3 Flashcards
(94 cards)
1
Q
General Model of SNS:
A
- Motor output to the sympathetic nervous system descends from the brain OR input from afferents (from the body) synapses on neurons in the intermediolateral cell column (gray matter) - Located from T1 – L3
- SNS neurons send efferent axons through the white rami communicantes to a paravertebral ganglion
- Within the paravertebral ganglion, the axon can:
- Option 1: Synapse within the paravertebral ganglion at that spinal level
- Option 2: Continue to another paravertebral ganglion at a different spinal level and synapse there
- Option 3: Pass through the paravertebral ganglion and continue to a prevertebral ganglion (through a splanchnic nerve) and synapse there
2
Q
Solid lines = efferents from spinal cord to _________
A
1st ganglion
- pre-gangionic fibre
3
Q
Dotted lines = efferents from gangion to ___
A
target organ
- post-ganglionic fibre
4
Q
Where is the intermediolateral horn/column found?
A
Found in lamina VII of the thoracic and upper lumbar spinal cord
5
Q
T/F: The descending pathways that influence neurons in intermediolateral horn/column are diffuse and hard to distinguish
A
True
6
Q
Reflex pathways from afferents also impact the activity of neurons in which column?
A
intermediolateral horn/column
7
Q
Option 1: Neuron in the intermediolateral horn (pre-ganglionic neuron) –> synapses on a neuron in the paravertebral ganglion at that __ spinal level
A
same
8
Q
Option 1: Axon travels through the __ __ __, synapses on the post-ganglionic neuron
A
white rami communicantes
9
Q
T/F: White rami communicantes are myelinated
A
True
10
Q
Option 1: The postganglionic neuron sends efferents out to __ __
A
visceral organs
11
Q
T/F: Gray rami communicantes are myelinated
A
False, unmyelinated
12
Q
Option 1: Gray rami communicantes (unmyelinated fibres) join the __ __
A
spinal nerve
13
Q
What are sympathetic inputs of option 1 of the SNS?
A
- skin, blood vessels, heart, and lungs at that spinal level
14
Q
Option 2: Where do the cervical ganglia recieve fibers from?
A
Upper thoracic intermediolateral horn:
- Superior cervical ganglion – around the level of C1 – C4
- Middle cervical ganglion C5-C6
- Inferior cervical ganglion C7-C8
14
Q
Option 2: Neuron in the intermediolateral horn (pre-ganglionic neuron) –> synapses on a neuron in a paravertebral ganglion at a __ spinal level
A
different
15
Q
Option 2: The inferior cervical ganglion fuses with fibres from the first thoracic ganglion to form the __ __
A
stellate ganglion
16
Q
Option 2: Superior cervical ganglion – SNS input to the __ __
A
cranial nerves
17
Q
Option 2: nerves travel along blood vessels and often join the parasympathetic fibres of __ __
A
cranial nerves
18
Q
Option 2: Which cranial nerves does the superior cervical ganglion house?
A
CNs III, VIII, IX, X
19
Q
Option 2: Middle + stellate – SNS input to:
A
- heart
- trachea, bronchi, bronchioles
20
Q
The __ and __ receive inputs from “Option 1” and “Option 2” gray ramii, forming web-like cardiac and pulmonary plexuses that innervate these structures
A
heart; lungs
21
Q
Option 2: Long ciliary nerves –> SNS input to pupil causing? Accompanies by?
A
- pupillary dilation
- accompany short ciliary nerves (CN III)
22
Q
Option 2: T/F: SNS input tends to make tears, saliva less “watery”, more “mucus-y”
A
True
23
Q
Option 2: The SNS inputs tend to accompany the cranial nerves at some point along their course, which cranial nerves?
A
CN VII, IX
24
Option 3: Neuron in the intermediolateral horn --> passes through the paravertebral ganglion (no synapse) --> synapses on a ___ __
pre-vertebral ganglion
25
Option 3: The __ __ form nerves on the way to the prevertebral ganglion
white ramii
26
Option 3: greater splanchnic nerve --> __ __ (T5 – T9)
celiac ganglion
27
Option 3: lesser splanchnic nerve --> __ __ __, __ __ (T10 – T11)
superior mesenteric ganglia, aorticorenal ganglia
28
least splanchnic nerve --> __ __ (T12)
renal plexus/ganglia
29
lumbar & sacral splanchnic nerves --> __ __ __, plexuses to pelvic and lower abdominal organs (L1 – L2)
inferior mesenteric ganglia
30
Option 3: What is the celiac ganglion responsible for?
pancreas, liver
31
Option 3: What is the aorticorenal ganglia responsible for?
- kidney
- gonad
- suprarenal gland
32
Option 3: What is the superior mesenteric ganglion responsible for?
