Bowman ANS Flashcards
(127 cards)
1
Q
What composes peripheral nervous system (PNS)
A
Somatic nervous system
Autonomic nervous system
2
Q
What is the somatic nervous system?
A
Motor and sensory pathways regulating voluntary motor control of skeletal muscle
3
Q
What is the autonomic nervous system?
A
Motor and sensory pathways regulating body’s internal environment through involuntary control of organ systems (smooth muscle, cardiac muscle, and glands)
4
Q
What makes up autonomic nervous system?
A
- Sympathetic & parasympathetic nervous system<— not always physiologic antagonists
- Enteric system
5
Q
Where is autonomic nervous system located?
A
Both in CNS and PNS Coordinates and maintains steady state among the visceral (internal) orgnas
6
Q
What are preganglionic neurons?
A
Cell body is located in CNS (myelinated B fibers)
7
Q
What are postganglionic neurons?
A
Cell body in autonomic ganglia (unmyelinated C fibers)
8
Q
What is an example of sympathetic and parasympathetic not being physiological antagonists?
A
Sympathetic maintains vascular tone but parasympathetic has very little roll in maintaining vascular tone
9
Q
What autonomic centers activate the ANS?
A
- Hypothalamus - thermoregulation, regulating visceral behaviors
- Brain stem
- medulla- vasomotor/vasodilator centers
- pons- mecturition (urination)
- Spinal cord
Regulate by sending out long efferent fibers
10
Q
Where is sympathetic innervation?
A
Thoracolumbar: preganglionic neurone cell bodies are located in T1-L2/3 of spinal cord
11
Q
Where are preganglionic neuron cell bodies located in spinal cord in sympathetic innervation?
A
Intermediolateral horn of grey matter
12
Q
Where are post-gaglionic neuron cell bodies located for sympathetic innervation?
A
In ganglia
- Paravertebral chains (either side of psinal column)
- prevertebral ganglia (i.e.- celiac, superior, inferior, mesenteric ganglia in abdomen)
13
Q
Relative size of preganglionic neurons to post ganglionic for SNS?
A
Short preganglionic neurons, long post ganglionic
14
Q
What is baseline function of sympathetic nervous system?
A
Mobilized energy stores in times of need; “fight or flight” response.
15
Q
Where do sympathetic nerve fibers leave the spinal cord? Where do they travel initially?
A
- Nerve fibers leave spinal cord ventrally via the white rami
- They then travel to 22 paravertebral ganglia (sympathetic chain ganglia)
16
Q
Where can sympathetic nerves travel after the sympathetic chain ganglia?
A
- Synpase with post-ganglionic neuron at same level OR
- Move caudad or cephalad to synapse at another level
- Pass through ganglia withouth synpasing to collateral ganglia surrounding the abdominal aorta (celiac, superior mesenteric, inferior mesenteric)
- Some ganglia have inhibitory interneurons as well.
17
Q
Do preganglionic sympathetic neurons in SNS need to synapse with post ganglionic at same level?
A
No, can move up and down sympathetic chain, so it can go a lot of different places outside of spinal cord
18
Q
Of the preganglionic nerves that synapse inside sympathetic chain ganglia (aka paravertebral chain), where do the post-ganglionic fibers go? What do they affect?
A
- Return to spinal nerves via gray ramus (like a highway interchange)
- These postganglionic nerves go on to affect blood vessels, piloerector muscle and sweat glands.
19
Q
Where do the pre-ganglionic nerves that do not synapse in the sympathetic chain ganglia go?
A
They go to a peripheral chain ganglion and synapse there with the post-ganglionic fiber.
- The post-ganglionic fiber then exits to travel to various peripheral organs
20
Q
What is T1 SNS fibers travel to?
A
Ascend into paravertebral sympathetic chain to head
21
Q
Where do T2 fibers travel to?
A
Neck
22
Q
Where do T3-T6 fibers travel to?
A
Chest
23
Q
Where do T7-T11 fibers travel to?
A
Abdomen
24
Q
Where do T12-L2 fibers travel to?
