3 - Autonomic Nervous System Flashcards
1
Q
The sympathetic and parasympathetic nervous system affect cardiac pump function in 3 ways.
A
- Changing chronotropism (HR)
- Changing inotropism (strength)
- Changing blood flow
2
Q
Are far the most important regulators of the peripheral circulation.
A
SNS nerves
3
Q
ANS can be subdivided by neurotransmitter secreted at the effector cell (3)
A
- Acetylcholine (SNS)
2. Epinephrine & NE (PNS)
4
Q
Is a substance that interacts with a receptor to evoke a biologic response.
A
Agonist
5
Q
Is a substance that interferes with the triggering of the response at a receptor site by an agonist.
A
Antagonist
6
Q
The ANS reflex comprises the (4)
A
- Sensors
- Afferent pathways
- CNS integration
- Efferent pathways
7
Q
Includes the part of the central and peripheral NS concerned with involuntary regulation of cardiac muscle, smooth muscle and glandular and visceral functions.
A
ANS
8
Q
These structures are the first link in the reflex arcs of the ANS, and may relay visceral pain or changes in vessel stretch.
A
Afferent fibers
9
Q
Is the highest level of ANS integration.
A
Cerebral cortex
10
Q
What is the principal site of ANS organizaton?
A
Hypothalamus
11
Q
SNS functions are controlled by nuclei in which part of the hypothalamus?
A
Posterolateral
12
Q
PNS functions are governed by nuclei in which part of the hypothalamus?
A
Midline and anterior
13
Q
Which part of the hypothalamus is in charge of regulation of temperature?
A
Anterior
14
Q
Is the part which regulate water metabolism and are anatomically and functionally and associated with the posterior lobe of the pituitary.
A
Supraoptic hypothalamic nuclei
15
Q
Together with the hypothalamus, these two structures integrate momentary hemodynamic adjustments and and maintain the sequence and automaticity of ventilation.
A
- Medulla
2. Pons
16
Q
This area that is located within the medulla oblongata, is the primary area for relay of afferent chemoreceptor and baroreceptor information from the glossopharyngeal and vagus nerves.
A
Nucleus tractus solitarius (NTS)
Nerves related:
N = NINE (glossopharyngeal)
T = TEN (vagus)
S = SEVEN (less facial)
17
Q
These 2 tissues are only innervated by the SNS fibers (2)
A
- Sweat glands
2. Spleen
18
Q
EFFERENT SOMATIC MOTOR SYSTEM
A
Is composed of a cell body in the ventral gray matter of the spinal cord (unipolar) with its cell body in the ventral gray matter. Its myelinated axons extends directly to the voluntary striated muscle unit.
19
Q
ANS efferent motor system
A
Is a two unit (bipolar) chain from the CNS to the effector organ. The first neuron of both the SNS and PNS originates within the CNS but does not make direct contact with the effector organ. Instead, it relays the impulse to a second station, known as the ANS ganglion, which contains the second ANS (postganglionic) neuron. Its axons contact the effector organ.
20
Q
PREGANGLIONIC FIBERS both subdivisions are myelinated and are conducted at a speed of?
A
3 to 5 m/s
21
Q
POSTGANGLIONIC FIBERS are unmyelinated and conduct impulses at a slower speed of?
A
2 m/s
22
Q
3 classifications of nerve fibers
A
- Myelinated somatic
- Myelinated visceral (preganglionic autonomic)
- Unmyelinated
23
Q
3 GROUPS of nerve fibers
A
- A
- B
- C
24
Q
5 types of A nerve fibers
A
- Alpha
- Beta
- Gamma
- Delta
- Epsilon
25
Conduction velocity of A (alpha and beta) nerve fibers
120 m/s
26
Conduction velocity of A (gamma and delta) nerve fibers?
5-40 m/s (pain fibers)
27
Conduction velocity of A epsilon nerve fibers?
5 m/s
28
Conduction velocity of B nerve fibers?
3 - 15 m/s
29
Conduction velocity of C nerve fibers?
0.5 - 0.2 m/s (pain fibers)
30
The efferent SNS referred to as _____ located in what level of the vertebrae?
Thoracolumbar nervous
| T1-T12 and L1-L3
31
Upon entering the paravertebral ganglia of the lateral sympathetic chain, the preganglionic fiber may follow one of three courses. (3)
1. Synapse with postganglionic fibers in ganglia at level of exit
2. Course upward or downward in the trunk of the SNS chain to synapse in ganglia at other levels
3. Track for variable distances through the sympathetic chain and exit without synapsing to terminate in an outlying, unpaired, SNS collateral ganglion.
32
Preganglionic fibers pass directly thru what structure without synapsing in a ganglion.
Adrenal medulla
33
Collateral ganglia of these 2 ganglia are formed by the convergence of preganglionic fibers with MANY POSTGANGLIONIC neuronal bodies.
Celiac
| Inferior mesenteric ganglia
34
SNS ganglia are almost ALWAYS closer to?
