Autonomic Nervous System Flashcards
Branch of PNS that has motor and sensory pathways regulating voluntary motor control of skeletal muscle
Somatic nervous system
Branch of PNS (that is centrally located) that regulates body’s internal environment through involuntary control of organ systems, and it’s subdivisions (__ __, __ muscle, and __)
Can be controlled ___ to some extent
Autonomic nervous system
Smooth muscle, cardiac, glands. Parasympathetic and sympathetic
Voluntarily
ANS
Located in __ and __
Neurons are pre___ and post___
PNS and CNS
Ganglionic, ganglionic
Preganglionic neurons: cell body is in __ (myelinated __ fibers)
CNS, myelinated B
Postganglionic neurons: cell body is in __ __ (___ __ fibers)
Autonomic ganglia, unmyelinated C
Two divisions of autonomic subs classified __
Often but not always physiologic ___
Anatomically
Antagonists
Postganglionic fibers generally __ of CNS
Outside
ANS has a __ neuron system except for __ __, somatic system has __ neuron system
2, adrenal medulla, 1
Pre and post ganglionic are different from
Pre and post synaptic
Activation of ANS by centers in 3
Hypothalamus, brain stem, spinal cord
2 subdivisions of brain stem
Medulla and Pons
3 of medulla a jobs
Airway tone, vascular tone, and respiratory drive
ANS has partial control over 4
Systemic BP
GI motility/secretion
Urinary bladder emptying
Sweating and body temp
SNS
Innervation is located in ___ region of spinal cord, Preganglionic neuron cell bodies in __-__/__
In __ horn of __ Matter
Thoracocolumbar, T1-L2/3
Intermediolateral, grey
SNS
Post ganglionic neuron cell bodies in ___
___ chains on either side of spinal column
___ ganglia in celiac, superior, inferior mesenteric ganglia in abdomen
Ganglia
Paravertebral
Prevertebral
SNS has ___ Preganglionic neurons and __ post
Synapse ___ after leaving CNS in general
Short, long, quickly
SNS
___ energy stores
Nerve fibers leave spinal cord __ via __ rami then travel to __ __ ganglia
Mobilizes
Ventrally, white, 22 paravertebral
SNS
From paravertebral ganglia nerve fibers can synapse with postganglionic neuron at __ __ or move __ or __ to synapse at another __. Pass ganglia without synapsing to __ ganglia surrounding __ __ (__ ganglia)
Same level, caudad or cephalad
Level
Collateral, abdominal aorta, paravertebral
Prevertebral surrounding abdominal aorta are: __, __ __, and __ __
Some ganglia have __ __ as well
Celiac, superior mesenteric, inferior mesenteric
Inhibitory interneurons
Thoracocolumbar
Post ganglionic nerve cell bodies found in ganglia of __ __ exit to travel to __ __
Return to spinal nerves via __ __, travel with these nerves to __ __, __ __, and __ __
Paravertebral chains, peripheral organs
Gray rami, blood vessels, piloerector muscles, and sweat glands
Distribution of SNS fibers based on __ __ not __ __
Embryonic development, spinal segments
T1 SNS fibers go to paravertebral sympathetic chain to \_\_ T2 to \_\_ T3-6 to \_\_ T7-11 to \_\_ T12-L2 to \_\_
Head Neck Chest Abdomen Legs
What part of SNS innervates Head Neck Chest Abdomen Legs
T1 T2 T3-6 T7-11 T12-L2
Parasympathetic innervation
Preganglionic neurons arise in:
Cranial medullary CN 4
Sacral spinal cord __-__ regions
CN 3, 7, 9, 10
S2-4
PNS
Post ganglionic neuron cell bodies located in __ __ and in __ and __
__ Preganglionic neurons, ___ post
Target organs, head and neck
Long, short
PNS craniosacral division goal to:
Receives innervation from cell bodies located where. 75% where
Conserve and restore energy
Cranial nerve nuclei (3, 5, 7, 9, 10). 75% in X passing to abdominal and thoracic areas. Also sacral region of spinal cord
Preganglionic neurons of PNS travel to ganglia where
Close to organs they innervate
PNS
Vagus innervation to 9 organs
Heart, lungs, esophagus, stomach, SI, liver, gallbladder, pancreas, upper uterus
PNS
CN III where and does what
CN V where and does what
3- keeps eye focused
5- submandibular gland, secretions
CN 7 where is nucleus and which glands
CN 9 where is nucleus and which gland
7- superior salvitory nucleus, lacrimal, nasal, submaxillary glands
