ANS Anatomy And Phys Flashcards
(166 cards)
1
Q
What 3 forms can an extracellular signal take form?
A
Chemical
Electrical
Mechanical
2
Q
What are the 3 categories of membrane bound receptors?
A
Ion channel
G-protein couple receptor (GPCR)
Enzyme linked receptor
3
Q
What are the two ways a GPCR works?
A
Opens/closes a channel
Activates/inactivates an enzyme inside the cell
4
Q
Where are intracellular receptors located?
A
In the cytoplasm or nucleoplasm
(Steroids)
5
Q
What are the 3 subunits in a g-protein receptor?
A
Alpha, beta, and gamma
6
Q
What do Gs and Gq proteins do?
A
STIMULATE (turn ON am effector)
7
Q
What do Gi proteins do?
A
INHIBIT (turn OFF an effector)
8
Q
What are the main second messengers?
A
cAMP
cGMP
IP3
DAG
Calcium
9
Q
What is the receptor, signal transduction, effector and second messenger for alpha 1?
A
Signal transduction: Gq
Effector: ^ phospholipase C
Second messenger: ^ IP3, DAG, Ca
10
Q
What is the receptor, signal transduction, effector and second messenger for alpha 2?
A
Signal transduction: Gi
Effector: decreased adenylate cyclase
Second messenger: decrease cAMp
11
Q
What is the receptor, signal transduction, effector and second messenger for Beta 1?
A
Signal transduction: Gs
Effector: ^ Adenylate Cyclase
Second messenger: ^ cAMP
12
Q
What is the receptor, signal transduction, effector and second messenger for Beta 2?
A
Signal transduction: Gs
Effector: ^ adenylate cyclase
Second messenger: cAMP
13
Q
What is the receptor, signal transduction, effector and second messenger for beta 3?
A
Signal transduction: Gs
Effector: ^ adenylate cyclase
Second messenger: ^cAMP
14
Q
What is the receptor, signal transduction, effector and second messenger for nicotinic (ANS, NMJ, CNS)?
A
Ion channels
15
Q
What is the receptor, signal transduction, effector and second messenger for M1, M3, and M5?
A
Signal transduction: Gq
Effector: ^ Phospholipase C
Second messenger: ^ IP3, DAG, Ca
16
Q
What is the receptor, signal transduction, effector and second messenger for M2 and M4?
A
Signal transduction: Gi
Effector: decreased adenylate cyclase
Second messenger: decreased cAMP
17
Q
What is the receptor, signal transduction, effector and second messenger for dopamine 1?
A
Signal transduction: Gs
Effector: ^ adenylate cyclase
Second messenger: ^ cAMP
18
Q
What is the receptor, signal transduction, effector and second messenger for dopamine 2
A
Signal transduction: Gi
Effector: decreased adenylate cyclase
Second messenger: decrease cAMP
19
Q
What is the receptor, signal transduction, effector and second messenger for vasopressin 1
A
Signal transduction: Gq
Effector: ^ phospholipase C
Second messenger: ^ IP3, DAG, Ca
20
Q
What is the receptor, signal transduction, effector and second messenger for vasopressin 2?
A
Signal transduction: Gs
Effector: ^ adenylate cyclase
Second messenger: ^ cAMP
21
Q
What is the receptor, signal transduction, effector and second messenger for histamine 1?
A
Signal transduction: Gq
Effector: ^ phospholipase C
Second messenger: ^ IP3, DAG, Ca
22
Q
What is the receptor, signal transduction, effector and second messenger for histamine 2?
A
Signal transduction: Gs
Effector: ^ adenylate cyclase
Second messenger: ^ cAMP
23
Q
What does Beta 1 affect the heart?
A
> Positive Inotrope
positive chronotropy
positive dromotropy
24
Q
What does Beta 2 do to the lungs?
A
Bronchodilation
25
What does a1 do to the GI tract?
Vasoconstriction sphincter contraction
26
What does alpha 1 do to the glands?
> Increased sweating
> decreased pancreatic activity
27
What does a1 and Beta 2 do to the urinary tract?
Bladder sphincter contraction
^ renin secretion (I’m almost positive this is actually Beta 1 stimulation)
28
What does alpha 1 do to the skin?
Vasoconstriction
29
What does beta 2 do the skeletal muscle?
Vasodilation
30
What does alpha 1 cause in the pupils?
Dilation
31
What does M2 do in the heart?
> negative inotropy
> negative chronotropy
> negative dromotropy
32
What does M3 do in the lungs?