The spinal cord than the organs
35
Many of the postganglionic fibers pass from the lateral SNS chain back to the spinal nerves forming what structure?
They are distributed distally to these structures (3)
These nerves are called?
Gray communicating rami
1. Sweat glands
2. Pilomotor muscle
3. Blood vessels (skin and muscle)
Unmyelinated C type fibers
36
The first 4 or 5 thoracic spinal segments generate preganglionic fibers that hat ascend in the neck to form three paired ganglia. (3)
1. Superior cervical
2. Middle cervical
3. Cervicothoracic
37
Cervicothoracic ganglion is also called?
This is formed by the fusion of what 2 ganglia?
Stellate ganglion
1. Inferior cervical
2. 1st thoracic
38
Postganglionic neurons outnumber the preganglionic neurons in an average ratio of?
20:1 to 30:1
39
The preganglionic cell bodies of the parasympathetic NS ORIGINATE in 2 areas.
1. Brainstem
| 2. Sacral segments
40
Parasympathetic preganglionic are found in what cranial nerves (4)
```
(1973)
9
10
7
3
```
41
This cranial nerve has the most extensive distribution of all the PNS.
Vagus nerve
42
The sacral fibers form the pelvic visceral nerves. These nerves supply the remainder of the viscera that are not innervated by the vagus. They are called as?
Nervi erigentes
43
The ratio of preganglionic to postganglionic nuerons in PNS is?
1:1 to 3:1
44
The right stellate ganglion distributes primarily to two areas (2)
1. Anterior epicardial surface
| 2. Interventricular septum
45
The left stellate ganglion supplies which part of the heart (2)?
1. Posterior
| 2. Lateral surface of both ventricles
46
Vagal stimulation can reduce the contractile force by as much as how many %? (Range)
10 - 20%
47
PNS innervation of the lungs is via what nerve?
SNS stimulation produces broncho dilation or constriction?
Vagus nerve
Bronchodilation
48
The terminals of the PNS postganglionic fibers release what neurotrasmitter?
Acetylcholine
49
The terminals of the SNS postganglionic fibers release what neurotransmitter?
Except for what structure?
Norepinephrine
Sweat glands
50
The PREGANGLIONIC neurons of both system secrete what neurotransmitter?
Acetylcholine
51
The terminations of both ANS are called?
Terminal effector plexus or reticulae
52
Is any compound with a catechol nucleus (a benzene ring with two adjacent hydroxyl groups) and an amine-containing side chain.
Catecholamine
53
What are the 3 endogenous catecholamines in the body?
1. Epi
2. NE
3. Dopamine
54
Stored epinephrine is chiefly located in the?
Chromaffin cells of the adrenal medulla
55
Drugs that produce sympathetic-like effect but lack a catecholamine structure are defined as?
Sympathomimetics
56
Catalyzes the conversion of tyrosine to dihydroxyphenylalanine. This is the rate-limiting step at which NE synthesis is controlled through feedback mechanism.
Tyrosine hydroxylase
57
Where does dopamine synthesis occur?
Cytoplasm of the neuron
58
This enzyme converts dopamine to NE.
Dopamine hydroxylase
59
This enzyme converts epinephrine to NE
Phenylenthanolamine N-methyltransferase
60
Release of NE is dependent in to 2 factors
This release is inhibited by 2 drugs
1. Depolarization of the nerve
2. Calcium ion permeability
1. Colchicine
2. Prostaglandin E2
61
Catecholamines are removed by three mechanisms
1. Reuptake
2. Extraneuronal uptake
3. Diffusion
62
The NE that is taken up by the extraneuronal tissue is metabolized by? (2)
To form?
MAO (monoamine oxidase)
Catechol-O-methyltransferase
Vanillylmandelic acid
63
What are the major agonists of the ANS? (5)
1. Ach
2. Epi
3. NE
4. Dopamine
5. ATP
64
Cholinergic receptors are divided in to 2?
1. Muscarinic (activates cholinergic receptors at the postganglionic PNS junction)
2. Nicotinic (are located at the synaptic junction of both SNS & PNS)
65
Low doses of nicotine produce stimulation of ANS ganglia while high doses produce blockade. This term is referred to as?
Nicotinic effect
66
The alpha adrenergic receptors are divided based on their response to alpha antagonists. This drug is a more potent antagonist of a1.
This drug is a more potent antagonist of a2.
Prazosin
Yohimbine
67
The larger epicardial coronary arteries possess what type of receptors?
a1
Epicardial vessels only contribute only 5% of the total coronary resistance. Therefore, a1 agonist have little influence on the coronary circulation.
68
Which a receptors being greater on the venous side?
a2
69
The greatest density of a receptors in the kidney is found in the? (With the a2 receptor dominating)
Thick ascending loop of henle followed by DCT then the proximal tubule
The a1 is predominant in the renal vasculature
70
The effect of NE on inotropism in the normal heart is mediated entirely through the?
Postsynaptic b1 receptor (while b1 and b2 for inotropism)
71
Presynaptic or postsynaptic?