9- inferior Salvitory nucleus parotid gland
PNS
S2-3 (sometimes 1-4) innervates what (5)
Distal colon, rectum, bladder, lower uterus, external genitalia
Postganglionic neurons in __ ganglia including:
___ ganglion, Preganglionic input is from Edinger Westphal nucleus
Cranial
Ciliary
Postganglionic neurons
__ and __ ganglia have input from superior salivatory nucleus
__ ganglion has input from inferior salivatory nucleus
Others are located __ or __ walls of visceral organs in thoracic, abdo
Pterygopalatine, submandibular
Otic
In or near
ANS function
SNS and PNS actions often __ __ __ antagonistic
SNS: __ __, maintenance of __ __
PNS: ___, but __ __ __
But not always
Self preservation, vasomotor tone
Rest, excitatory visceral functions (digestion)
SNS effects in
Eyes
Salivary glands
Blood vessels
Dilate
Stop making saliva
Want brain flow, constricted on skin, want skeletal muscle flow, gut/kidneys don’t need flow, heart and lungs need flow
SNS effects on
Lungs
Heart
Adrenal medulla
Bronchodilation for gas exchange
Want heart to beat fast and contract strong using ATP
80% epi 20% norepi
SNS effects on
Liver
Pancreas
GI
Release glucose. Use blood from liver for other places
Release insulin to skeletal muscle, uses glucose
Want it to be relaxed, divert blood from it
SNS effects on
Bladder
Sweat glands
Relaxed, sphincter tight
Sweat, want it to cool us off
PNS effect on
Eye
Lacrimal gland
Salivary gland
Constricted
Can cry or be active
Active, digests food
PNS effect on
Heart
Lung
Upper and lower GI
Want it slow, some affect in contractility
Some constriction
Active, secretions in upper
PNS effect on
Bladder
Genitals
Contracts, sphincters able to relax
Active
SNS ___ response with ___ innervation
3 uses
Amplification, diffuse
Exercise, postural changes, emergency massive response (fight or flight)
PNS: ___ and __ targeted responses
Both systems exhibit __ __ at rest
Heart rate has __ predominance. Blood vessels has __ tone.
Discrete, narrowly
Baseline tone
Vagal. SNS.
Affect of vagus on heart rate
Why SNS tone in blood vessels important
Lowers heart rate
To get blood to brain
Somatic efferent system
How many synapses
Releases __ on a __ receptor
1
Acetylcholine on a nicotinic
Sympathetic system
Has __ synapses on blood vessel, releases __ on __ receptor
2, acetylcholine on a nicotinic receptor then norepi on a blood vessel
SNS
__ receptors release onto sweat glands. First __ on a __ receptor then __ on a __ receptor
- ACh on nicotinic, ACh on muscarinic
SNS __ receptor in adrenal medulla. __ on a __ receptor
- ACh on a nicotinic
PNS
__ receptors on salivary glands. First __ on __ receptor then __ on __ receptor
- ACh on nicotinic, ACh on muscarinic
Sympathetic Preganglionic fibers
NT- secrete what
Receptor is what
Acetylcholine, cholinergic (nicotinic n type)
Sympathetic postganglionic fibers
NT=
Receptor type=
Norepi
Adrenergic
Parasympathetic pre and post ganglionic fibers
NT= secrete what
Receptor type
Acetylcholine
Cholinergic. Nicotinic at ganglia, muscarinic at organ
3 exceptions to NT/receptor rules
Adrenal medulla (releases NE and epi as hormones) Sweat glands (sympathetic cholinergic fibers) Blood vessel- muscarinic ACh receptors but no PNS innervation
Adrenal medulla anomaly: acts as __ built releases what as what
Proportions
Only place we get what from
Ganglia, releases epi and norepi as hormones. Released systemically not just at synapse
20%norepi 80%epi
Epi
Point of having epi and norepi
Epi hits beta 1 and 2, norepi just beta 1
Sweat gland anomaly:
What it’s called and how it’s different
Innervated by SNS, post ganglionic nerve releases ACh on a muscarinic ACh receptor
Sympathetic cholinergic fiber
Blood vessel
Almost no innervation by what
But there are what receptors on them which do what
PNS
Muscarinic ACh receptors, activate NO and vasodilation if you have circulating ACh
ACh needs to be released where and why
Close to where it’s going to be used because degrading quickly, doesn’t go systemic
Cholinergic receptors PNS
Nicotinic:
Muscarinic:
NMJ and nn.