Bronchoconstriction
Increased gland secretions
33
What does M3 do in the GI system?
> increased motility
> sphincter relaxation
> increased gland secretion
34
What does M1 and M3 do to the glands?
> ^ salivation
> ^ lacrimination
> ^ pancreatic activity
35
What does M3 do to the urinary tract?
Bladder sphincter relaxation
36
What does M3 do to the pupils?
Constriction
37
How does alpha 2 affect beta cells?
Decrease insulin release
38
How does Beta 2 affect the uterus?
Relaxes uterus
39
How does the SNS system affect the pupil?
SNS activity > alpha 1 stimulation > radial muscle contraction > MYDRIASIS (pupil dilation)
40
How does the PNS system affect the pupil?
PNS activity > muscarinic stimulation > sphincter muscle contraction > MIOSIS (pupil constriction)
41
Where is the alpha 2 receptor present?
Presynaptic in the CNS and peripheral nervous system (this is a negative feedback mechanism that reduces NE release)
Post synaptic: smooth muscle and several organs
Nonsynaptic: platelets
42
How does alpha 2 affect the nervous system?
Decreases SNS tone
Increases PNS tone
Sedation
Analgesia
Anti-shivering
43
How does alpha 2 affect the vasculature?
Vasoconstriction
44
How does alpha 2 affect the renal tubules?
Inhibits ADH (diuresis)
45
How does alpha 2 affect the pancreas?
Decreased insulin release
46
How does alpha 2 affect the platelets?
Increases platelet aggregation
47
How does alpha 2 affect the salivary glands and GI tract?
Salivary glands: dry mouth
GI tract: decreased gut motility
48
How does rapid administration of precedex cause vasoconstriction and hypertension?
Stimulates postsynaptic alpha 2 receptors in the arterial and venous circulations.
49
How many moles of ATP can be produced with 1 mole of glucose?
38!
50
What metabolizes cAMP to AMP?
Phosphodiesterase 3 (PDE 3)
51
What is one of the main PDE 3 Inhibitors?
MILRINONE!! ~ it’s an inodilator.
52
What are PDE 3 inhibitors useful in?
Beta blocker myocardial depression
Acute heart failure
Unresponsiveness to IV catecholamines
Any time a combo of increased inotropy and decreased SVR would be desirable!
53
What is the prototype nonselective phosphodiesterase inhibitor?
Theophylline
54
In vascular smooth muscle, what does cAMP inhibit?
Myosin light chain kinase
55
What is the primary neurotransmitter of the SNS?
NE
56
What are the 3 ways catecholamines are removed from the synaptic cleft?
Reuptake (main)
Diffusion
MAO and COMT
57
Which local anesthetic blocks reuptake of NE at the synapse?
Cocaine
58
What is the end-product of catacholamine metabolism?
Vanillylmandelic acid
59
What is the primary transmitter in the parasympathetic nervous system?
Ach
60
Where are Type N cholinergic receptors located?
PNS ganglia
SNS ganglia
Central nervous system
61
Where are Type M cholinergic (nicotinic) receptors located?
Neuromuscular junction
62
Where are muscarinic receptors (cholinergic) located?
Post ganglionic PNS effector organs
CNS
63
What is an antagonist of Ca at the presynaptic nerve terminal?
Magnesium!
64
What is the primary mechanism for ACh removal?
Metabolism by Acetylcholinesterase
65
What is the rate-limiting factor for ACh synthesis?
The availability of substrates, choline, and acetyl-CoA
66
What are the two locations for neurotrasmitter release in the ANS?
Ganglia and effectors (organs)
67
What are some traits about the SNS?
Origin: thoracolumbar (T1-L3)
Ganglia: near spinal cord (sympathetic chain)
Post-to-preganglionic ratio: 30:1 (postsynaptic amplification for mass effect)
Preganglionic fiber: short myelinated B fiber
Post ganglionic fiber: long unmyelinated C fiber
Neurotransmitter at the ganglia: ACh
Receptor at ganglia: Nicotinic type N
Neurotransmitter from POSTganglionic fiber: NE (ACh at the sweat glands and piloerector muscles)
Receptor at effector organ: Adrenergic (Alpha, Beta, Dopamine) and muscarinic
68
What are some traits about the PNS system?