- ascending colon
- transverse colon
- small intestine
33
Option 3: What is the inferior mesenteric ganglion responsible for?
- descending colon
34
Compare and contrast SNS & PNS
Sympathetic nervous system
- short pre-ganglionic fibres, longer post-ganglionic fibres
- Neuronal cell bodies in the intermediolateral horn of T1 – L3
- Ganglia can be paravertebral or prevertebral
- Pre-ganglionic fibres can be white rami communicantes from the spinal cord or splanchnic nerves
Parasympathetic nervous system
- Long pre-ganglionic fibres, short post-ganglionic fibres
- Neuronal cell bodies in the brainstem (cranial nerve nuclei) or sacral spinal levels
- No prevertebral or postvertebral ganglia
35
T/F: Parasympathetic nervous system is cranial nerve and sympathetic nervous system is spinal nerves (but can combine with cranial nerves)
True
36
Edinger-Westphal nucleus (midbrain) --> ciliary ganglion --> causing pupillary constriction
CN III
37
Superior salvitory nucleus (pons) --> sphenopalatine --> lacrimal gland, nasal mucous secretions
CN VIII
38
superior salivatory nucleus (pons) --> submandibular ganglion --> sublingual, submaxillary salivary glands
CN VIII
39
inferior salivatory nucleus (medulla) --> otic ganglion --> parotid salivary glands
CN IX
40
Salivary & lacrimal secretion is mainly under control of which nervous system?
parasympathetic nervous system control
41
T/F: PNS causes more saliva, more watery, more digestive enzymes
True
42
T/F: SNS causes less fluid, more “sticky”
True
43
What is the cranial nerve responsible for most of parasympathetic nervous output?
vagus
44
What nucleus is associated with the vagus nerve?
dorsal motor nucleus of the vagus
45
What is the pathway of the vagus nerve?
- Longest course of any cranial nerve – leaves through jugular foramen and descends alongside the carotid arteries
- Forms anterior and posterior trunks at the stomach and divides to supply plexuses in the abdominal cavity, all the way to the left (distal) colon
46
Where are the bodies of the parasympathetic sacral efferents found?
S2-S4
47
What do the parasympathetic sacral efferents travel with?
pelvic splanchnic nerves
48
What does the parasympathetic sacral efferent supply?
- rectum
- bladder
- male & female reproductive organs
49
Fill in the blocked out spots
intermediolateral column, T1-L3
pre vertebral & paravertebral
brainstem nuclei & sacral segments
small ganglia in walls of viscera
50
What is the main neuro-transmitter & main receptor of SNS preganglionic?
- acetylcholine
- nicotinic
51
What is the main neuro-transmitter & main receptor of SNS postganglionic?
- norepinpehrine (+ epinphrine in adrenal medulla)
- adrenergic, alpha + beta
52
What is the main neurotransmitter & main receptor of PaNS preganglionic?
- acetylcholine
- nicotinic
53
What is the main neurotransmitter & main receptor of PaNS postganglionic?
- acetylcholine
- muscarinic (acetylcholine)
54
What are exceptions to SNS postganglionic neurotransmission?
- Acetylcholine in skin
- Adrenal glands don’t have post-ganglionic innervation… they “are” the ganglion
55
When is acetylcholine used in SNS postganglionic neurotransmission?
- sweat glands (muscarinic)
56
Where does the parasympathetic nervous system have impact on blood vessels?
- the GI system
- the reproductive system
57
Where is acetylcholine synthesized & stored?
Acetylcholine is synthesized in presynaptic nerve terminals and then stored in vesicles
- Reaction:
Acetyl-CoA + Choline ----------------> Acetylcholine
Enzyme: choline acetyltransferase
58
After acetylcholine is secreted into the synapse it is degraded by what?
acetylcholinesterase
59
What is acetylcholine degraded to?
acetate and choline (choline is taken back up into the presynaptic terminal)
60
Where is acetylcholinesterase distributed?
Acetylcholinesterase is widely distributed in connective tissue throughout the body and in the synapse of cholinergic terminals
61
How is norepinephrine synthesized?
Outside the vesicle:
- Tyrosine ---------------------> Dopa (hydroxylation)
- Dopa -------------------------> Dopamine (decarboxylation)
Then, dopamine is transported into the synaptic vesicle:
- Dopamine -------------------> Norepinephrine (hydroxylation)
In the adrenal medulla, most norepinephrine is converted into epinephrine through methylation (in the vesicle)
- Norepinephrine ------------> Epinephrine (methylation)
62
hormones made by adrenal glands
caetcholamines
63
__-__% of secreted norepinephrine is taken up again into the presynaptic terminal
50 – 80
64
How is epinephrine taken back up?