A
Legs
25
What is distribution of SNS fibers based on?
Embryonic development and NOT spinal segments
26
What is another name for parasympathetic innervation?
Craniosacral
27
Where does parasympathetic innervation arise from?
* Cranial (medullary CN 3,7, 9, 10)
* Sacral (spinal cord S2-S4 region)
28
Where are post-ganglionic neuron cell bodies in PSNS located?
* Target organs
* Discrete ganglia in head and neck (i.e. ciliary ganglia)
29
What are relative sizes of pre and post ganglion in PSNS
* Long preganglionic neurons
* Short post-ganglionic
30
What is the parasympathetic function?
Conserve and restore energy
"rest or repose response"
anabolic
31
Where are most of the PSNS fibers located?
75% of PSNS fibers are in vagus (X) nerve, passing to abdominal and thoracic areas
32
Where does Vagus nerve innervate in PSNS?
* Heart
* Lungs
* Esophagus
* Stomach
* Small intestine
* liver
* gallbladder
* pancreas
* upper uterus
33
Where does cranial nerve III innervate for PSNS?
* Edinger westphal nucleus: ciliary muscles of eye
34
Where does cranial nerve V innervate?
* Submandibular gland
35
Where does cranial nerve VII innervate for PSNS?
* Superior salivatory nucleus: lacrimal, nasal and submaxillary glands
36
Where does cranial nerve IX innervate PSNS?
Inferior salivatory nucleus: parotid gland
37
Where does S2-S3 innervate?
Distal colon, rectum, bladder, lower uterus, external genitalia
38
What is the ciliary ganglion?
Where preganglionic inpus from Edinger-Westphal nucleus synapse
39
What is pterygopalatine and submandibular ganglia?
Receive preganglionic input from superior salivatory nucleus
40
What is otic ganglion
Receive preganglionic input from inferior salivatory nucleus
41
PSNS is rest for organism but ______ for visceral functions such as digestion
excitatory
42
What is most important function of SNS?
Vasomotor tone (small degree happening at all times, not just in fight/flight mode)
43
Sympathetic is amplification response with ____ innervation
Diffuse
44
Sympathetic controls response to...
* Postural changes
* Exercise
* Emergency massive response (fight or flight)
45
Parasympathetic Nervous system does ____ and ____ \_\_\_\_ resposnes
Discrete; narrowly targeted
46
Both parasympathetic and sympathetic nervous system exhibit baseline tone? T/F
True. HR- predominantly vagal predominance
Blood vessels- SNS tone
47
What receptor types and neurotransmitter in somatic efferent system?
Acetylcholine at nicotinic receptors
48
What is pre/post neurotransmitter and receptor for blood vessels?
Preganglionic neuron- Ach and nicotinic receptor
Postganglionic- Norepinephrine at andrenergic receptors
49
What are pre/post ganglionic neurotransmitters and receptor types at sympathetic system for sweat glands?
* Preganglionic- ACh (nicotinic)
* Postganglionic- ACh (muscarinic receptor)
50
What is neurotransmitter/receptor at adrenal medulla?
* Preganglionic nerve synapses at adrenal medulla with ACh at a nicotinic receptor
* Adrenal medulla produces 80% epinephrine, 20% norepinephrine released by adrenal gland
51
What is pre/post ganglionic fibers neurotransmitter at receptor for parasympathetic system?
* Preganglionic ACh (Cholinergic- nicotinic receptor)
* Post ganglionic ACh (Cholinergic- muscarinic receptor)
Always secretes Acetylcholine
52
Sympathetic preganglionic fibers in general secrete what and act on what?
Neurotransmitter= Secrete ACh
Receptor= Cholinergic (nicotinic ntype)
53
What are sympathetic postganglionic fibers neurotransmitter and receptor?