1. Dopamine 1 receptors
2. Dopamine 2 receptors
1. Presynaptic
| 2. Postsynaptic
72
The greatest numbers of dopamine1-postsynaptic receptors are found where?
Vascular sm of the kidney and mesentery
73
DA receptors have been identified in the hypothalamus where they are involved with what function?
Prolactin release
74
A dopamine ANTAGONIST by promoting gastric emptying
Metoclopramide
75
Noted that the pulse rate is inversely proportional to the blood pressure.
What law is it called?
Etienne Marey
Marey law
76
Impulses from the carotid sinus reach the medullary sinus by?
Glossopharyngeal nerve
77
Impulses from the aortic arch reach the medullary sinus by?
Vagus nerve
78
The primary defect in the development of hypotension in spinal anesthesia is?
Decrease in venous return
79
Vagal inhibition of left ventricular contractility is accentuated as the level of SNS activity is raised. The interaction is termed?
Accentuated antagonism
80
The ANS is integrally to several endocrine systems such as (3)?
1. RAAS
2. Glucocorticoids
3. Insulin
81
What adrenergic receptor
1. Increases insulin release
2. Decreases insulin release
1. B stimulation
| 2. A stimulation
82
How does glucocorticoid increase epinephrine release?
Glucocorticoid modulates phenylenthanolamine-N-methyltransferase formation and thus synthesis of epinephrine.
83
Drugs that act on prejunctional membranes may therefore interfere with the transmitter? (6)
1. Interfere with transmitter synthesis (methylparatyrosine)
2. Interfere with transmitter storage (reserpine)
3. Stimulate transmitter release (ephedrine)
4. Interfere with reuptake of transmitter (cocaine)
5. Modify metabolism of neurotransmitter in the synaptic cleft (acetylcholinesterase)
6. Interfere with transmitter release (clonidine)
7. Stimulate postjunctional receptor
8. Interfere with transmitter agonist
84
The ultimate response of an effector organ agonist or antagonist depends on? (7)
1. Drug
2. Plasma concentration
3. Number of receptors
4. Binding by the receptor
5. Concurrent activities of other drugs and hormones
6. Cellular metabolic status
7. Reflex adjustments by the organism
85
What is both the prototypical ganglionic agonist and antagonist (high doses) agent?
Nicotine
86
This drug produces a competitive nondepolarizing block of both motor end plates and ANS ganglia.
D-tubocurare
87
This drug produces blockade by competition with Ach for receptors, thus stabilizing the postsynaptic membrane. The patient’s pupils become fixed and dilated during administration, which obscures eye signs, making it inferior to nitroprusside.
Trimethaphan
88
Cholinomimetic muscarinic drugs (3 groups)
1. Choline esters (ach, methacholine, carbamylcholine, bethanecol)
2. Alkaloids (pilocarpine, muscarine, arecoline)
3. Anticholinesterase (neostigmine, physostigmine, pyridostigmine, edrophonium, echothiophate)
89
The degree of muscarinic activity if what stucture is replaced?
Acetyl group
90
This muscarinic agonist is resistant to hydrolysis but possess mainly muscarinic activity.
Bethanecol
91
B-methyl substitution produces what muscarinic agonist?
Methacholine
92
Muscarinic agonist overdose is treated with what drug?
Atropine
93
Accumulation of Ach by anticholinesterases potentially can produce:
1. Stimulation of muscarinic receptors
2. Stimulation followed by depression of the ANS ganglia and skeletal muscle (nicotinic)
3. Stimulation with later depression of cholinergic receptor sites in the CNS
94
Anticholinesterase drugs may be divided in to two types
1. Reversible
| 2. Non reversible
95
Drugs that inhibit the anionic site are called?
Give 1 drug example of this type
Competitive inhibitors
Edrophonium
96
Drugs that inhibit the esteratic site are called?
3 drug examples of this type.
Acid-transferring inhibitors
1. Neostigmine
2. Pyridostigmine
3. Physostigmine
97
Is a tertiary amine anticholinesterase inhibitor that readily passes into the CNS
Physostigmine
98
The only therapeutic drug for irreversible cholinesterase inhibitors is?
Ecothiophate
99
This drug has been reported to reactivate cholinesterase activity by hydrolysis of the phosphate enzyme complex. It is particularly effective with parathion poisoning and is the only cholinesterase reactivator avaiable in the US.
Pralidoxime
100
This drug reduces the opening pressure of the lower esphageal sphincter, which theoretically increases the risk of passive regurgitation.
Atropine
101
Also known as oculosympathetic paresis.
Give the 3 manifestations
Horner syndrome
1. Miosis
2. Ptosis
3. Anhydrosis
102
Best known affliction associated with ANS dysfunction.
Diabetic neuropathy
103
Current recommendations for patients taking MAOIs is discontinuation for how long before a procedure.
2 weeks
104
The rate of paco2 rise in awake, preoxygenated adults with normal lungs who hold their breath without hyperventilation is?
1. In the 1st 10 seconds
2. In the next 10 seconds
3. Thereafter
7 mmHg
2 mmHg
6 mmHg
