Autonomics Flashcards
The CNS can be broken down into…
Afferent and Efferent Division
Define: Afferent Division of CNS
Brings info from internal and external environment to CNS away from PNS
The Afferent Division of the autonomic nervous system can be broken into…
Sensory Stimuli
Visceral Stimuli
Define: Peripheral Nervous System
Nerve fibers that run between PNS and CNS
Define: Efferent Division
Takes info from CNS to muscles and glands
The Efferent Division can be broken into…
Somatic Nervous System
Autonomic Nervous System
Somatic Nervous System has ___ control
voluntary
Autonomic Nervous system has ___ control
involuntary
The somatic nervous system is made up of…
Motor Neurons
The autonomic nervous sytem is made up of…
Sympathtic Nervous System
Parasympathetic Nervous System
Which system effects skeletal muscle?
Somatic Nervous System
Which system effects smooth muscle, cardiac muscle, glands?
Autonomic Nervous System
Which system is “Fight or Flight”?
Sympathetic Nervous System
Which system is “Rest and Digest”
Parasympathetic Nervous System
Define: Mechanoreceptors
stretch, sound waves
Define: Osmoreceptors
Solute concentration
Define: Chemoreceptors
Specific chemicals (smell, taste, O2, CO2, glc, aa, fats)
How does the CNS control mucles and glands?
Efferent Division
How many different neurotransmitters are released from efferent nerves to influence all neurally controlled effector responses?
2
ACh, NE
Control: Somatic Nervous System
Voluntary from cerebral cortex
Control: Autonomic Nervous System
Involuntary from hypothalamus
Motor Neuron Pathway: Somatic Nervous System
1-neuron
CNS to Effector
Motor Neuron Pathway: Autonomic Nervous System
Usually 2-neurons
pre: CNS to ganglion
post: ganglion to effector
Neurotransmitter: Somatic Nervous System
ACh
Neurotransmitter: Autonomic Nervous System
All pre: ACh
Parasympathetic post: ACh
Most sympathetic post: NE
Chromaffin (adrenal medulla): NE & EPI
Target: Somatic Nervous System
Skeletal Muscle
Target: Autonomic Nervous System
Smooth/Cardiac muscle
glands
Response: Somatic Nervous System
Contraction
Response: Autonomic Nervous System
Contract/relax smooth muscle
Inc/Dec rate and force of contraction of cardiac muscle
Inc/Dec secretion of glands
Somatic Nervous System
Spinal cord -> Somatic Motor Neuron (Myelinated) -> ACh, Effector: Skeletal Muscle
Autonomic Nervous System: Sympathetic preganglionic neuron (myelinated)
Spinal cord -> sympathetic preganglionic neuron -> ACh, autonomic ganglion -> Sympathetic postganglionic neuron (unmyelinated) -> NE, Effectors: glands, cardiac muscle, smooth muscle
Autonomic Nervous System: Parasympathetic
Spinal cord -> parasympathetic preganglionic neuron -> ACh, autonomic ganglion -> parasympathetic postganglionic neuron -> ACh, Effectors: glands, cardiac muscle, smooth muscle
Autonomic Nervous System: Adrenal Medulla
Spinal cord -> sympathetic preganglionic neuron -> ACh, adrenal medulla -> releases neurotransmitters: Epinephrine, NE
What is the structure of the Sympathetic Nervous System?
Shorter preganglionic nerurons
Long postganglionic neurons extend across body
What is the structure of the shorter preganglionic neurons in the Sympathetic nervous system?
Originate from thoracolumbar region of SC T1 - L2
Travel to a ganglion
synaose with a postganglionic neuron
Sympathetic Nervous System: Preganglionic Fiber neurotransmitters
ACh
Sympathetic Nervous System: Postganglionic Fiber neurotransmitters
NE
Sympathetic Nervous System: Adrenal Medulla Neurotransmitter
EPI
NE
What are the effects of the sympathetic nervous system?
Fight or Flight
Sympathetic Nervous System: What does mass activation do?
Prepares for intense activity: HR increases, Bronchodilation, Blood glucose inreases
Sympathetic Nervous System: What happens to GI motility?
decreases
Sympathetic Nervous System: What happens to Sphincters?
Contract
Don’t want to lose nutrients
Sympathetic Nervous System: Relaxes…
Detrusor muscle (bladder stores urine)
Ciliary Muscle (increases focal distance)
Sympathetic Nervous System: Eye
Mydriasis
dilation of pupil
Oh My Dry Eyes
What is the structure of the Parasympathetic Nervous System?
Longer Preganglionic Neurons
Shorter Postganglionic neurons extend to effector
What is the structure of the longer preganglionic neurons in the Parasympathetic nervous system?
Originate from craniosacral region
travel to ganglion
synapse with a postganglionic neuron
Parasympathetic Nervous System: Neurotransmitters
ACh
How is the Parasympathetic Nervous System activated?