Origin: cranial (nerves: 1973 ~ 10,9,7,2) sacral (S2-S4)
Ganglia: near in inside effector tissue/organ
Post-to-preganglionic ratio: 1:1 or 3:1
Preganglionic fiber: long myelinated B fiber
Post ganglionic fiber: short, unmyelinated C fiber
Neurotransmitter at the ganglia: ACh
Receptor at ganglia: Nicotinic (N)
Neurotransmitter from POSTganglionic fiber: ACh
Receptor at effector organ: muscarinic
69
How many paired symapathetic ganglia are there and what are they called?
22 paired called the sympathetic chain (sympathetic trunk or paravertebral ganglia)
70
What is the path for a SNS nerve? Think ganglia…
Lateral horn > ventral root > white ramus (more distal) > grey ramus
71
When would you use a celiac plexus nerve block?
Acute or chronic pancreatitis
72
When would you use a nerve block of the lower intercostal nerves?
Intraabdominal surgery
73
Where do the cell bodies is the preganglionic sympathetic fibers lie?
The interomediolateral (IML) horn of the spinal cord, also known as the lateral horn and Rexed lamina 7
74
What is often an unintended consequence of a brachial plexus block? (Not lung related)
Horner syndrome
75
What is Horner’s syndrome?
Very Homely PAM
V: vasodilation (flushing)
H: Horner’s
P: ptosis
A: anhidrosis
M: miosis
***horner’s is ALWAYs ipsilateral! Never contralateral.
76
What’s another name for the stellar ganglion block?
Cervicothoracic ganglion
77
How is the autonomic innervation of the adrenal gland unique?
It’s innervated by preganglionic sympathetic nerves (T5-T9) but there are no postganglionic nerves
78
What is pheochromocytoma?
It’s a catecholamine-secreting rumor that usually arises from the adrenal gland or extra chromaffin tissue
79
What is the classic triad of symptoms with pheochromocytoma?
Headache
Diaphoresis
Tachycardia
80
What must you block in a patient with pheochromocytoma?
Must block alpha BEFORE you block beta (A before B)
81
What are the common alpha antagonists used In pheochromocytoma?
Non-selective: phenoxybenzamine and phentolamine
Alpha 1 selective: doxazosin and prazosin
82
What happens if you block beta receptors first in pheochromocytoma?
You can cause heart failure!
Beta 1 reduces inotropy and can precipitate CHF in a patient with an increased SVR
83
What should you anticipate prior to removal of the catecholamine-secreting tumor In pheochromocytoma?
HTN, tachycardia, and hyperglycemia
***use nitro, clevidipine, nicardipine for HTN and short acting BB for tachycardia
84
What should you anticipate following the removal of a pheochromocytoma tumor removal
After removal, no catecholamines are being released.
***expect hypotension and hypoglycemia
Choose NEO, NE, vaso
85
What drugs should you avoid in pheochromocytoma?
>Histamine releasing agents: sux, Atracurium, morphine, Mivacurium
> indirect-acting sympathomimetics (ephedrine)
> SNS activators: desflurane, ketamine, pancuronium, and naloxone
86
Stimulation of which receptor results in a transcellular potassium shift?
Beta-2
87
How does SNS activation affect glucose?
Increases glucose
**stimulates hepatocytes to release glucose and potassium into the circulation.
***it also increases insulin from beta cells (to utilize glucose, you must have insulin)
88
How does the SNS system affect potassium?
Initially, the liver causes an increase in serum potassium ~ this is short lived
*** when epi binds to beta 2 receptors on skeletal muscle and erythrocytes, it activated the Na/K pump and shifts potassium into the cells
89
What are some things that push K+ into the cell?
Alkalosis
Beta-2 agonists
Theophylline
Insulin
90
What are some things that shift K+ out of the cell (increase serum K)?
Acidosis
Cell lysis
Hyperosmolarity
Succinylcholine
91
What does the efferent limb of the SNS pathway consist of?
Preganglionic ~ myelinated B fiber
POSTganglionic ~ nonmyelinated C fiber
92
What are the five components to biological feedback loops?
>Sensor (monitors the environment and informs CNS of changes)
>Afferent pathway (links the sensor to the CNS)
>Control center (CNS ~ subcortical structures: hypothalamus, brainstem, spinal cord)
>Efferent pathway (links the control center to the effector organ/tissue ~ usually a pre/post ganglionic fiber)
>Effector organ/tissue (elicits a response to restore homeostasis; smooth muscle, cardiac muscle, glands)
93
The ANS influences all tissues except what?
Skeletal tissue
94
Which component of the feedback control arc compares and multiplies signals?
Control center
95
Which control mechanism regulates short-term BP control?
