an enlarged prostate blocking urine flow.
GI tract stimulation of M3 receptors promotes GI smooth muscle ______.
GI tract stimulation of B2 receptors promotes GI smooth muscle ______.
GI tract stimulation of M3 receptors promotes GI smooth muscle contraction.
GI tract stimulation of B2 receptors promotes GI smooth muscle relaxation.
Dicyclomine and Hyocyamine are M3 _____, thus they INCREASE/REDUCE peristalsis.
Dicyclomine and Hyocyamine are M3 antagonists, thus they INCREASE/REDUCE peristalsis.
(used to treat IBS)
Stimulation of M3 receptors promotes _____ saliva secretion. Stimulation of B2 receptors promotes ____ saliva secretion.
Stimulation of M3 receptors promotes watery saliva secretion. Stimulation of B2 receptors promotes thick saliva secretion.
Stimulation of ___ receptors promotes watery saliva secretion. Stimulation of ___ receptors promotes thick saliva secretion.
Stimulation of M3 receptors promotes watery saliva secretion. Stimulation of B2 receptors promotes thick saliva secretion.
Pilocarpine is an M3 ____, stimulating ___ saliva production.
Glycopyrrolate is an M3 ____, stimulating ___ saliva production.
Pilocarpine is an M3 agonist, stimulating watery saliva production.
Glycopyrrolate is an M3 antagonist, stimulating thick saliva production.
(Pilocarpine is used for Sjogren’s syndrome)
Stimulation of M3 promotes eye _____, whereas stimulation of a1 promotes eye _____.
Stimulation of M3 promotes eye constriction, whereas stimulation of a1 promotes eye dilation.
Atropine is an M3 ____, so it promotes pupil ____.
Carbachol is an M3 ____, so it promotes pupil ____.
Atropine is an M3 antagonist, so it promotes pupil dilation.
Carbachol is an M3 agonist, so it promotes pupil constriction.
Uterine smooth muscle contraction is regulated by ___ and ___ (cholinergic and/or adrenergic receptors).
Uterine smooth muscle contraction is regulated by M3 and B2.
M3 promotes uterine _____. B2 promotes uterine _____.
M3 promotes uterine contraction. B2 promotes uterine relaxation.
Terbutaline is a B2 ____, and is used to promote uterine ____.
Terbutaline is a B2 agonist, and is used to promote uterine relaxation.
(Given to slow down premature labor)
What receptors regulate vascular constriction?
a1 and B2
NO parasympathetic stimulation
a1 promotes vaso______; B2 promotes vaso_____.
a1 promotes vasoconstriction;
B2 promotes vasodilation.
Midodrine is an a1 ____, thus it promotes vaso_____.
Midodrine is an a1 agonist, thus it promotes vasoconstriction.
Prazosin, Terazosin, and Doxazosin are a1 _____, thus they promote vaso____.
Prazosin, Terazosin, and Doxazosin are a1 antagonists, thus they promote vasodilation.
Sympathetic stimulation causes a positive dromotropic and positive chronotropic effect. What does this mean?
Positive dromotropic effect = increased conduction velocity of action potentials
Positive chronotropic effect = increased heart rate
What is the major effect of sympathetic stimulation of the SA node?
Faster rate of phase 4 depolarization
Parasympathetic stimulation of SA node causes a ___ chronotropic and a ___ dromotropic effect.
Parasympathetic stimulation of SA node causes a negative chronotropic and a negative dromotropic effect.
AKA
decreased HR (negative chronotropic)
decreased conduction velocity (negative dromotropic)
Parasympathetic stimulation increases SA nodal permeability to ___.
Parasympathetic stimulation increases SA nodal permeability to potassium.
(results in hyperpolarization)
Sympathetic stimulation of the SA node increases the open state probability of ___ channels.
Sympathetic stimulation of the SA node increases the open state probability of HCN channels.
(these allow Na entry - causes depolarization. Also increases permeability of T-type and L-type Ca++ channels)
Sympathetic stimulation increases rate of cardiac muscle ____ and ____.
Sympathetic stimulation increases rate of cardiac muscle tension and relaxation.
(increases tension/contraction via increased L-type Ca++ channel (DHP channel) permeability. Increased relaxation by increasing activity of SERCA pumps - this makes the myocyte ready for another depolarization aka contraction sooner)
B. Dobutamine, a beta-1 adrenergic receptor agonist
HR and SV are controlled by ____ receptors.
Vascular tone aka SVR is controlled by ___ receptors (and less so by ___ receptors).
HR and SV are controlled by B1 receptors.
Vascular tone aka SVR is controlled by a1 receptors (and less so by B2 receptors).
a1 receptors promote vasoconstriction and B2 receptors promote vasodilation.
List two important synthetic B agonists and two important endogenous B agonists:
Synthetic:
- Dobutamine (B1 > B2)
- Isoproterenol (B1 & B2)
Endogenous:
- Norepinephrine
- Epinephrine
What is the most important difference between EPI and NE?
The low affinity of NE for the B2-AR.
Otherwise, both have a very similar affinity for B1 and a1/a2 receptors.
A. Metoprolol, a beta-1 adrenergic receptor antagonist
The primary effect of B1-AR stimulation in SA nodal cells is to increase the rate of _____ depolarization, which increases _____.
The primary effect of B1-AR stimulation in SA nodal cells is to increase the rate of Phase 4 depolarization, which increases heart rate.
D. Phenylephrine, an alpha-1 adrenergic receptor agonist
(Phenylephrine, like NE, is purely an alpha-1 antagonist)
C. Atropine, a muscarinic (M2) receptor antagonist