Parasymathetic. nerves are stimulated (activated) individually, not as a whole
What relaxing effects does the Parasympathetic Nervous System cause?
Decreases HR
Dilates visceral blood vessels (GI)
Increases digestive activity
What does the Parasympathetic Nervous System do to bronchi?
causes bronchoconstriction
Parasympathetic Nervous System: What happens to GI motility?
Increases
Parasympathetic Nervous System: What happens to Sphincters?
relax
Parasympathetic Nervous System: Eye
Miosis
pupil contraction
What is the major preganglonic nerve in the parasymapthetic nervous system?
Vagus Nerve (CN X)
Most visceral organs are innervated by….
Both
Sympathetic and Parasympathetic fibers
What are the effects of dual innervationsof organs?
Antagonistic
Complementary
Cooperative
Define: Antagonistic Dual Innervation
actions of the SNS and PSNS counteract each other
can work on same or different cells
What is an example of antagonistic dual innervation on the same cells?
Heart Rate
What is an example of antagonistic dual innervation on different cells?
Pupil dilation or contraction
Define: Complementary Dual Innervation
Actions produce similar effects
What is an example of completemtary dual innervation?
salivary gland secretion
Define: Cooperative Dual Innervation
actions produce different effects that work together to produce desired effect
What is an example of cooperative dual innervation?
Sexual function in males
point and shoot
What part of male sexual function does the parasympathetic nervous system control?
erection
What part of male sexual function does the sympathetic nervous system control?
ejaculation
How does dual innervation in organs work?
usually both systems are partially active, but one can dominate
How is regulaiton of dual innervation achieved?
by increasing or decreasing firing rate
What is the goal of dual innervation when the PSNS dominates?
general housekeeping
What is the goal when the SNS dominates?
increase flow of oxygenated nutrient rich blood to skeletal muscles
What happens when the PSNS and SNS are balanced?
organ is “Alert”
What is the advantage of Dual innervation?
precise control over organ’s activity
Define: Parasympathetic Tone
Parasympathetic nervous system dominates in dual innervation
Define: Sympathetic Tone
Sympathetic nervous system dominates in dual innervation
Innervated blood vessels are predominatly innervated by….
sympathetic nervous system
Define: Sympathetic Vasomotor Tone
a base firing frequency of sympathetics
Blood Vessels: Patial constriction
helps detect BP
Blood Vessels: Inreased firing of SNS
vasoconstriction
Blood Vessels: Decreases firing of SNS
Vasodilation
What are the only blood vessels that receive both sympathetic and parasympathetic fibers?
Penis
Clitoris
GI
Which system are sweat glands innervated by?
Sympathetic Nervous System
In sweat glands, postganglionic fibers release…
ACh
Which system is the Adrenal Medulla innervated by?
Sympathetic Nervous System
Where do neurons in the adrenal medulla synapse?
directly on adrenal gland
What happens after neurons synapse directly on the adrenal gland?
release ACh
activate nicotinic receptors
adrenal glands release EPI into systemic circulation
Which system innervates arrector pili muscles (muscles attached to hair follicles)?
Sympathetic Nervous System
Which autonomic NT receptor is faster?
nicotinic
Define: Muscarinic Receptor (mAChR)
Autonomic NT receptor
Binds GTP
Slower
What happens to ACh after it is released by the SNS or PSNS?
ACh binds cholinergic receptor
cholinergic receptor binds muscarinic or nicotinic receptor
Define: Metabotropic Receptors
G Protein-Coupled Receptor
slower
a lot of metabolic steps
bind GTP
muscarinic receptor
Define: Ionotropic Receptor
Ligand-gated ion channel
Faster
nicotinic
Sympathetic innervation of adrenal medulla
preganglionic neuron -> ACh (ganglionic transmitter) -> nicotinic receptor on adrenal medulla -> EPI released into blood (neuroeffector transmitter) -> adrenergic receptoron effector organs
Sympathetic Nervous System Pathway
preganglionic neuron -> ACh (ganglionic transmitter) -> ganglion -> nicotinic receptor on ganglion -> postganglionic neurons -> Norepinephrine -> Adrenergic receptor on effector organs
Parasympathetic Nervous System pathway
preganglionic neuron -> ACh (ganglionic transmitter) -> ganglion -> nicotinic receptor on ganglion -> postganglionic neurons -> ACh -> Muscainic receptor on effector organs
What are the five major cross-membrane signaling mechanisms?
- Transmembrane diffusion
- Transmembrane enzyme receptors
- Transmembrane receptors
- Transmembrane channels
- G Protein-coupled receptors
How can receptors be manipulated?
by drugs
Drugs that enhance or mimic the receptor
Agonist
Drugs that block the receptor
Antagonist
What does atropine do?
it blocks the PSNS by blocking the effects of ACh on M receptors but doesnt effect N receptors or the SNS
What is Atropine used for?
to suppress salivary and bronchial secretions before surgery