Neural
**seconds to minutes
(ANS reflexes ~ mechanoreceptors respond to stretch)
96
Which control mechanism regulates longer-term BP control?
Hormonal
Minutes, hours, even days!!
(RAAS, vasopressin, natriuretic peptides)
97
What are the 6 cardiac reflexes?
“Big Booty Babes Choose Violence Only”
B: Bainbridge
B: Barorecptor
B: Bezold-Jarisch
C: Chemoreceptor
V: Vasovagal
O: Oculocardiac
98
What is the best way to think about the baroreceptor reflex?
High-pressure arterial baroreceptor reflex
^ BP ~> decreased HR, contractility, and SVR
Decreased BP ~> ^ HR, contractility, and SVR
99
How does chronic HTN affect the baroreceptor loop?
Increases the BP set point
**takes 1-3 days
100
What are the two afferent pathways in the baroreceptor reflex?
Transverse aortic arch ~ VAGUS n. 10
Carotid bifurcation ~ carotid sinus (Hering’s n.) ~ GLOSSOPHARYNGEAL n. 9
101
In the baroreceptor reflex arch, what is considered the “control center,” where sensory information is interpreted and an integrated response is formed?
Nucleus tract is solitaries (NTS) in the medulla
102
What are two surgical procedures that affect the baroreceptor reflex arch?
> Carotid endarectomy ~ manipulation of the carotid bifurcation causes bradycardia
> Mediastinoscopy ~ pressure from the scope causes bradycardia
103
What is the spinal cord region of cardioaccerator fibers.
T1-T4
104
How do volatile anesthetics affect the baroreceptor reflex?
Impair! ~ in dose-dependent fashion
**iso had mild B1 agonist properties so it impairs the reflex the LEAST
105
How do IV anesthetic agents affect the baroreceptor reflex?
Propofol: impairs ~ Bradycardia
Ketamine: activates SNS ~ ^ HR (but it does have DIRECT myocardial depressant effects)
Etomidate: usually unchanged with a small decrease in SVR
106
Which IV anesthetic preserves the baroreceptor reflex?
Thiopental
**causes a decrease in SVR with compensatory rise in HR
107
How do vasodilator affect the baroreceptor reflex?
Hydralazine ~ preserves (decreased SVR with increase HR)
Nitroglycerin ~ preserves
108
What do beta blockers affect the baroreceptor reflex?
May impair reflex! ~ may present a compensatory increase in HR in the setting of hypotension
109
How do catecholamines affect the baroreceptor reflex?
>NE: preserved
>Epi/dopamine/isuprel: NOT preserved
>NEO: preserved ~ causes a compensatory bradycardia
110
What other types of medications may impair the bark EP toe reflex arch?
CCB
Ace inhibitors
PDE inhibitors
111
Which cardiac reflex is considered a “low-pressure cardiopulmonary baroreceptor reflex?”
Bainbridge reflex
112
What does the Bainbridge reflex do?
Increases in HR caused by an increase in venous return
113
During VOLUME LOADING, which reflex dominates?
Bainbridge prevails
114
During VOLUME DEPLETION, which reflex prevails?
High-pressure Baroreceptor reflex dominates
115
Which nerve is the afferent pathway in the Bainbridge reflex?
Vagus n.
116
What is the CURRENT triad of the bezold-Jarisch reflex?
Brady cardia
Hypotension
Coronary dilation
117
Where are the receptors in the Bezold-Jarisch reflex?
Chemo and mechanoreceptors in the LV wall
118
What is the control center in the Bezold Jarish reflex?
NTS and medullary cardiovascular nuclei and centers
119
What two instances can anesthetic providers elicit/see the Bezold-Jerisch reflex?
Spinal or epidural block
Shoulder surgery with regional anesthesia in sitting position
120
The Bainbridge reflex does what?
Increases HR in the setting of venous congestion (preload is too high)
121
What Bezold-Jarisch Reflex does what?
Slows the heart rate in the setting of profound hypovolemia (preload is too low)
122
What is the strongest drive (stimulus) at the peripheral chemoreceptors is what?
Hypoxia
123
What is the ACUTE CV response to hypoxemia?
Activation of the PNS ~ decreased HR, decreased Inotropy
124
What is the CV response to persistent hypoxemia?
Sympathetic activation
Increased HR/inotropy ~ increased CO
125
How does volatile anesthetic affect the chemoreceptor reflex?
