(4) DSA: Anatomy Of Autonomics (Brauer) Flashcards
What are the first two divisions of the PNS?
Sensory (afferent)
and
Motor (efferent)
Describe the breakdown of the peripheral nervous system
The ANS is subdivided into what two categories?
Sympathetic
Parasympathetic
What is the visceral motor division of the PNS responsible for?
Regulating:
Heart rate
Blood pressure
Digestion
Urination
What is the visceral sensory division of the PNS responsible for?
Monitoring sensations within visceral organs including:
- Stretch
- Temperature
- Chemical changes
- Irritation
What is unique about pain from visceral organs?
NO PAIN RESULTS when visceral organs are cut
Pain results from chemical irritation or inflammation
Visceral pain often preceived to be of ________ origin; as ________ pain
somatic; referred
What is the function of the ANS?
Regulate involuntary body functions
Maintain internal homeostasis
Generally, the sympathetic division of the ANS is….
Catabolic
Describe
Sympathetic division of ANS
Fight or flight !!!
Responsible for vasoconstriction (*exception is coronary arteries)
Describe
Parasympathetic division of ANS
“Rest and digest”
Only found in head, neck, body cavities, genitalia
Not found in body wall or limbs
All glandular secretion is parasympathetic (*exception=sweat glands)
Match the description with the ANS division:
Catabolic, Anabolic
Parasympathetic, Sympathetic
Sympathetic = Catabolic
Parasympathetic = Anabolic
Noteworthy effects of ANS on various organs
Eyes:
What dilates/constricts pupils?
Dilate = Sympathetic
Constricts = Parasympathetic
Noteworthy effects of ANS on various organs
Lungs:
Sympathetic/Parasympathetic?
Sympathetic: Bronchodilation
Parasympathetic: Constricts Bronchi
Noteworthy effects of ANS on various organs
Genital system:
Sympathetic/Parasympathetic
Sympathetic: Ejaculation
Parasympathetic: Produces erection
What is the length of postsynaptic (postganglionic) fibers of the sympathetic division?
LONG postsynaptic fibers
What is the length of postsynaptic (postganglionic) fibers of the parasympathetic division?
SHORT postsynaptic fibers
Describe the branching of:
Sympathetic fibers
Highly branched
Influence MANY organs at once
Describe the branching of:
Parasympathetic fibers
Few Branches
Localized effect
What is the neurotransmitter released by the postsynaptic axons of the:
Sympathetic division
Norepinephrine (adrenergic)
What is the neurotransmitter released by the postsynaptic axons of the:
Parasympathetic division?
Acetylcholine (cholinergic)
Where are the presynaptic (preganglionic) neurons of the sympathetic division found?
Intermediolateral (lateral) gray horn of the spinal cord
Where do presynaptic fibers of the sypathetic division exit from?
Spinal nerves
T1 –> L2/3
Sympathetic trunk ganglia
aka?
Paravertebral
or
Chain Ganglia
What is this column of neurons referred as?
Where is it found?
Intermediolateral (or lateral) column
B/w spinal cord levels T1-L2/3
How do sympathetic axons leave the spinal cord?
Via the VENTRAL ROOTS
Label the:
Sympathetic Trunk Ganglion
Sympathetic Trunk
Label the:
- Sympathetic trunk ganglion
- Sympathetic trunk
- Gray ramus communicans
- White ramus communicans
Describe how sympathetic neurons send their signals:
Sympathetic presynaptic neurons in spinal cord (intermediolateral horn) send myelinated axons through the ventral root into the spinal nerve.
White rami communicans carry these axons from the spinal nerve to the associated sympathetic trunk ganglia where they synapse.
Gray rami communicans carry postsynaptic sympathetic fibers back to spinal nerve to travel to peripheral structures
SUMMARIZE how sympathetic neurons transmit their signals:
Sympathetic presynaptic neurons in lateral horn –> White rami –> Gray rami –> Peripheral structures
Describe what is occuring in this image
Sometimes, (especially in cervial and sacral levels)…
Axons carried by white rami travel up or down the chain before synapsing with postsynaptic neurons at other levels
Axons pass through the sympathetic trunk and exit on _______________
Thoracic splanchnic nerves
Where are thoracic splanchnic nerves found?
ONLY in abdomen and pelvis
What is the function of sympathetic innervation on the thoracic splanchnic nerves?
Inhibit activity of muscles and glands in visceral organs
What is the role of the adrenal medulla in the sympathetic division?
- MAJOR ORGAN IN SYMPATHETIC NERVOUS SYSTEM
- Chromaffin cells release lots of norepinephrine and epinephrine into blood when stimulated
What forms the pelvic splanchnic nerves?
Parasympathetic division
What are the two major outflows of the parasympathetic division?
Cranial Outflow
Sacral Outflow
Where does cranial outflow of parasympathetic divison occur?
Cranial nerves
Where does sacral outflow of the parasympathetic division occur?
Via PELVIC SPLANCHNIC NERVES
What does the enteric nervous system consist of?
Neurons in the wall of the GI tract from the esophagus to the anus
What is the enteric nervous system capable of?
Autonomous functions such as:
Coordination of GI reflexes
Enteric neurons include postsynaptic neurons of cranial nerve…
TEN
*also pelvic splanchnic nerves
