The Autonomic Nervous System Flashcards
What type of neurons does the ANS have?
motor neurons
Comment on origin of fibers, length of ganglia fibers, & location of ganglia in the parasympathetic and sympathertic system
Parasympathetic
- Brain & S2-4
- Long pre-ganglia fibres, short post-ganglia fibres
- Go to the brain, & in visceral effector organs
Sympathetic
- T1-L2
- Short pre-ganglia fibres, long post-ganglia fibres
- Close to spinal cord
What is the ganglia location of the oculo-motor and effector organ ?
Location: Ciliary ganglion
Effector organ: Eye (constrict pupils)
What is the ganglia location of the Facial CN and effector organ ?
Location:
- Pterygopalatine ganglion
- Submandibular ganglion
Effector organs:
- Nasal, palatine & lacrimal glands, snot
- Salivary glands
What is the ganglia location of the Glosso-pharyngeal and effector organ ?
Location:
Otic ganglion
Effector:
- Parotid salivary glands
What is the ganglia location of the Vagus CN and effector organ ?
Location: Intramural ganglion S2-S4
Effector organs:
- Most visceral organs (intestines, bladder, genitals
What do the sympathetic neurons produce (which horns)?
Where is it strictly located?
Produce lateral horns
Only available at T1-L2
What type of rami do preganglionic fibers in the sympathetic nervous system pass through ? where does it want to enter?
Pass through: white rami communicantes
To enter to: sympathetic trunk ganglia
Upon entering a sympathetic trunk ganglion what are 3 things that a preganglionic fibre may do?
- Synapse at the same level
- Synapse at a higher or lower level
- Synapse in a distant collateral ganglion anterior to vertebral column
Explain the steps in “synapse at the same level” in SNS
- Start at lateral horn & exit through ventral root
- Continue to ventral ramus and goes to WHITE ramus communicans
- Synapse at SAME LEVEL it ENTERS in the sympathetic trunk ganglion
- exit through GRAY ramus communicans to effector
Explain the steps in “synapse at a higher or lower level” in SNS
- Start at lateral horn & exit through ventral root
- Continue to ventral ramus and goes to WHITE ramus communicans
- Goes up the sympathetic trunk ganglion and Synapses at the SAME LEVEL IT EXITS
- exit through GRAY ramus communicans to effector
Explain the steps in “synapse in a distant collateral ganglion anterior to vertebral column” in SNS
- Start at lateral horn & exit through ventral root
- Continue to ventral ramus and goes to WHITE ramus communicans
- Continues past sympathetic trunk ganglion and synapses at a distant collateral ganglion
- exit through collateral ganglion to target organ in abdomen
Where do the SNS pathways to head synapse at? Which pathway does it follow?
What do these fibres do?
Superior cervical ganglion; synapse at higher/lower level pathway
These fibres:
- innervate skin & blood vessels of head
- Stimulate dilator muscles of iris
- Inhibit nasal & salivary glands
Where do the SNS pathways to Thorax synapse at?
What do these fibers innervate?
Cervical trunk ganglia
Innervate:
- Heart (via cardiac plexus) & lungs (via pulmonary plexus)
- Thyroid gland
- Majority of skin
Where do the SNS pathways to abdomen synapse at? Which pathway does it follow?
Which ganglia’s contribute to plexuses in this pathway?
Collateral ganglion; “Synapse in a distant collateral ganglion anterior to vertebral column” pathway
Celiac ganglion
Superior mesenteric ganglia
Inferior mesenteric ganglia
Where do the SNS pathways to pelvis synapse at? Which pathway does it follow?
Sympathetic trunk ganglia
synapse at higher/lower level pathway
Which pathway does the SNS pathway to adrenal medulla follow? What is the adaptation in this pathway?
What is its role upon stimulation?
“Synapse in a distant collateral ganglion anterior to vertebral column” pathway
- does NOT synapse (goes directly)
Secrete norepinephrine & epinephrine into blood
What are characteristics of the neurons in a somatic nervous system?
(myelinated? Releases? Type of Effect?)
- Heavy myelinated axon for fast stimulus
- releases ACh for skeletal muscle contractions
- Stimulatory effects
Contrast between the neurons in the sympathetic and parasympathetic nervous system in both pre and post ganglia axons.
myelination? release? effect of both?
What are the neurotransmitters in each axon?
Stimulatory or inhibtory in visceral organs
Sympathetic:
- pre-ganglia axon is lightly myelinated and releases ACh (cholinergic)
- post-ganglia axon is NOT myelinated and releases NE (adrenergic)
Parasympathetic?
- pre-ganglia axon is lightly myelinated and releases ACh (cholinergic)
- post-ganglia axon is NOT myelinated and releases ACh (cholinergic)
What is the exception of neurotransmitters that release in sympathetic post-ganglia axons?
They release ACh at sweat glands & some blood vessels in skeletal muscles
What are the 2 types of cholinergic receptors? What types of channels are they?
Where are they found? What is the effect of ACh release?
Ligand gates channels
- Nicotinic Receptors
Found on:
- Motor end plates of skeletal muscles
- all PRE ganglionic neurons release in SNS & PSNS
Effect: Always stimulatory - Muscarinic receptors
Found on:
- All effector cells stimulated by POSTganglionic cholinergic fibres
Effect: either be inhibitory or excitatory
What are the 2 types of adrenergic receptors? What are their effects?
Contrast their stimulation in NE & E
- Alpha: stimulatory
- Beta: inhibitory (except heart)
NE: binds more Alpha than Beta
E: Equally binds alpha and beta receptors
What is the effect of binding A1 and A2 receptor types
A1:
constricts blood vessels and visceral organ sphincters; dialtes pupils of the eyes
A2:
Inhibits NE release from adrenergic terminals
What is the effect of binding B1 B2 and B3 receptors
B1: Increases heart rate
B2: Inhibitory; relaxes lungs
B3: Stimulates lipolysis by fat cells
What type of innervation do visceral organs have?
Dual innervation
What does the parasympathetic tone do?
Slows heart
dictates normal activity levels of digestive & urinary tracts
What does the sympathetic tone do? aka?
aka vasomotor tone
Keeps blood vessels in a continual state of partial constriction
What are the localized and diffuse effects of PSNS vs. SNS:
Why is SNS effects such?
PSNS:
- short lived effect
- Highly localized control over effectors
SNS:
- Long-lasting (NE is inactivated more slowly than ACh.. remain until liver destroys it)
- Body wide effects
What are visceral reflexes similar to?
Explain pathway
Somatic reflexes.
Sensory receptor enter via dorsal root ganglia
Exits through ventral in an efferent pathway (2-neuron chain) (pre and post ganglia)
Contrast between short reflex & long reflex
Short reflex does not go to spinal cord; has only post-ganglia neuron; stay in organs
Long reflex:
- Goes to sensory pathways and then spinal cord
- has pre and post ganglia neuron