Neurotransmitter= Secrete Norepinephrine (EXCEPTION IS SWEAT GLANDS: *they excrete ACh at muscarinic ( adrenal as well?))*
Receptor: adrenergic
54
What are the 3 majors anomalies to sympathetic innervation "rule"
* Adrenal medulla (acts like a ganglia but it releases NE and EPI as HORMONES)
* Norepi 20%
* Epi 80%
* Sweat glands
* innervated anatomically by SNS
* Post ganglionic nerve releases Ach onto muscarinic Ach
* Thus "sympathetic cholingergic fibers"
* Blood vessels smooth muscle
* Have no direct innervation by PSNS (still has RECEPTORS for PSNS substances)
* muscarinic Ach receptors present on blood vessels (activate NO with eventual vasodilation with circulating Ach)
55
What are types of cholinergic receptors?
* Nicotinic ACh receptors
* Nm and Nn (nicotinic autonomic ganglia)
* Muscarinic Ach
* M1-5 (G-protein coupled)
56
What are the adrenergic receptors?
* Sympathetic side
* Alpha 1,2
* Beta (1, 2, 3)
57
What is process of activation of G-protein coupled receptors? Which receptors do this?
* Dopa, Beta, Alpha
* NT binds to receptor and activates the G-protein
* G-protein will activate or inhibit an intracellular enzyme (adenylate cyclae--\> cAMP, phospholipase C) or will open or closee an ion channel
* Uusally g-protein "cascade" will have eventual positive or negative ffect on amount of intracellular Ca= physiological effect
58
What does specific effect of neurotransmitter depend on?
* Type of receptor stimulated
* Receptor density in given tissue
* What the second messengers activate at a molecular level in the cell
59
What will receptors do in response to plasma concentrations of neurotransmitters?
Up or down regulate
60
What does Adenylate Cyclase do?
* Activated cAMP= smooth muscle dilation
* increase cAMP= vasodilation (also increased strength of cardiac contraction, increased HR)
* Decreased cAMP= vasoconstriction
61
What does PLC (phospholipase C) do?
* Activates IP3 (inositol triphosphate) and DAG (diacylglycerol)
* Results in increased PKC (Protein Kinase C) and increased free Ca
* VASOCONSTRICTIon from Ca
62
Gαq receptors IN GENERAL do what?
1. PLC (phospholipase C) activated
2. Increase IP3 (Inositol trisphosphate) and DAG
3. PKC (protein kinase C) and increased free Ca stores
In general, causes more contraction and is EXCITATORY
63
Gαi in general does what?
**Inhibitory**!
* Inhibit adenylate cyclase
* Decrease cAMP
* **Increase K conductance--\> hyperpolarize cell**
64
What is general activity of Gαs receptors?
* Activate adenylate cyclase
* Increase cAMP
65
What effect do M1 receptors have?
* NT= ACh
* G protein- Gαq
* Signal- excitatory CNS. Modulatory at ganglia
* 2nd messenger- PLC activated--\> IP3 &DAG--\> PKC and increased free Ca with decreased K conductance
* Physiologic response (depends on tissue)- Increased CNS activity, modulation at ganglia
66
What do M2 receptor types do?
* Ach neurotransmitter
* G-protein: **Gαi**
* Signal: **inhibitory** cardiac
* 2nd messenger: **Inhibit** adenylate cycale--\> **decrease** cAMP--\> **Increase** K conductance
* Physiologic response (depends on tissue): **Decreased** cAMP **slows** HR and **decreases** contractility
67
What do M3 receptors do?
* AcH neurotransmitter
* G protein- **Gαq**
* Signal- **excitatory** smooth muscle and glands
* 2nd messengers: PLC activated--\> IP3 & DAG--\> PKC and **increased** free Ca2+
* Physiologic response: Smooth muscle **contraction**
68
What do Nn receptors do? (nicotinic n type)
* AcH neurotransmitter
* Ligand gated ion channel
* Signal: excitatory ganglia CNS
* 2nd messenger: Increase Na and K permeability
* Physiologic resposne: depolarization
69
What do Nm receptors do?
* Neurotransmitter- ACH
* Ligand gated ion channel
* Signal: excitatory NMJ
* 2nd messenger: Increased Na and K permeability
* Physiologic response: depolarization
70
What do α1 receptors do?