M1-5 (CNS and ganglia)
PNS adrenergic receptors: 5
Alpha 1 and 2
Beta 1, 2, 3
Mechanism of action of neurotransmitters: 1. Activation of what 2. Cascade has effect on what 3. Receptor type does what
- G protein coupled receptor
- Positive or negative effect on intracellular calcium which has a physiologic effect (inc- constriction, dec- dilation)
- Receptor type dictates activity of G protein
Different parts of body have different __ and __ of receptors
Specific effect depends on 3
Types and densities
Type of receptor stimulated, receptor density in given tissue, what the second messengers activate at a molecular level in the cell
Epi effect on vasculature and skeletal muscle
Skeletal muscle has a lot of ___. Effect of epi
Skin and GI have a lot of __. Effect of epi.
Constricts, dilates
Beta 2. Epi goes to it and dilates
Alpha 1. Vasoconstriction from epi
Receptors will do what based on plasma concentrations of catecholamines (__ or __)
Up or down regulate
Endogenous or exogenous
Adenylate cyclase activates ___= smooth muscle __
Increased=
Decreased=
CAMP, dilation
Vasodilation, increased strength of contraction/heart rate
Vasoconstriction
Camp effect on
Heart
Bronchioles
GI
Increases contractility
Dilates
Relaxes
PLC activates __ and __ resulting in increased __ and __. Leads to what
IP3 and DAG, PKC, increased calcium. Vasoconstriction
M1 ACh
G protein:
Signal:
G alpha q
Excitatory CNS modulatory at ganglia
M1 ACH
2nd messengers/output: 3
- PLC activated
- IP3 and DAG
- PKC and increased free calcium
Decreased K conductance makes cell more excitable
M2 ACh
G protein
Signal:
Gai
Inhibitory cardiac (SA node)
M2 ACH
2nd messengers: 3 steps
Physiologic response
- Inhibit Adenylate cyclase 2. Decrease cAMP 3. Increase K conductance
Slows heart rate and decrease k conductance
M3 ACH
G protein
Signal:
Gaq
Excitatory smooth muscle and glands (GI)
M3
2nd messengers: 3 steps
Physiologic response
- PLC activated 2. IP3 and DAG 3. PKC increased and free calcium
Smooth muscle contraction. Peristalsis and secretion from a gland
Nn ACH
G protein
Signal
Ligand gated ion channel
Excitatory ganglia in CNS
Nn ACh
2nd messenger output
Physiologic response
Increased Na and K perm
Depolarization
Nm AcH
G protein
Signal
Ligand gated ion channel
Excitatory NMJ
Nm ACh
Physiologic response
Depolarization
Alpha 1 epi/norepi
G protein
Signal
Gaq
Excitatory blood vessels on veins and skin
Alpha 1 epi and norepi
2nd messengers and output 3
Physiologic response
- PLC activated
- IP3 and DAG
- PKC and increased free calcium
Smooth muscle vasoconstriction
Alpha 2 epi and norepi
G protein
Signal
G alpha I
Inhibitory blood vessels pre synaptic
CNS post synaptic
Alpha 2 epi and norepi
2nd messengers 3
Physiologic response
- Inhibit Adenylate cyclase 2. Decrease cAMP 3. Increased K conductance
Decreased cAMP increased smooth muscle contraction, increased K hyper polarizes
B1,2,3 epi and norepi
G protein
Signal
G alpha s
Excitatory or inhibitory depending on cAMP actions
B 1,2,3
2nd messengers 2
Physiologic response
Activate Adenylate cyclase
Increased cAMP relaxes smooth muscle, stimulates cardiac contractility and rate
Muscarinic receptors (g protein coupled:
M1,3,5:
M2,M4:
Inositol phosphate pathway
Inhibit adenylyl cyclase reduce camp
Nicotinic receptors 2 types
Nm at NMJ in skeletal muscle
Nn autonomic ganglia in adrenal medulla, CNS
Don’t have drugs that can target which Ms specifically
Downside to this
M1,M2,M3
If you effect one, effect all of them
Acetylcholine
Synthesis:
Choline (what brings it into cytoplasm) and acetyl coA (formed from what) form acetylcholine under influence of what
Active transport
Mitochondria
Enzyme choline acetyltransferase
Acetylcholine
Storage
When released
Stored in synaptic vesicles, released in response to an action potential
Acetylcholine
Metabolism
__ effect. How broken down
Cholinergic is transported where for what
Brief. Hydrolysis by acetylcholinesterase to choline and acetate
Nerve endings for synthesis of a new acetylcholine
SNS neurotransmitter selectivity
Norepi:
A1= a2, B1. Not much B2
SNS NT selectivity
Epi
A1= a2. B1=b2.