secreted into the bloodstream by the adrenal medulla (endocrine)
65
__ can be broken down by monoamine oxidase near the synapse and catechol-O-methyl-transferase (COMT)
Norepinephrine
66
67
68
Both the parasympathetic (__) and sympathetic (__) outputs are important for pupillay size
However, focusing the lens is mostly under control of the __ system
constriction; dilation; parasympathetic
69
Nasal, lacrimal, salivary, gastrointestinal glands:
Strongly stimulated by __ activity – lots of watery secretions that are rich in enzymes (when enzymes apply)
Glandular secretion can also be stimulated by the __ – less watery, therefore usually lower rate of secretion
The glands of the intestines are less controlled by the ___, more by the food in the lumen of the gut
parasympathetic; sympathetic; autonomic NS
70
Sweat glands: stimulated by the __ – however, the neurotransmitter secreted is __
sympathetic nervous system; acetylcholine
71
Blood vessels:
__ nervous system – vasoconstriction in most vascular beds – mediated by alpha-1 receptors - Vasodilation in others mediated by __ in skeletal muscles, heart, liver
__ nervous system – very limited effect on any blood vessels outside the GI tract and reproductive organs
Sympathetic; beta-2 receptors; Parasympathetic
72
Heart:
__ nervous system – beta-1 receptors increase contractility (basically, force of contraction) and heart rate --> increased cardiac output
__ – muscarinic receptors decrease heart rate but have a small (negative) influence on contractility
Sympathetic; Parasympathetic
73
Glucose metabolism:
No role for the __ nervous system
Gluconeogenesis, glycogenolysis, hyperglycemia with __ nervous system stimulation
parasympathetic; sympathetic
74
The parasympathetic nervous system usually causes __, __ responses
specific localized
75
The sympathetic nervous system can participate in specific, localized responses as well – the usual day-to-day function of the SNS + overwhelmingly activated (mass discharge) to accomplish the “__ _ __” response
fight or flight
76
Major reflexes include:
Baroreceptor reflex
- __ – baroreceptors from CNs IX and X
- __ – parasympathetic and sympathetic CN X, thoracic plexus
GI reflexes mediated by sensing food (whether sight/taste/smell or presence of food/secretions in the lumen)
- __ – visceral receptors from CN X
- __ – CN X
Micturition (urination) reflex
- afferents & efferents at the level of the __ __ __
afferent; efferent
afferent; efferent
sacral spinal cord
77
__ __ __ in the medulla receives input from the afferents, sends output to a wide variety of other brain areas
Nucleus tractus solitarius
78
Prevention of storage in the NT vesicle
Reserpine – blocks VMAT --> depletion of catecholamines, increase or decrease in catecholamine transmission?
decrease
79
Non-vesicle-mediated “leakage” of neurotransmitter from the presynaptic terminal
Amphetamine, tyramine, increase or decrease in catecholamine transmission?
increase
80
Inhibition of reuptake at the presynaptic terminal
Cocaine, selective norepinephrine reuptake inhibitors (i.e. Effexor)
Increase or decrease in catecholamine transmission?
increase
81
Inhibition of NT degradation
Mono-amine oxidase inhibitors (tranylcypromine)
Increase or decrease in catecholamine transmission?
Increase
82
Inhibition of NT release due to auto-receptor activation
Clonidine thought to be a major example
Increase or decrease in catecholamine transmission?
Decrease
83
a substance that activates a receptor when it binds to it
agonist
84
a substance that binds to a receptor but doesn’t activate it fully
partial agonist
85
a substance that inactivates a receptor or enzyme when it binds to it
antagonist
86
T/F: Antagonist can be reversible & irreversible
True
87
Alpha and beta receptors have different __ for different agonists and antagonists
affinities
88
beta receptors have a high affinity for __, but alpha receptors have a negligible affinity. __ is therefore a selective beta-agonist
isoproterenol
89
Beta-1 receptors have a high affinity for __, but beta-2 receptors don’t. __ is therefore a selective beta-1 antagonist
metoprolol
90
Phenylephrine
- Selective agonist for __ receptors
- Main indication is as an over-the-counter __ - Causes vasoconstriction and decreased secretions from the nasal mucosa
- Can also be used IV (emergently) to increase __ __
- alpha-1
- decongestant
- blood pressure
91
Clonidine
- Selective __ agonist - Acts on presynaptic terminals to reduce __ transmission in the central nervous system
- Main indication is as an __ – reduction of sympathetic nervous system activity
- alpha-2
- adrenergic
- antihypertensive
92
Isoproteronol – activates __ and __ receptors
Dobutamine – activates __ receptors with less __ receptor effect
Both increase cardiac output… but dobutamine will increase blood pressure the most
Why would this be?
beta-1; beta-2
beta-1; beta-2
Increase HR --> increases contractility --> increases SV
93
Albuterol, salbutamol are inhaled selective __ agonists
Activate __ receptors in the bronchioles
beta-2; beta-2