* Neurotransmitter: NE/EPI
* G-protein: Gαq
* Signal: excitatory blood vessels
* 2nd messenger: PLC activated--\> IP3 &DAG--\> PKC and increased free Ca
* Physiologic response: smooth muscle- vasoconstriction
71
What do α2 receptors do?
* Neurotransmitter: NE/EPI
* Gprotein: Gαi
* Signal: inhibitory blood vessels. Pre-synaptic CNS post-synpatic
* 2nd messenger: Inhibit adenylate cyclase--\> decrease cAMP--\> Increase K conductance
* Physiologic response:
* Decreasesd cAMP increases smoother muscle contraction.
* Increase K results in hyperpolarization
* Can happen **presynaptically** and cause **decrease** in neurotransmitter release
* **Post** **synaptically** it can **decrease** **cAMP** and cause smooth muscle **contraction**
* **Depends on where receptor is (pre/post synapse)!!!**
72
What do β1, 2, 3 do?
* Neurotransmitter: **NE**/**EPI**
* G-protein: **Gαs**
* Signal: **excitatory** or **inhibitory** depends on cAMP actions!
* 2nd messenger: Activate adenylate cyclase--\> **increase** cAMP
* Physiologic response:
* Increased cAMP **relaxes** **smoothe** muscle
* **stimulates** cardiac **contractility**
* **increases** HR
73
Whichmuscarinic receptors increase IP3?
M1, M3, M5
74
Which muscarinic receptors inhibit adenylyl cyclase and reduce cAMP?
M2, M4
75
Where are M1 receptors located?
CNS, stomach
76
Where are M2 receptors located?
Widely expressed
* **Cardiac** (**decrease** **inotropy**/**chronotropy**) modulating HR in SA node/AV node
* Ganglia **smooth** **muscle** bladder, Gi, uterus- **contract**
77
Where is M3 located?
* Smooth muscle
* Glandular tissues
* Work with M2
78
Where are M4 receptors?
CNS (ganglia)
79
Where are M5 receptors?
* Cerebral blood vessels
* pupil
* esophagus
* parotid gland
80
Where are Nm receptors?
Skeletal muscle at NMJ
81
Where are Nn receptors?
Autonomic ganglia, adrenal medulla, CNS
82
Adrenergic=
sympathetic
83
Cholinergic=
parasympathetic (however not always....just in general)
84
What is acetylcholine?
* Synthesis
* choline (active transport brings into cytoplasm)
* acetyl coenzyme A (formed by mitochondria)
* form acetylcholine under influence of enzyme choline acetyltransferase
* Storage
* stored in synaptic vesiclaes and released in response to action potential
85
What is the metabolism of acetylcholine?
* Brief effect \<1ms, RAPID hydrolysis by acetylcholinesterase to choline and acetate
* Choline transported back into nerve endings used for synthesis of new acetylcholine
86
What is norepinephrine's neurotransmitter selectivity?
α1= α2; β1\>\>\>\>\>\>\>\>\>\> β2 \<- NO CLINICAL RESPONSE FOR NE
87
What is epinephrine's receptor selectivity?
* α1=α2
* β1=β2
88
What receptor selectivity does dopamine exhibit?
* D1=D2\>\> β\>\>α \<- some activity, not all to same degree
89
Why would it make sense that B2 receptors are present in many tissues but not innervated?
NE is released by post-ganglionic nerves in SNS BUT NE does not bind to B2 receptors. So therefore we would never have any response and rely instead on epi
90
What is pathway for formation of adrenaline?
91
How is norepinephrine formed?
* In cytoplasm dopamine formed
* Dopamine enters synaptic vesicle
* in synaptic vesicle converted to norepinephrine
92
How is norepinephrine stored and release?
* Norepi stored in vesicle until action potential
* With action potential, the norepi is released from postganglionic SNS nerve endings in ECF via exocytosis
93
What is the termination of action of norepinephrine?