SNS NT selectivity
Dopamine
D1=D2. B, A.
Norepinephrine
How it’s formed
Dopamine formed in cytoplasm, dopamine enters synaptic vesicle, converted to norepi in vesicle
Norepi
Storage
Release
Stored in vesicle until action potential
With action potential it’s released from postganglionic SNS nerve ending into ECF via exocytosis
Norepi Termination of action 1. \_\_\_ back into postganglionic sympathetic nerve endings (\_\_%) 2. \_\_\_ from receptors by diffusion 3. \_\_\_ by enzymes MAO and COMT
Reuptake, 80
Dilution
Metabolism
Epinephrine
Formation
Synthesized in medulla of adrenal glands by chromaffin cells, in same pathway that converts amino acid tyrosine into NE and dopamine (epi is final step)
Epi
Storage and release
Released after simulation of adrenal medulla by pre ganglionic sympathetic neurons by ACh
Epi termination of action
Look for what in urine as dx tool
COMT and MAO
VMA, in sympathetic pathway. Dx of pheochromocytoma
Alpha 1 action on
Most vascular smooth muscle
Iris
Pilomotor smooth muscle
Contraction
Contraction- dilates pupils (mydriasis)
Erects hair
Alpha 1 action on
Prostate and uterus
Heart- which is more important
Pancreas- opposite of what
Contraction
Increases force of contraction, B1
Decrease insulin secretion, b2
Alpha 2 effects on
Platelets
Adrenergic and cholinergic nerve terminals (presynaptic)
Aggregation
Inhibits transmitter release, decreases BP and HR
Alpha 2 effects on
Vascular smooth muscle
GI tract
Contraction (post synaptic) or dilation (presynaptic or CNS)
Relaxation (presynaptic)
Alpha 2 effects on
CNS
Sedation and analgesia via decreased SNS flow from brain stem
3 places alpha 2 can exist
CNS (sedation), pre synaptic terminal (hyper polarizing, decrease NT release), post synaptic (contraction and vasoconstriction)
Beta 1 effect on
Heart
Kidney
Increases force and rate of contraction through SA and AV nodes
Stimulates renin release, BP drops
Beta 2 effects on
Respiratory, uterine, vascular, GI, detrusor of bladder
Mast cells
Promotes smooth muscle relaxation
Decreases histamine release
Beta 2 effects on skeletal muscle
Potassium uptake, dilation of vascular beds, tremor, increases speed of contraction
Beta 2 effects on
Liver
Pancreas
Adrenergic nerve terminals
Glycogenolysis,
Gluconeogenesis,
Increases insulin secretion
Increases release of norepinephrine
Beta 1 and beta 3 effects on fat cells
Activates lipolysis, thermogenesis
D1 effect on smooth muscle
Post synaptic location, dilates renal, mesenteric, coronary, and cerebral blood vessels
D2 effect on nerve endings
Pre synaptic, modulates transmitter release, nausea and vomiting