Even subanesthetic (< 0.1 MAC) blunt the reflex
**opioids and nitrous oxide also affect this receptor in a dose-dependent fashion
126
What is the vasovagal response?
Vasovagal syncope or Neurocardiogenic syncope ~ transient fall in perfusion pressure to the brain.
**basically autonomic nuclei cause massive stimulation of the parasympathetic system and abolition of SNS tone
127
What can the Vasovagal reflex be triggered by?
Psychological stress
Peritoneal stretching or dissension
128
Following a Vasovagal response, what may a person notice?
Oliguria ~ d/t the high levels of ADH
129
What is the Oculocardiac reflex?
Traction on the extraocular muscles (especially medial rectus) ~ stimulate a pathway which leads to Bradycardia
130
What is the afferent and efferent limb in the Oculocardiac reflex?
“5 and dime store”
Afferent: Trigeminal CN 5
Efferent: Vagus CN 10
131
What is some common causes of the Oculocardiac reflex?
Strabismus surgery
Pressure on the globe
Ocular trauma
**retrobulbar block can cause or prevent the Oculocardiac reflex
132
What is the clinical presentation of the Oculocardiac reflex?
Bradycardia
Hypotension
Junctional rhythm
AV block
Asystole
133
What are some factors that worsen the Oculocardiac reflex?
Hypoxia
Hypercarbia
Light anesthesia
134
How do you treat the Oculocardiac reflex?
Ask surgeon to remove stimulus
Administer 100% O2
Deepen anesthetic
Administer anticholinergic
135
What happens when blood flow to the medullary vasomotor centers decreases enough to cause cerebral ischemia?
Massive SNS activation occurs
>immense vasoconstriction
>profound increase in BP, often as high as the heart can possible create
136
at what MAP does the CNS ischemic response become significant?
MAP < 50 mmHg
**it reaches its greatest degree of stimulation at a pressure of 15-20 mmHg
137
What is Cushing reflex and Cushing triad?
Cushing reflex is a specialty type of CNS ischemic response that results from increased ICP
138
What is Cushing triad?
Bradycardiac
Hypertension
Irregular resps (d/t brain stem compression)
139
What is the thermogenesis reflex?
temperature reflex to maintain a homeothermic environment
140
What area in the brian receives information regarding thermal signals?
Preoptic area (hypothalamus) ~ serves as control center
141
Is piloerection effective in humans?
No! It’s effective in animals with fur.
142
What is sweating controlled by?
Cholinergic fibers ~ these can be blocked by anticholinergics (remember the atropine acronym of being hot)
143
How do general anesthetics affect thermogenesis reflex?
All of them impair reflex!
This can lead to hypothermia!
144
What is another name for “max reflex?”
Synonymous with autonomic hyperreflexia
145
Which cranial nerves are purely sensory?
1, 2, and 8
146
Which cranial nerves are purely motor?
3, 4, 6, 11, and 12
147
What are the 4 mixed sensory and motor nerves?
5, 7, 9, and 10
148
What type of reflex is the bezold-jarisch?
Cardio-inhibitory!
**may play a cardioprotective reflex in response to noxious stimuli
149
What does Beta 3 do?
Lipolysis
150
Which receptor causes cerebral vasoconstriction?
M1
151
What are examples of adrenergic agonists?
Epi, NE, dopamine
152
what are examples synthetic catecholamines?
Isoproterenol, dobutamine
153
What are examples of synthetic noncatecholamines?
Ephedrine, phenylephrine
154
what are examples of selective beta-adrenergic agonists?
Albuterol, salmeterol
155
What are examples alpha-2 agonists?
Clonidine and dexmedetomidine.
156
What are examples of beta-1 and beta-2 antagonists?
Propranolol, esmolol
157
What are examples of mixed function alpha and beta antagonists?
Labetalol, carvedilol
158
What are examples of cholinergic agonists?
Nicotine, bethanechol, and physostigmine
159
What are examples of antimuscarinics?
Atropine, scopolamine, glycopyrrolate
160
What are examples of calcium channel blockers?
Verapamil and diltiazem
161
What are examples of phosphodiesterase inhibitors?
MILRINONE and sildenafil
162
What is an example of arginine vasopressin?
Vasopressin.
163
What are direct vasodilators/nitro dilators?
Nitro/nitroglycerin/hydralazine
164
What are examples of ace inhibitors?
Lisinopril, captopril, enalopril
165
What are examples of ARBs?
Valsartan, olmesartan, losartan
166
What are examples of anesthetic agents?
Volatile agents, propofol, and local anesthetics