* **Reuptake** back into postganglionic sympathetic nerve endings
* #1- 80% released NE can be resused
* **Dilution** by diffusion from receptors
* **Metabolism** by enzymes monoamine oxidase (MAO- cytoplasm) and catechol-o-methyltransferase (COMT- liver)
94
How is epinephrine formed?
* Synthesized in medulla of adrenal gland (chromaffin cells) in same enzymatic patheway that converts the amino acid tyrosin into NE and dopamine (epi is final step)
95
How is epinephrine stored and released?
* Released after stimulation of adrenal medulla by pre-ganglionic sympathetic neurons by Ach
96
How is epinephrine's action terminated?
COMT and MAO
97
What is effect of α 2 presynaptic versus α2 postsynaptic?
* Presynaptic will cause hyperpolarization\<--- feedback mechanism for neuron
* Postsynaptic will cause decreased cAMP and vasoconstriction
98
What is venillylmandelic acid (VMA)?
Metabolite released in urine from breakdown of NE and Epi. Can diagnose pheochromocytoma
99
α1 at vascular smooth muscle (i.e. blood vessels, sphincters, bronchi) causes...
contraction
100
α1 at iris (radial muscle) causes?
Contraction (DILATES pupils= mydriasis)
101
α1 at pilomotor smooth muscle?
Erects hair
102
α1 at prostate and uterus?
Contraction
103
α1 in heart causes?
Increase force of contraction
B1 more important though
104
α1 at pancreas?
Decreased insulin secretion (oppostie B2)
105
α2 at platelets?
Aggregation
106
α2 at adrenergic and cholinergic nerve terminals \*presynpatic
Inhibits transmitter release
Decrease BP and HR
107
α2 CNS actions?
Sedation and analgesia
via decreased SNS outflow from brainstem
108
α2 at vascular smooth muscle?
* Contraction (post-synaptic)
* Dilation (presynaptic, CNS)
109
α2 at GI tract?
Relaxation (presynaptic)
110
B1 receptors at heart?
Increased force
Increased rate of contraction (SA and AV node)
111
B1 receptors at kidneys?
Stimulation of renin release, increase angiotensin II, increase aldosterone, increase BP
112
B2 receptors at respiratory, uterine, vascular, GI, detrusor of bladder (visceral smooth muscle)
Promotes smooth muscle relaxation
113
B2 receptor mast cells
Decrease histamine release
why we give epi for anaphylaxis!!
114
B2 skeletal muscle effect?
* Potassium uptake
* dilation vascular beds
* tremor
* increase speed contraction
*
115
B2 liver effect?
Glycogenolysis
Gluconeogenesis
116
B2 effect at pancreas?
Increase insulin secretion (in order to get glucose into cell)
117
B2 effect at adrenergic nerve terminals
increase release NE
118
B1/3 effect on fat cells?
Activate lipolysis; themogenesis
119
D1 effect at smooth muscle?
Post synaptic location: Dilates renal, mesenteric, coronary, cerebral blood vessels
120
D2 effect at nerve endings?
Pre-synaptic- modulates transmitter rlease; nausea, vomiting
121
Adrenal medulla is innervated by _______ fibers that bypass the paravertebral ganglia
preganglionic
122
The fibers to adrenal medulla go directly from spinal cord to adrenal medulla (T/F)
TRUE
123
The cells of the adrenal medulla are anaglogous to \_\_\_\_\_
post-ganglionic neurons
124
SNS stimulation of adrenal gland causes release of what catecholamines hormones?
Epinephrine 80%
Norepinephrine 20%
125
Process of release of epinephrine by adrenal medulla?
* Occurs after acetylcholine is released by preganglonic cholinergic fibers
* Ach increases the permeability of Ca by acting on plasma membrane receptors of adrenal medulla cells
* Calcium ions result in exocytosis of the hormones from adrenal medulla into systemic circulation
* Results= similar to direct stimulation by SNS, however prolonged response 10-30 seconds (COMT)
126
What is sympathetic activation process?
127
Continuation of sympathetic activation?
